Congenital Research Articles

Integration of long-read sequencing, DNA methylation and gene expression reveals heterogeneity in Y chromosome segment lengths in phenotypic males with 46,XX testicular disorder/difference of sex development.

46,XX testicular disorder/difference of sex development (46,XX DSD) is a rare congenital condition, characterized by a combination of the typical female sex chromosome constitution, 46,XX, and a variable male phenotype. In the majority of individuals with 46,XX DSD, a Y chromosome segment containing the sex-determining region gene (SRY) has been translocated to the paternal X chromosome. However, the precise genomic content of the translocated segment and the genome-wide effects remain elusive. We performed long-read DNA sequencing, RNA sequencing and DNA methylation analyses on blood samples from 46,XX DSD (n = 11), male controls (46,XY; variable cohort sizes) and female controls (46,XX; variable cohort sizes), in addition to RNA sequencing and DNA methylation analysis on blood samples from males with Klinefelter syndrome (47,XXY, n = 22). We also performed clinical measurements on all 46,XX DSD and a subset of 46,XY (n = 10). We identified variation in the translocated Y chromosome segments, enabling subcategorization into 46,XX DSD (1) lacking Y chromosome material (n = 1), (2) with short Yp arms (breakpoint at 2.7-2.8Mb, n = 2), (3) with medium Yp arms (breakpoint at 7.3Mb, n = 1), and (4) with long Yp arms (n = 7), including deletions of AMELY, TBLY1 and in some cases PRKY. We also identified variable expression of the X-Y homologues PRKY and PRKX. The Y-chromosomal transcriptome and methylome reflected the Y chromosome segment lengths, while changes to autosomal and X-chromosomal regions indicated global effects. Furthermore, transcriptional changes tentatively correlated with phenotypic traits of 46,XX DSD, including reduced height, lean mass and testicular size. This study refines our understanding of the genetic composition in 46,XX DSD, describing the translocated Y chromosome segment in more detail than previously and linking variability herein to genome-wide changes in the transcriptome and methylome.

What was Killing Babies in Palma, Spain? Analysing Infant Mortality Patterns Using Individual-Level Cause of Death Data, 1836–1930

This paper explores infant mortality patterns to determine the epidemiological profile of the port city of Palma, Spain between 1836 and 1930 using individual-level cause of death and testing the newly constructed ICD10h coding system. Throughout the 19th century, infant mortality was well below 150 per 1,000 live births, possibly related to the practice of extended breastfeeding and frequent vaccination campaigns. However, between 1840 and 1860, as in other Spanish and European cities, the situation deteriorated. From the 1890s to 1930, the rate was almost always below 100. Post-neonatal mortality was higher than neonatal mortality, and the two rates began to fall at different times: the former in the 1870s and the latter in the 1920s. The main causes of neonatal mortality were congenital and birth disorders, while for post-neonatal mortality they were infectious diseases, mainly airborne, followed by waterborne and foodborne diseases. The decline in these rates was influenced by several factors, including improvements to public hygiene and nutrition and the quantity and quality of water sources. With regard to sex, a more pronounced female advantage was observed in post-neonatal mortality than in neonatal mortality. The seasonality of neonatal mortality in the 19th century was characterised by two peaks in autumn and winter, possibly related to the seasonality of births. In the 20th century, a summer peak was also observed. Post-neonatal mortality showed a sharp peak in summer, which receded and gave way to a winter peak by the late 1880s.

7775 Clinical Features of NKX2-1 Gene-Related Diseases

Abstract Disclosure: S. Fukui: None. E. Tanimoto: None. N. Ujita: None. H. Miyagi: None. K. Yoshii: None. N. Yasuhiro: None. R. Horikawa: None. Background: Congenital hypothyroidism (CH) is the most common congenital endocrine disorder. The utilization of molecular genetic techniques has facilitated the detection of CH resulting from various single-gene mutations; NKX2-1 gene-related disease stands out as one etiology of symptomatic CH. We report the clinical course of three cases with CH caused by NKX2-1 pathogenic variants. Case 1: An 8-year-old boy. He was born at 40 weeks and six days of gestation, weighing 2845g, and was presented to our department by high TSH (76.1 µIU/mL) at newborn screening (NBS), and LT4 treatment was initiated. He showed motor developmental delay, and choreiform movements were exhibited at two years and 11 months without respiratory symptoms. Case 2: An 18-year-old female. She was born at 40 weeks and five days gestation, weighing 2680g, and was admitted to her previous hospital following poor weight gain at approximately six months. During hospitalization, she was initiated LT4 treatment with a TSH elevation(14.7μIU/mL). After receiving a diagnosis of idiopathic interstitial pneumonia, she was subsequently referred to our hospital. At the age of 11, an NKX2-1 mutation was identified. Case 3: An 18-year-old female. She was born at 41 weeks and three days of gestation, weighing 2364g.TSH elevation (27.9 µIU/ml) was detected at NBS, and LT4 treatment was started. Thyroid hormone levels were maintained within normal range. However, wheezing and tracheomalacia were noted around five months. Hypotonia and delayed motor development were evident, and an NKX2-1 mutation was identified at the age of 12 years. Discussion: Although NKX2-1 gene-related disorders can be readily suspected when typical symptoms of central nervous system, pulmonary, and thyroid dysfunction manifest concurrently, diagnosis is sometimes established later because of the diversity of the occurrence of these symptoms. Despite reports of choreiform movements being inevitable, they did not appear in Case 2.3 until the age of 18 years. Conversely, muscle hypotonia and delayed motor development were observed in all our cases. When atypical neurological symptoms combined with CH are observed, NKX2-1 gene-related disease should be considered since the disease is known to develop malignant tumors such as lung cancer and thyroid cancer, which can significantly affect the prognosis of patients. Conclusion: When muscle hypotonia and delayed motor development are observed in addition to hypothyroidism and respiratory symptoms, NKX2-1 gene-related disease should be suspected, and follow-up for complications, including malignancy, is essential after diagnosis. Presentation: 6/2/2024

