Pathogenic Variants Research Articles

Immune-Mediated Megaconial Myopathy: A Novel Subtype of Autoimmune Myopathy.

To describe a novel subtype of autoimmune myopathy, immune-mediated megaconial myopathy (IMMM), myopathologically characterized by giant mitochondria (megaconia). In this case series, we reviewed the Mayo Clinic Muscle Pathology database, between 2018 and 2023, to identify patients with megaconial pathology, subacute progressive weakness, and hyperCKemia, clinically resembling myositis. We recruited 1 patient from another institute, who had similar clinicopathologic features. Five patients were identified. Age at onset of weakness ranged from 19 to 45.5 years. All patients had proximal weakness, elevated creatine kinase levels (1,214 to 5,920 U/L), negative myositis antibodies, necrotizing myopathology, and nonnecrotic myofibers harboring giant mitochondria. Immunohistochemical studies conducted in 4 patients showed sarcolemmal MHC-1 and C5b9 immunoreactivities. Megaconial pathology was considered pathognomonic of congenital muscular dystrophy due to biallelic pathogenic variants in CHKB. Sequencing of CHKB in 4/5 patients was unrevealing. Immunomodulatory therapy improved weakness and hyperCKemia in 4 treated patients. Of interest, all patients had coexisting pancreatic diseases (3 cystic fibrosis-related exocrine pancreatic insufficiency, 1 pancreatic cancer, and 1 pancreatitis). In addition to incurable CHKB-congenital muscular dystrophy, giant mitochondria can also occur in this new subtype of treatable autoimmune myopathy, IMMM. The association between IMMM and pancreatic disorders remains to be elucidated.

Unprecedented Co-occurrence: Identification of a Pathogenic Genetic Variant in the KMT2B Gene in a Wilson Disease Patient with a Pathogenic ATP7B Mutation

The pathophysiology of dystonia in Wilson disease (WD) is complex and poorly understood. Copper accumulation in the basal ganglia, disrupts dopaminergic pathways, contributing to dystonia’s development via neurotransmitter imbalance. Despite advances in diagnosis and management, WD with dystonia remains a challenging condition to treat. We aim to report the unprecedented co-occurrence of pathogenic genetic variants in both the ATP7B and KMT2B genes in a patient with WD. A 13-year-old male presented at 12 with dysarthria and bilateral Kayser-Fleischer rings. Over months, dystonia spread to his left foot, upper limb, and trunk, accompanied by slowed daily activities. Diagnostic tests included MRI for brain structure, abdominal ultrasound for liver function, serum ceruloplasmin and copper levels to assess copper metabolism, and 24-hour urine copper tests for excretion levels. Whole exome sequencing was conducted using genomic DNA from peripheral blood samples. Variant classification followed guidelines from the American College of Medical Genetics and Genomics. The sequencing revealed compound heterozygous pathogenic variants in the ATP7B gene: NM_000053.4:c.2165dupT and NM_000053.4:c.813C>A. A pathogenic variant in the KMT2B gene, NM_014727:c.3052delA, was identified. This case highlights WD co-occurrence with ATP7B and KMT2B mutations, suggesting KMT2B as a potential genetic modifier.

Cyclin‐dependent kinase 13 is indispensable for normal mouse heart development

AbstractCongenital heart disease (CHD) has an incidence of approximately 1%. Over the last decade, sequencing studies including large cohorts of individuals with CHD have begun to unravel the genetic mechanisms underpinning CHD. This includes the identification of variants in cyclin‐dependent kinase 13 (CDK13), in individuals with syndromic CHD. CDK13 encodes a serine/threonine protein kinase. The cyclin partner of CDK13 is cyclin K; this complex is thought to be important in transcription and RNA processing. Pathogenic variants in CDK13 cause CDK13‐related disorder in humans, characterised by intellectual disability and developmental delay, recognisable facial features, feeding difficulties and structural brain defects, with 35% of individuals having CHD. To obtain a greater understanding for the role that this essential protein kinase plays in embryonic heart development, we have analysed a presumed loss of function Cdk13 transgenic mouse model (Cdk13tm1b). The homozygous mutants were embryonically lethal in most cases by E15.5. X‐gal staining showed Cdk13 expression localised to developing facial regions, heart and surrounding areas at E10.5, whereas at E12.5, it was more widely present. In the E15.5 heart, staining was seen throughout. RT‐qPCR showed significant reduction in Cdk13 transcript expression in homozygous compared with WT and heterozygous hearts at E10.5 and E12.5. Detailed morphological 3D analysis of embryonic and postnatal hearts was performed using high‐resolution episcopic microscopy, which affords a more detailed analysis of structures such as cardiac valve leaflets and endocardial cushions, compared with more traditional histological techniques. We show that both the homozygous and heterozygous Cdk13tm1b mutants exhibit a range of CHD, including ventricular septal defects, bicuspid aortic valve, double outlet right ventricle and atrioventricular septal defects. 100% (n = 4) of homozygous hearts displayed CHD. Differential expression was seen in Cdk13tm1b homozygous mutants for two genes known to be necessary for normal heart development. The types of defects, and the presence of CHD in heterozygous mice (17.02%, n = 8/47), are consistent with the CDK13‐related disorder phenotype in humans. This study provides important insights into the effects of reduced function of CDK13 in the mouse heart and contributes to our understanding of the mechanism behind this disorder as a cause of CHD.