Preoperative Evaluation, Informed Consent and Postoperative Care in Pediatric Vitreoretinal Surgery

In childhood, vitreoretinal surgery may be required due to trauma and some congenital or developmental disorders. Pediatric vitreoretinal surgery differs from that of adults in terms of etiology, anatomical and surgical characteristics, response to treatment and follow-up. This process has many challenges that require patient follow-up over many years as the child develops. Pre-operative preparation according to the age of the patient and the nature of the pathology will make it easier for the surgeon to manage all the processes. The consent of the child must be obtained in accordance with the child's cognitive abilities, in addition to the informed consent of the family. Despite surgical and technological advances in pediatric vitrectomy, anatomical and functional outcomes are worse than in adults. This article discusses pediatric vitreoretinal surgery in terms of preoperative preparation, informed consent and follow-up.

8373 High suspicion for thyroid cancer in patient with thyroid Hemiagenesis

Abstract Disclosure: L. Aoun: None. S. Almardini: None. M. Anise: None. F. Haddadin: None. F. Saliba: None. J. Zaidan: None. Background: Thyroid Hemiagenesis (THA) is a rare condition characterized by congenital absence of one lobe of the thyroid gland. Notably, THA is more prevalent in females and the left lobe is more likely to be absent with or without the isthmus. Most patients are euthyroid, and diagnosis is usually incidental, so the true prevalence of THA is uncertain as there are certainly undiagnosed cases. Studies have shown a link between THA, thyroid cancer, and hyperparathyroidism. We present a case of THA and high suspicion for thyroid cancer. Case Presentation: 54-year-old female with history of Rheumatoid arthritis who presented for evaluation of incidental thyroid nodules, occasional palpitations, tremors, and mild change in her voice. She denied abnormal weight loss or diarrhea. No history of radiation to the neck and no family history of thyroid disease or thyroid cancer. The thyroid exam showed an enlarged left palpable nodule. Labs significant for TSH 1.6 mIU/L (normal: 0.4-4 mIU/L), FT4 0.8 ng/dl (normal 0.7-1.9 ng/dL) and T3 77ng/dL (normal: 60-180 ng/dL). Thyroid U/S showed left hemiagenesis and right sided nodules biggest is 1.1 cm solid, hypoechoic with coarse calcifications, FNA was recommended and showed follicular lesion of undetermined significance, molecular testing was done and Thyroseq came back intermediate to high risk RAS and EIF1AX positive reflecting a 70 % probability of cancer. Based on these results, surgery was recommended, and the patient underwent right thyroidectomy. Surgery was uncomplicated and despite reported higher risk of hyperparathyroidism patient’s calcium and PTH were normal, and no parathyroid adenomas were identified intraoperatively. The pathology from the thyroidectomy showed follicular adenoma of 1 cm and no malignancy. She was started on Synthroid 100mcg daily post op. Discussion: This case demonstrates a case of a benign thyroid nodule and preserved parathyroid levels in the setting of thyroid hemiagenesis. Usually in THA, the contralateral lobe is at an increased risk for pathology of compensatory hypertrophy or hyperplasia. According to available studies, cancer association with THA was more common in left hemiagenesis and parathyroid adenomas more common ipsilateral to hemiagenesis . Despite Our patient’s FNA revealed atypical findings, molecular testing revealed RAS and EIF1AX positive, marking intermediate to high cancer risk. However, the thyroidectomy pathology report unveiled no evidence of malignancy, contraindicating the anticipated high cancer risk in those with left THA. This case highlights the rarity of THA and different possible presentations and cancer risks. Presentation: 6/2/2024

7443 Severe Hypothyroidism and Adrenal Insufficiency in a 27-Year-Old Male with Klippel-Feil Syndrome: A Case Report

Abstract Disclosure: S. Almardini: None. F. Haddadin: None. L. Aoun: None. F. Saliba: None. J. Zaidan: None. Background: Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by improper segmentation of the cervical vertebrae. The classical clinical triad consists of short neck, low posterior hairline, and limited neck mobility. It is uncommonly associated with endocrine abnormalities. We present a rare case of KFS with severe primary hypothyroidism. Case Presentation: A 27-year-old male with KFS presented for evaluation of profound fatigue and lack of energy. His vital signs revealed a heart rate of 50 and a borderline low blood pressure. On physical exam patient was noted to be lethargic and icteric, thyroid exam was limited due to patient short neck. Labs were consistent with severe hypothyroidism TSH of 825 mIU/L, total T4 <0.4 mcg/dL, low 8 AM cortisol of 4.3 mcg/dL, elevated LDL at 333 mg/dL, elevated liver enzymes AST 491 U/L, ALT 294 U/L, neutropenia with WBC 2.69 x10^3/uL 20% neutrophils and anemia Hb 12 g/dL. TPO and thyroglobulin antibodies were positive at 149.0 and 109.0 IU/mL respectively, 21 hydroxylase antibodies were negative. Thyroid Ultrasound showed small and diffusely heterogenous thyroid. Patient was started on Levothyroxine 125 mcg daily and hydrocortisone with improvement in his symptoms as well as normalization of his lipid panel, liver enzymes and neutropenia. The patient was continued on levothyroxine 125 mcg, hydrocortisone was tapered and repeat cortisol levels were normal. Discussion: This case demonstrates an unusual association between KFS and hypothyroidism secondary to Hashimoto thyroiditis, likely representing an incidental finding rather than a causative relationship. The cervical spinal abnormalities and short neck characteristic of KFS could potentially lead to compression of neurological and vascular structures in the neck. However, this is unlikely to fully explain our patient's hypothyroidism. There are few published case reports of KFS with endocrine disorders in the literature that describe incidental findings like autoimmune thyroiditis and hypoparathyroidism, but there is no known biological mechanism linking KFS and endocrine dysfunction. Moreover, there is no evidence in either our patient's case or in existing literature to suggest a higher occurrence of autoimmune disorders like Hashimoto in such individuals. Conclusion: we present a novel case of KFS found incidentally with primary hypothyroidism. While these endocrine disorders could compound the growth delay and developmental issues typically seen in KFS, they do not appear to be causally related. This case highlights the need to monitor endocrine function in KFS patients and serves as a reminder that common conditions may co-occur simply by chance. Presentation: 6/3/2024

8015 Growth Hormone Axis Dysfunction in PMM2-CDG: Exploring the Role of Dynamic Tests for the Management of Short Stature in Two Pediatric Cases

Abstract Disclosure: G. Del Medico: None. E. Procopio: None. L. Ferri: None. A. Barbato: None. A. Morrone: None. S. Stagi: None. PMM2-CDG is the most prevalent congenital disorder of glycosylation (CDG) and is caused by defective phosphomannomutase2 (PMM2) activity. According to the 2019 guidelines, approximately half of PMM2-CDG patients exhibit short stature and low serum levels of insulin-like growth factor-1 (IGF-1), IGF binding protein 3 (IGFBP3), and acid-labile subunit (ALS). Despite this, there is no expert consensus on the endocrinological management of this condition. We investigated the growth hormone (GH) axis in two 12-year-old female patients with PMM2-CDG. The first patient was compound heterozygote for the most common PMM2 gene variants in Italy, p.(Leu32Arg) and p.(Arg141His). She presented with short stature (< 2 Standard Deviation Score, SDS) and low serum levels of IGF-1 and IGF-BP3 (< 2.5° for age and sex). Bone age was significantly delayed. Tanner stage was prepubertal. Somatotropic response to GH stimulation testing (Levodopa) was normal. After the IGF-1 generation test with recombinant GH, serum IGF-1 increased by 115%. The second patient was compound heterozygote for the known PMM2 pathogenetic variant p.(Ala108Val) and the novel p.(Thr171Asnfs*11) variant (only case described in literature). She presented short stature (< 2 SDS) with near-to-normal IGF-1 and IGF-BP3 serum levels (2.5° for age and sex). Bone age was slightly delayed. Tanner stage was prepubertal. She also exhibited severe obesity, hypertriglyceridemia, and hepatic steatosis. Her somatotropic response to two GH stimulation tests (Levodopa and Arginine) was deficient, probably because of her significant overweight. IGF-1 serum levels didn’t increase after the IGF-1 generation test. Hypoglycosylation in PMM2-CDG impairs the IGF1 system on multiple levels. It destabilizes the ternary complex formed by IGF-1 and glycoproteins IGFBP3 and ALS, therefore reducing the half-life of circulating IGF-1. Hypoglycosylation also reduces IGF1 production by impairing its precursor proIGF-1Ea and its cellular secretion. As a result, PMM2-CDG patients have GH insensitivity, with normal GH production but low levels of IGF-1. However, there is a lack of information in the literature on the use of dynamic tests and hormonal therapies (GH and rhIGF-1) in CDG. The IGF-1 generation test in our patients showed partial GH sensitivity in the first patient and GH insensitivity in the second patient. These observations suggest variability. Some PMM2-CDG patients may benefit from an extended trial with GH therapy, while for GH-insensitive patients a trial with recombinant IGF-1 might be considered. This is one of the first reports that explores the potential role of dynamic tests in PMM2-CDG. As the biochemical effects of hypoglycosylation on the GH-IGF1 pathway are becoming clearer more clinical research is needed to reach a consensus on the management and treatment of short stature in these patients. Presentation: 6/3/2024

Klippel-Feil Syndrome Associated with Sprengel's Syndrome: A Rare Case Report

Klippel-Feil Syndrome (KFS) is a rare congenital disorder characterized by the fusion of cervical vertebrae, often associated with other anomalies such as Sprengel's deformity. We report the case of a 61-year-old female patient presenting with chronic neck pain and paresthesia in the lower limbs, worsened after a minor domestic accident. Cervical CT imaging revealed multisegmental vertebral fusion (C2-C3, C7-T1) and Sprengel’s deformity with an omovertebral bone. This case highlights the importance of early diagnosis and comprehensive imaging, including X-rays, CT scans, and MRIs, for the optimal management of KFS and its associated complications. Awaiting the correction before proceeding with the payment.

Infants with biliary atresia exhibit an altered amino acid profile in their newborn screening.