Linking CDH1 SNPs to gastric cancer risk: a comprehensive analysis of rs16260, rs13689, and rs9929218.

Single nucleotide polymorphisms (SNPs) are linked to carcinogenesis. Pathogenic variants in the CDH1 gene are associated with gastric cancer. This study examines the genotype and allele frequencies of three SNPs (rs16260, rs13689, and rs9929218) in the CDH1 gene and their relationship with gastric cancer risk. The study involved 105 gastric cancer patients with pathology results and 105 healthy controls. Clinical, histopathological, and demographic data were collected and compared between the two groups. No significant differences were found for rs16260 (-160 C > A) and rs9929218 (G > A) between patients and controls (p > 0.05). For rs13689 (T > C), the T allele frequency was 90% in patients versus 69% in controls, while the C allele frequency was 10% in patients versus 31% in controls. A significant difference was observed for this SNP, with a higher T allele frequency in patients (OR = 4.03 CI95% 2.4-6.7, p < 0.0001) compared with controls, suggesting a fourfold increased risk of gastric cancer. Genotype frequencies were 80% wild-type (TT) and 20% heterozygous-type (TC) in patients, and 58% TT, 22% TC, and 20% mutant-type (CC) in controls (p < 0.0001). The frequencies of non-C allele carriers (TT) were present in 80% of patients versus 58.1% of controls (OR = 2.88 CI95% 1.56-5.34, p = 0.0006). This study is the first to link the rs13689 SNP's T allele and TT genotype with increased gastric cancer risk. Our results suggest that thers13689 T allele may contribute significantly to disease susceptibility, while thers16260 CC genotype and rs9929218 GG genotype may influence risk in smokers.

De Novo RB1 Germline Variant in Retinoblastoma with Two Subsequent Independent Neoplasms: Case Report and Literature Review

Variants in the RB1 gene are associated with retinoblastoma (RB) development, and their presence in germline cells considerably increases the risk of subsequent malignant neoplasms (SMNs) in RB survivors. We report a female patient with bilateral RB who developed two SMNs in less than ten years, with a de novo pathogenic nonsense variant in RB1 [NM_000321.3:c.306T&gt;A, p.(Cys102*)] in heterozygosity. The updated literature review of similar cases of SMN in patients with a previous diagnosis of RB reveals a wide range in both the type of subsequent malignancy and the age at which these SMNs develop. In addition, we identified only three cases with two SMNs following RB diagnosis, with at least one of these being an EWS. This case broadens the clinical and genetic landscape of RB, demonstrates the importance of a multidisciplinary approach in these patients, and highlights genetic diagnosis as a mandatory feature for management.

Germline BRCA1/2 status and chemotherapy response score in high-grade serous ovarian cancer.

High-grade serous ovarian cancer (HGSOC) can be treated with platinum-based neoadjuvant chemotherapy (NACT) and delayed primary surgery (DPS). Histopathological response to NACT can be assessed using Böhm's chemotherapy response score (CRS). We investigated whether germline BRCA1/2 (gBRCA1/2) genotype associated with omental CRS phenotype. A retrospective study of patients with newly diagnosed FIGO stage IIIC/IV HGSOC prescribed NACT and tested for gBRCA1/2 pathogenic variants (PVs) between September 2017 and December 2022 at The Christie Hospital. The Cox proportional hazards model evaluated the association between survival and key clinical factors. The chi-square test assessed the association between CRS3 (no/minimal residual tumour) and gBRCA1/2 status. Of 586 eligible patients, 393 underwent DPS and had a CRSreported. Independent prognostic factors by multivariable analysis were gBRCA1/2 status (PV versus wild type [WT]), CRS (3 versus 1 + 2), surgical outcome (complete versus optimal/suboptimal) and first-line poly (ADP-ribose) polymerase-1/2 inhibitor maintenance therapy (yes versus no) (all P < 0.05). There was a non-significant trend for tumours with a gBRCA2 PV having CRS3 versus WT (odds ratio [OR] = 2.13, 95% confidence intervals [CI] 0.95-4.91; P = 0.0647). By contrast, tumours with a gBRCA1 PV were significantly less likely to have CRS3 than WT (OR = 0.35, 95%CI 0.14-0.91; P = 0.0291). Germline BRCA1/2 genotype was not clearly associated with superior omental CRS. Further research is required to understand how HGSOC biology defines CRS.