Biliary atresia (BA) is a rare progressive neonatal cholangiopathy with unknown pathophysiology and time of onset. Newborn Screening (NBS) in Germany is routinely performed in the first days of life to identify rare congenital diseases utilizing dried blood spot (DBS) card analyses. Infants with biliary atresia (BA) are known to have altered amino acid profiles (AAP) at the time point of diagnosis, but it is unclear whether these alterations are present at the time point of NBS. We aimed to analyze amino acid profiles in NBS-DBS of infants with Biliary Atresia. Original NBS-DBS cards of 41 infants who were later on diagnosed with BA were retrospectively obtained. NBS-DBS cards from healthy newborns (n = 40) served as controls. In some BA infants (n = 14) a second DBS card was obtained at time of Kasai surgery. AAP in DBS cards were analyzed by targeted metabolomics. DBS metabolomics in the NBS of at that time point seemingly healthy infants later diagnosed with BA revealed significantly higher levels of Methionine (14.6 ± 8.6μmol/l), Histidine (23.5 ± 50.3μmol/l), Threonine (123.9 ± 72.8μmol/l) and Arginine (14.1 ± 11.8μmol/l) compared to healthy controls (Met: 8.1 ± 2.6μmol/l, His: 18.6 ± 10.1μmol/l, Thr: 98.1 ± 34.3μmol/l, Arg: 9.3 ± 6.6μmol/l). Methionine, Arginine and Histidine showed a further increase at time point of Kasai procedure. No correlation between amino acid levels and clinical course was observed. Our data demonstrate that BA patients exhibit an altered AAP within 72h after birth, long before the infants become symptomatic. This supports the theory of a prenatal onset of the disease and, thus, the possibility of developing a sensitive and specific NBS. Methionine might be particularly relevant due to its involvement in glutathione metabolism. Further investigation of AAP in BA may help in understanding the underlying pathophysiology.

Role and Function of Peroxisomes in Neuroinflammation.

Peroxisomes are organelles involved in many cellular metabolic functions, including the degradation of very-long-chain fatty acids (VLCFAs; C ≥ 22), the initiation of ether-phospholipid synthesis, and the metabolism of reactive oxygen species. All of these processes are essential for the maintenance of cellular lipid and redox homeostasis, and their perturbation can trigger inflammatory response in immune cells, including in the central nervous system (CNS) resident microglia and astrocytes. Consistently, peroxisomal disorders, a group of congenital diseases caused by a block in peroxisomal biogenesis or the impairment of one of the peroxisomal enzymes, are associated with neuroinflammation. Peroxisomal function is also dysregulated in many neurodegenerative diseases and during brain aging, both of which are associated with neuroinflammation. This suggests that deciphering the role of peroxisomes in neuroinflammation may be important for understanding both congenital and age-related brain dysfunction. In this review, we discuss the current advances in understanding the role and function of peroxisomes in neuroinflammation.

8320 Integration of long-read sequencing, DNA methylation and gene expression reveals heterogeneity in Y-chromosome segment lengths in phenotypic males with 46,XX testicular disorder of sex development

Abstract Disclosure: E.B. Johannsen: None. A. Berglund: None. A. Skakkebæk: None. S. Chang: None. J. Rohayem: None. S. Laurentino: None. A. Hørlyck: None. S.O. Drue: None. E.N. Bak: None. J. Fedder: None. F. Tuttelmann: None. J. Gromoll: None. J. Just: None. C.H. Gravholt: None. Background: 46,XX testicular disorder of sex development is a rare congenital condition affecting approximately three per 100,000 newborn males. It is characterized by a combination of the typical female sex chromosome constitution, 46,XX, and a variable male phenotype. In the majority of XX males, a Y chromosome segment containing the sex-determining region gene (SRY) has been translocated to the paternal X chromosome. However, the precise genomic content of the translocated segment, breakpoints, genome-wide effects, and the effect on other biological pathways essential for the phenotype remain unknown. Methods: We performed long-read DNA sequencing (Oxford Nanopore), RNA sequencing (paired-end, 100 bp) and DNA methylation (Infinium EPIC) analysis on blood samples from males with 46,XX testicular disorder of sex development (XX males; n = 11), male controls (46,XY; n = 12 for long-read DNA sequencing, n = 26 for RNA sequencing and DNA methylation) and female controls (46,XX; n = 12 for long-read DNA sequencing, n = 32 for RNA sequencing and DNA methylation), in addition to RNA sequencing and DNA methylation analysis on blood samples from males with Klinefelter syndrome (47,XXY, n = 22). We also performed clinical measures on all XX males and a subset of male controls (n = 10). Results: We identified variation in the translocated Y-chromosome segment of our XX male cohort, allowing for subcategorization into 1) XX males without Y chromosome material (n = 1), 2) those with short Yp arms (breakpoint at 2.7-2.8 Mbp, n = 2), 3) those with medium Yp arms (breakpoint at 7.3 Mbp, n = 1) and 4) those with long Yp arms, including AMELY, TBLY1 deletions, and in some cases PRKY deletions (n = 7). We also identified variable expression of the X-Y homologues PRKY and PRKX, appeared to have balanced expression level resulting in overall equilibrium. The Y-chromosomal transcriptome and methylome were affected, reflecting the Y-chromosome segment length. Genomic changes induced by the translocated Yp segment were evident in the transcriptome and methylome of autosomal and X-chromosomal regions, indicating global effects. Furthermore, the transcriptional changes in XX males correlated with phenotypic traits of the XX males, including lower height, decreased lean mass and smaller testicular size. Conclusion: Integration of long-read DNA sequencing, DNA methylation, and RNA sequencing analysis allowed for the identification of a heterogenous translocation process in XX males that exerted widespread effects on methylation and transcription. Presentation: 6/2/2024

9269 Retrotranscribed sequences, a missing piece in the puzzle of Differences/Disorders of Sex Development with unknown genetic causes

Abstract Disclosure: R.L. Batista: None. N.D. D’Alessandre: None. F.O. Rego: None. G.D. Guardia: None. B. Leitao Braga: None. M.Y. Nishi: None. S. Domenice: None. B.B. Mendonca: None. P.A. Galante: None. Background: The human genome is a complex and dynamic structure. These two characteristics have a major contribution from the Mobile Elements (MEs), which comprise at least 50% of the human genome and are sources of genetic novelties. LINE1 (L1), Alu elements, SVA, and LTR elements (HERVs) are MEs highly frequent in the human genome. MEs can create genomic structural variations with consequent roles in health and diseases. Differences of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual’s sex chromosomes, gonads, or anatomic sex. DSDs are caused by genomic variations in genes involved in gonadal or genital development.Objective: We comprehensively examine the potential contributions of MEs as a source of genetic novelties in genes related to sexual development and in the etiology of 46,XY DSD. Subjects and methods: First, we investigate the potential role of fixed MEs, including L1, Alu elements, and retroCNVs, present in DSD genes using whole exome sequencing (WES) data. By applying bioinformatics tools and appropriate pipelines, we parallelly analyzed local WES data from 443 individuals from our lab and a public database (GnomAD). Second, we seek unfixed (polymorphic or somatically acquired) MEs in WES data from a cohort of 41 unrelated DSD patients with undetermined molecular etiology. We found 2,408 L1 elements, 3,587 Alu elements, and 14 SVAs inserted in 75 out of 81 DSD-related genes (92.6%) of the DSD genes. When examining by element class, we identified 3,587 fixed Alus that affected over 70 DSD genes, resulting in an average of approximately 47 Alu element insertions per gene. For L1 elements, 2,408 fixed elements were found in about 60 genes (∼37 insertions per gene). Subsequently, the number of fixed elements identified in SVAs (n=14) and HERVKs (n=8) decreased significantly. Among these insertions, seven genes were identified harboring one retrocopy each and four genes with two or more retrocopies each. In total, we found 19 retrocopies in 11 DSD genes. That massive presence of mobile elements in DSD genes may suggest an evolutionary contribution of MEs incorporation through evolution in human sexual development. Regarding non-fixed elements, we found two polymorphic events: an L1 insertion into WT1 and an Alu insertion into GTF2F1, two key genes to the DSD development. We also found an L1 insertion in the DNAH2 gene (related to spermatogenic failure and male infertility) and an Alu insertion in the TEX15 gene (related to male infertility in mice). Interestingly, we also identified one somatically acquired retroCNV event in a non-classical DSD gene (CHST8). In summary, our study underscores the significance of MEs as potential sources of genetic innovation in human sexual development and as molecular etiologies of DSD. Presentation: 6/1/2024

9269 Retrotranscribed sequences, a missing piece in the puzzle of Differences/Disorders of Sex Development with unknown genetic causes

Abstract Disclosure: R.L. Batista: None. N.D. D’Alessandre: None. F.O. Rego: None. G.D. Guardia: None. B. Leitao Braga: None. M.Y. Nishi: None. S. Domenice: None. B.B. Mendonca: None. P.A. Galante: None. Background: The human genome is a complex and dynamic structure. These two characteristics have a major contribution from the Mobile Elements (MEs), which comprise at least 50% of the human genome and are sources of genetic novelties. LINE1 (L1), Alu elements, SVA, and LTR elements (HERVs) are MEs highly frequent in the human genome. MEs can create genomic structural variations with consequent roles in health and diseases. Differences of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual’s sex chromosomes, gonads, or anatomic sex. DSDs are caused by genomic variations in genes involved in gonadal or genital development.Objective: We comprehensively examine the potential contributions of MEs as a source of genetic novelties in genes related to sexual development and in the etiology of 46,XY DSD. Subjects and methods: First, we investigate the potential role of fixed MEs, including L1, Alu elements, and retroCNVs, present in DSD genes using whole exome sequencing (WES) data. By applying bioinformatics tools and appropriate pipelines, we parallelly analyzed local WES data from 443 individuals from our lab and a public database (GnomAD). Second, we seek unfixed (polymorphic or somatically acquired) MEs in WES data from a cohort of 41 unrelated DSD patients with undetermined molecular etiology. We found 2,408 L1 elements, 3,587 Alu elements, and 14 SVAs inserted in 75 out of 81 DSD-related genes (92.6%) of the DSD genes. When examining by element class, we identified 3,587 fixed Alus that affected over 70 DSD genes, resulting in an average of approximately 47 Alu element insertions per gene. For L1 elements, 2,408 fixed elements were found in about 60 genes (∼37 insertions per gene). Subsequently, the number of fixed elements identified in SVAs (n=14) and HERVKs (n=8) decreased significantly. Among these insertions, seven genes were identified harboring one retrocopy each and four genes with two or more retrocopies each. In total, we found 19 retrocopies in 11 DSD genes. That massive presence of mobile elements in DSD genes may suggest an evolutionary contribution of MEs incorporation through evolution in human sexual development. Regarding non-fixed elements, we found two polymorphic events: an L1 insertion into WT1 and an Alu insertion into GTF2F1, two key genes to the DSD development. We also found an L1 insertion in the DNAH2 gene (related to spermatogenic failure and male infertility) and an Alu insertion in the TEX15 gene (related to male infertility in mice). Interestingly, we also identified one somatically acquired retroCNV event in a non-classical DSD gene (CHST8). In summary, our study underscores the significance of MEs as potential sources of genetic innovation in human sexual development and as molecular etiologies of DSD. Presentation: 6/1/2024

The pivotal role of neurosurgeons in transitional care: A comprehensive tertiary healthcare institution's experience.