Genetic, Clinical, and Biochemical Characterization ofa Large Cohort of Palestinian Patients With Fanconi-Bickel Syndrome.

This study aims to investigate the clinical, biochemical, and genetic characteristics of Fanconi-Bickel syndrome (FBS) in a cohort of 20 individuals from Palestine and to identify novel pathogenic variants. A retrospective analysis was conducted on medical records from Al-Makassed Hospital's pediatric department spanning 2015 to 2023. Individuals diagnosed with FBS via molecular genetic testing were included in the study. Among the 20 genetically confirmed FBS patients, hepatomegaly was prevalent in 95%, whereas 70% exhibited both developmental delay and hypophosphatemic rickets, and 68.4% experienced growth retardation. Hypertriglyceridemia (HTG) was universal. Elevated liver enzymes and alkaline phosphatase were common, along with hypophosphatemia (95%) and urinary abnormalities. Genetic analysis revealed five distinct SLC2A2 pathogenic variants, including three previously unreported variants: p.Gln23Arg (c.68A > G), p.Thr353Arg (c.1058_1059delinsGG), and an exon 7 deletion. This study presents the largest single-center cohort of FBS patients, expanding our understanding of the disorder's phenotypic and genotypic spectrum. Despite FBS generally carrying a favorable prognosis, timely diagnosis remains crucial to prevent severe complications.

Acral Peeling Skin Syndrome: A Rare Skin Disorder

Objective − We report the case of an 8-year-old girl with acral peeling skin syndrome.Case Report − A previously healthy 8-yearold girl presented with a history of flaccid bullous lesions on the plantar surface of her feet, and subsequent peeling and scarring since she was 12 months old. A biopsy of the plantar lesion was carried out and histological examination revealed an acral skin flap characterized only by the presence of an intracorneal bullous cleft, with hypogranulosis and focal parakeratosis. A genetic study was carried out, identifying two pathogenic heterozygous variants in the TGM5 gene. The clinical presentation, histological and genetic examination confirmed the diagnosis of acral peeling skin syndrome.Conclusion − Acral peeling skin syndrome is not a widely known pathology, which means that cases of acral peeling skin syndrome can be misdiagnosed as Epidermolysis bullosa simplex, especially when a genetic study is not available. Particularly in younger children, it is important not to underestimate the diagnosis of acral peeling skin syndrome, given the different prognostic implications between the two diagnoses.

A series of genetically confirmed congenital lipodystrophy and diabetes in adult southern Indian patients.

In this study, we analysed the mutation spectrum in subjects with suspected lipodystrophy using a targeted Next-generation sequencing (NGS) approach. Subjects with suspected lipodystrophy were for screened six genes (AGPAT2, BSCL2, LMNA, PPARG, ZMPSTE24, INSR) and the variants identified were confirmed through Sanger sequencing. The clinical and biochemical parameters were compared among the mutation positive and negative subjects. We identified eight individuals with pathogenic or likely pathogenic mutations, including both homozygous and heterozygous variants. Homozygous variants included AGPAT2(NM_006412.4):c.493-2A>G, AGPAT2(NM_006412.4):c.254_258dup, and BSCL2(NM_001122955.4):c.570del, while heterozygous variants encompassed LMNA(NM_170707.4):c.1444C>T, LMNA(NM_170707.4):c.1456A>G, LMNA(NM_170707.4):c.1445G>A, and PPARG(NM_015869.5):c.949T>C mutations. In this cohort, three subjects were diagnosed with congenital generalized lipodystrophy, while the remaining five had familial partial lipodystrophy. Majority (7/8) of the patients with lipodystrophy had hepatic involvement. Notably, more than half of the subjects (5/8) achieved optimal glycemic control through insulin sensitizers (PPARγ agonist and Metformin). Interestingly, even with a limited gene panel test, mutation-positive individuals exhibited a higher prevalence of typical clinical features and biochemical characteristics associated with lipodystrophy compared to their mutation-negative counterparts. In subjects with lipodystrophy, targeted NGS based screening may establish a genetic diagnosis and aid in family screening and genetic counselling. Knowing the clinical and biochemical features typical to lipodystrophy may help in diagnosis especially in resource limited setting.

Hearing impairment and vestibular function in patients with a pathogenic splice variant in the LHX3 gene.