Transitional care (TC) is increasingly crucial, particularly in neurosurgery, where optimal follow-through of patients' care is paramount. Challenges of transition are exacerbated by the complexity of neurosurgical conditions, with pediatric and adult neurosurgery often managed separately by different attending neurosurgeons or in different institutions. While numerous models for transitioning have been proposed, several barriers persist, impeding successful transfer from pediatric to adult settings. Our review focuses on important roles neurosurgeons can play in facilitating successful transition, exploring some existing TC models, with emphasis on the benefits of maintaining a single provider. Clinic visits data between 2019 to 2023 of patients between the ages of 16 to 26 was compiled retrospectively. Successful transition was defined as continued follow-up moving from pediatric to adulthood with lost to follow-up being that of unsuccessful transition. Age, diagnosis and whether patients were successfully transitioned or lost to follow-up were documented. 1829 neurosurgical patients between the ages of 16 to 26 were identified over 5 years. A snapshot review identified 78 adolescent patients deemed to require follow-up into adulthood. 13 patients had epilepsy, 32 central nervous system (CNS) tumors, 17 congenital conditions, 14 neurovascular, and 2 patients had idiopathic intracranial hypertension. All 78 were noted to have successfully transited into their adulthood (age 21 and beyond). Having the same providers; having pediatric and adult neurosurgery within the same institution, was the single most important factor in facilitating successful transition. Neurosurgeons in institutions, particularly those with experience and competencies in both pediatric and adult care, can serve as crucial anchors during the transitional period. At our institution, the implementation of this continuity of care model has demonstrated remarkable success. Institutions with both pediatric and adult services would be uniquely positioned to develop and implement effective transitional care.

8703 Retrotranscribed sequences, a missing piece in the puzzle of Differences/Disorders of Sex Development with unknown genetic causes

Abstract Disclosure: R.L. Batista: None. N.D. D’Alessandre: None. F.O. Rego: None. G.D. Guardia: None. B. Leitao Braga: None. M.Y. Nishi: None. S. Domenice: None. B.B. Mendonca: None. P.A. Galante: None. Background: The human genome is a complex and dynamic structure. These two characteristics have a major contribution from the Mobile Elements (MEs), which comprise at least 50% of the human genome and are sources of genetic novelties. LINE1 (L1), Alu elements, SVA, and LTR elements (HERVs) are MEs highly frequent in the human genome. MEs can create genomic structural variations with consequent roles in health and diseases. Differences of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual’s sex chromosomes, gonads, or anatomic sex. DSDs are caused by genomic variations in genes involved in gonadal or genital development.Objective: We comprehensively examine the potential contributions of MEs as a source of genetic novelties in genes related to sexual development and in the etiology of 46,XY DSD. Subjects and methods: First, we investigate the potential role of fixed MEs, including L1, Alu elements, and retroCNVs, present in DSD genes using whole exome sequencing (WES) data. By applying bioinformatics tools and appropriate pipelines, we parallelly analyzed local WES data from 443 individuals from our lab and a public database (GnomAD). Second, we seek unfixed (polymorphic or somatically acquired) MEs in WES data from a cohort of 41 unrelated DSD patients with undetermined molecular etiology. We found 2,408 L1 elements, 3,587 Alu elements, and 14 SVAs inserted in 75 out of 81 DSD-related genes (92.6%) of the DSD genes. When examining by element class, we identified 3,587 fixed Alus that affected over 70 DSD genes, resulting in an average of approximately 47 Alu element insertions per gene. For L1 elements, 2,408 fixed elements were found in about 60 genes (∼37 insertions per gene). Subsequently, the number of fixed elements identified in SVAs (n=14) and HERVKs (n=8) decreased significantly. Among these insertions, seven genes were identified harboring one retrocopy each and four genes with two or more retrocopies each. In total, we found 19 retrocopies in 11 DSD genes. That massive presence of mobile elements in DSD genes may suggest an evolutionary contribution of MEs incorporation through evolution in human sexual development.Regarding non-fixed elements, we found two polymorphic events: an L1 insertion into WT1 and an Alu insertion into GTF2F1, two key genes to the DSD development. We also found an L1 insertion in the DNAH2 gene (related to spermatogenic failure and male infertility) and an Alu insertion in the TEX15 gene (related to male infertility in mice). Interestingly, we also identified one somatically acquired retroCNV event in a non-classical DSD gene (CHST8). In summary, our study underscores the significance of MEs as potential sources of genetic innovation in human sexual development and as molecular etiologies of DSD. Presentation: 6/1/2024

8320 Integration of long-read sequencing, DNA methylation and gene expression reveals heterogeneity in Y-chromosome segment lengths in phenotypic males with 46,XX testicular disorder of sex development

Abstract Disclosure: E.B. Johannsen: None. A. Berglund: None. A. Skakkebæk: None. S. Chang: None. J. Rohayem: None. S. Laurentino: None. A. Hørlyck: None. S.O. Drue: None. E.N. Bak: None. J. Fedder: None. F. Tuttelmann: None. J. Gromoll: None. J. Just: None. C.H. Gravholt: None. Background: 46,XX testicular disorder of sex development is a rare congenital condition affecting approximately three per 100,000 newborn males. It is characterized by a combination of the typical female sex chromosome constitution, 46,XX, and a variable male phenotype. In the majority of XX males, a Y chromosome segment containing the sex-determining region gene (SRY) has been translocated to the paternal X chromosome. However, the precise genomic content of the translocated segment, breakpoints, genome-wide effects, and the effect on other biological pathways essential for the phenotype remain unknown. Methods: We performed long-read DNA sequencing (Oxford Nanopore), RNA sequencing (paired-end, 100 bp) and DNA methylation (Infinium EPIC) analysis on blood samples from males with 46,XX testicular disorder of sex development (XX males; n = 11), male controls (46,XY; n = 12 for long-read DNA sequencing, n = 26 for RNA sequencing and DNA methylation) and female controls (46,XX; n = 12 for long-read DNA sequencing, n = 32 for RNA sequencing and DNA methylation), in addition to RNA sequencing and DNA methylation analysis on blood samples from males with Klinefelter syndrome (47,XXY, n = 22). We also performed clinical measures on all XX males and a subset of male controls (n = 10). Results: We identified variation in the translocated Y-chromosome segment of our XX male cohort, allowing for subcategorization into 1) XX males without Y chromosome material (n = 1), 2) those with short Yp arms (breakpoint at 2.7-2.8 Mbp, n = 2), 3) those with medium Yp arms (breakpoint at 7.3 Mbp, n = 1) and 4) those with long Yp arms, including AMELY, TBLY1 deletions, and in some cases PRKY deletions (n = 7). We also identified variable expression of the X-Y homologues PRKY and PRKX, appeared to have balanced expression level resulting in overall equilibrium. The Y-chromosomal transcriptome and methylome were affected, reflecting the Y-chromosome segment length. Genomic changes induced by the translocated Yp segment were evident in the transcriptome and methylome of autosomal and X-chromosomal regions, indicating global effects. Furthermore, the transcriptional changes in XX males correlated with phenotypic traits of the XX males, including lower height, decreased lean mass and smaller testicular size. Conclusion: Integration of long-read DNA sequencing, DNA methylation, and RNA sequencing analysis allowed for the identification of a heterogenous translocation process in XX males that exerted widespread effects on methylation and transcription. Presentation: 6/2/2024

8703 Retrotranscribed sequences, a missing piece in the puzzle of Differences/Disorders of Sex Development with unknown genetic causes

Abstract Disclosure: R.L. Batista: None. N.D. D’Alessandre: None. F.O. Rego: None. G.D. Guardia: None. B. Leitao Braga: None. M.Y. Nishi: None. S. Domenice: None. B.B. Mendonca: None. P.A. Galante: None. Background: The human genome is a complex and dynamic structure. These two characteristics have a major contribution from the Mobile Elements (MEs), which comprise at least 50% of the human genome and are sources of genetic novelties. LINE1 (L1), Alu elements, SVA, and LTR elements (HERVs) are MEs highly frequent in the human genome. MEs can create genomic structural variations with consequent roles in health and diseases. Differences of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual’s sex chromosomes, gonads, or anatomic sex. DSDs are caused by genomic variations in genes involved in gonadal or genital development.Objective: We comprehensively examine the potential contributions of MEs as a source of genetic novelties in genes related to sexual development and in the etiology of 46,XY DSD. Subjects and methods: First, we investigate the potential role of fixed MEs, including L1, Alu elements, and retroCNVs, present in DSD genes using whole exome sequencing (WES) data. By applying bioinformatics tools and appropriate pipelines, we parallelly analyzed local WES data from 443 individuals from our lab and a public database (GnomAD). Second, we seek unfixed (polymorphic or somatically acquired) MEs in WES data from a cohort of 41 unrelated DSD patients with undetermined molecular etiology. We found 2,408 L1 elements, 3,587 Alu elements, and 14 SVAs inserted in 75 out of 81 DSD-related genes (92.6%) of the DSD genes. When examining by element class, we identified 3,587 fixed Alus that affected over 70 DSD genes, resulting in an average of approximately 47 Alu element insertions per gene. For L1 elements, 2,408 fixed elements were found in about 60 genes (∼37 insertions per gene). Subsequently, the number of fixed elements identified in SVAs (n=14) and HERVKs (n=8) decreased significantly. Among these insertions, seven genes were identified harboring one retrocopy each and four genes with two or more retrocopies each. In total, we found 19 retrocopies in 11 DSD genes. That massive presence of mobile elements in DSD genes may suggest an evolutionary contribution of MEs incorporation through evolution in human sexual development.Regarding non-fixed elements, we found two polymorphic events: an L1 insertion into WT1 and an Alu insertion into GTF2F1, two key genes to the DSD development. We also found an L1 insertion in the DNAH2 gene (related to spermatogenic failure and male infertility) and an Alu insertion in the TEX15 gene (related to male infertility in mice). Interestingly, we also identified one somatically acquired retroCNV event in a non-classical DSD gene (CHST8). In summary, our study underscores the significance of MEs as potential sources of genetic innovation in human sexual development and as molecular etiologies of DSD. Presentation: 6/1/2024

Prenatal ultrasound detection of fetal amniotic band ingestion in monochorionic diamniotic twin pregnancy: a rare case report

BackgroundAmniotic Band Syndrome (ABS) is a rare congenital condition characterized by the formation of fibrous bands within the amniotic sac that can entangle and restrict fetal development, leading to various deformities. In this report, we present an unprecedented case of fetal amniotic band ingestion in a monochorionic diamniotic (MCDA) twin pregnancy. Reporting this case is essential for expanding the understanding of the diverse presentations of amniotic bands, considering this rare entity in the differential diagnosis of prenatal ultrasound findings, and emphasizing the importance of vigilant prenatal monitoring and individualized management strategies.Case PresentationA 35-year-old gravida 2, para 1 woman with an MCDA twin pregnancy experienced an uneventful pregnancy until the 33rd week, when routine ultrasonography revealed mild intrauterine growth restriction in both twins. At 35 weeks and 5 days gestation, the patient presented with mild abdominal pain. An emergency ultrasound revealed that Twin A ingested an amniotic band. Despite the absence of overt fetal distress, a comprehensive risk assessment was conducted, taking into account potential complications, such as airway obstruction and gastrointestinal issues due to prolonged amniotic band ingestion. Considering the risks versus the benefits of continued gestation and the near-term status, an emergency cesarean section was performed. The procedure resulted in the successful delivery of both twins with satisfactory Apgar scores. A 9-cm fibrous strand was promptly extracted from Twin A’s oral cavity after delivery, confirming prenatal diagnosis. Both neonates underwent thorough examinations, revealing no additional anomalies, and demonstrated normal development during the nine-month follow-up.ConclusionThis case highlights the inherent challenges in diagnosing and managing the rare presentations of amniotic band-related complications, particularly in MCDA twin pregnancies. The instance of fetal amniotic band ingestion underscores the vital role of comprehensive prenatal imaging in ensuring accurate diagnosis and tailoring individualized risk assessments throughout the pregnancy in such rare and complex situations.

CFTR Exon 10 deleterious mutations in patients with congenital bilateral absence of vas deferens in a cohort of Pakistani patients.

Congenital bilateral absence of vas deferens (CBAVD) is a urological syndrome of Wolffian ducts and is responsible for male infertility and obstructive azoospermia. This study is designed to explore the integrity of exon 10 of CFTR and its role in male infertility in a cohort of CBVAD patients in Pakistan. Genomic DNA was extracted from 17 male patients with CBAVD having clinical symptoms, and 10 healthy controls via phenol-chloroform method. Exon 10 of the CFTR gene was amplified, using PCR with specific primers and DNA screening was done by Sanger sequencing. Sequencing results were analyzed using freeware Serial Cloner, SnapGene, BioEdit and FinchTV. Furthermore, bioinformatics tools were used to analyze the mutations and their impact on the protein function and stability. We have identified 4 mutations on exon 10 of CFTR in 6 out of 17 patients. Two of the mutations were missense variants V456A, K464E, and the other two were silent mutations G437G, S431S. The identified variant V456A was present in 4 of the studied patients. Whereas, the presence of K464E in our patients further weighs on the crucial importance for its strategic location to influence the gene function at post-transcriptional and protein level. Furthermore, Polyphen-2 and SIFT analyze the mutations as harmful and deleterious. The recurrence of V456A and tactically conserved locality of K464E are evidence of their potential role in CBAVD patients and in male infertility. The data can contribute in developing genetic testing and treatment of CBAVD.

Potential Development in Knowledge, Chest Compression Skill, Automated External Defibrillator Skill and Basic Life Support for Thai Village Health Volunteer

Background and objectives: Currently, emergencies from complications, congenital disease, or physical pathology, such as out-of-hospital cardiac arrest (OHCA), are important causes of death and hospital admission, and sudden cardiac arrest occurs until the heart stops working immediately. This study aims to To examine the results of repeated measurements with Qualitative Confirmation of results, knowledge, understanding, chest compression skills, use of AEDs, and basic life support for village health volunteers (VHV). Methods: This mixed-method. Phase 1 quasi-experimental research. The sample group consisted of 30 Village Health Volunteers (VHV) selected using a simple random sampling method. The tool used in this research was the basic life support program that seduces a group process. Knowledge assessment form and basic life support skills. Data collection was performed by repeated measurement six times; Phase 2, qualitative research by discussing Basic life support program of Village Health Volunteers (VHV) that participated in the quantitative research program. After the 6th follow-up repeat measurement for one month, the sample was selected randomly from 10 participants in the program in phase 1. Quantitative data were analyzed using descriptive statistics, one-way analysis ANOVA with repeated measures, and statistical data. Qualitative data were analyzed using content analysis. Results: The findings of the quantitative study showed that Village Health Volunteer (VHV) had knowledge scores on patient assessment and environment, chest compression, use of AED, and basic life support. From each measurement, there was a better direction statistically significant at the qualitative level of 0.01. Conclusion: Basic life support program using group processes can develop potential and increase confidence in knowledge and understanding, skills in patient assessment and environment, chest compression, use of AED, and basic life support. Therefore, knowledge, understanding, and basic life support skills should be regularly and continuously reviewed to ensure resuscitation efficiency. Word count: 5,578 words, excluding references. Funding Statement: The study was supported by a grant from Non Sung Hospital, Nakhon Ratchasima Province, Thailand. Conflict of Interest declaration: The authors declare that they have NO affiliations with or involvement in any organization or entity with any financial interest in the subject matter or materials discussed in this manuscript. Author Contributions: AV and PC contributed to the design and implementation of the research, JK and KV to the analysis of the results, and TB and TP to the writing of the manuscript.