LHX3 is a gene encoding a LIM-homeodomain transcription factor important for the fetal development of several organs, such as the pituitary gland, spinal motor neurons and the inner ear. Pathogenic and likely pathogenic variants in the LHX3 gene are infrequent and result in a rare syndrome known as combined pituitary hormone deficiency-3, CPHD3. We have studied hearing and vestibular functions in a group of eight individuals, aged 8-36years, all of whom were homozygous for a specific variant in the LHX3 gene at chromosome 9q34. We reexamined the results of consecutive hearing tests from newborn until April 2024. Our data showed that all the tested patients had progressive sensorineural hearing deficiency ranging from moderately severe to complete loss. We have performed vestibular testing in six patients and, for the first time, demonstrated that a mutation in the LHX3 gene not only affects hearing, but is also associated with vestibular impairment. The human pathogenic variant c.455-2A > G in the LHX3 gene on chromosome 9q34, which present as a founder mutation in the population in northern Sweden, is responsible for phenotypes associated with progressive hearing loss and balance impairment. These findings prove that the LHX3 gene is crucial for the function of both the cochlear and vestibular organs.

Germline pathogenic variants in RNF43 in patients with and without serrated polyposis syndrome.

Serrated Polyposis Syndrome (SPS) is characterized by multiple and/or large serrated polyps in the colon and an increased risk of colorectal cancer (CRC). The etiology is largely unknown, but in a subset of patients with SPS, monoallelic pathogenic variants in RNF43 are detected. To date, however, the penetrance and phenotypic spectrum of patients carrying pathogenic variants (PV) in RNF43 are poorly described. We present eight patients both with and without serrated polyps from four unrelated families with likely pathogenic variants (LPV) in RNF43 and compare the results to current literature. The patients were referred to genetic counseling due to suspicion of hereditary cancer. They underwent genetic testing with custom NGS gene panels including RNF43 as part of a routine genetic work-up. Three LPVs, one multi-exon deletion and two nonsense variants, were detected in four families. Family I had a history of CRC and serrated polyps, but in the three other families (II‒IV) there was no history of CRC or serrated polyps. Colonoscopies in the probands of these families did not reveal any serrated polyps and/or CRC despite some of them being relatively old. Our findings suggest that the penetrance of RNF43-related disease is much lower than previously thought, and raise questions about the connection between RNF43 and disease. The results highlight the complexity of genetic counseling in RNF43 positive families- particularly in families without polyposis. Further research is needed to elucidate the role of RNF43 in the risk of SPS and CRC.

Germline Variant Spectrum in Southern Italian High-Risk Hereditary Breast Cancer Patients: Insights from Multi-Gene Panel Testing

Hereditary breast cancer accounts for 5–10% of all cases, with pathogenic variants in BRCA1/2 and other susceptibility genes playing a crucial role. This study elucidates the prevalence and spectrum of germline variants in 13 cancer predisposition genes among high—risk hereditary breast cancer patients from Southern Italy. We employed next-generation sequencing (NGS) to analyze 254 individuals selected through genetic counseling. Pathogenic or likely pathogenic variants were identified in 13% (34/254) of patients, with 54% of these variants occurring in non-BRCA1/2 genes. Notably, we observed a recurrent BRCA1 c.4964_4982del founder mutation, underscoring the importance of population-specific genetic screening. The spectrum of variants extended beyond BRCA1/2 to include PALB2, ATM, TP53, CHEK2, and RAD51C, highlighting the genetic heterogeneity of breast cancer susceptibility. Variants of uncertain significance were detected in 20% of patients, emphasizing the ongoing challenge of variant interpretation in the era of multi-gene panel testing. These findings not only enhance our understanding of the genetic landscape of breast cancer in Southern Italy but also provide a foundation for developing more targeted, population-specific approaches to genetic testing and counseling, ultimately contributing to the advancement of precision medicine in oncology.

BRCAIndica: a resource for ACMG/AMP classified BRCA1 and BRCA2 variants.

As genetic testing becomes increasingly accessible and affordable, the uniform and accurate interpretation of genetic variants becomes essential. The ACMG/AMP joint guidelines provide the basis for systematic and uniform interpretation of pathogenicity of genetic variants. However, the application of these in routine clinical interpretation at-scale has largely been limited by the lack of resources providing harmonized data especially at a population-scale. Here we describe BRCAIndica, a resource for BRCA1 and BRCA2 variants conforming to the ACMG & AMP joint guidelines to aid uniform clinical interpretation of genetic tests with a specific focus on variants reported in the Indian population. We collected and harmonized variants from across several resources including population-scale datasets, literature survey and other variant datasets. We then classified them according to the ACMG/AMP guidelines.We have collected a total of 10,490 unique variants, of which 2261 Pathogenic and 43 Likely Pathogenic variants belong to BRCA1 and 2694 Pathogenic and 20 Likely Pathogenic variants to BRCA2 respectively. BRCAIndica can be accessed at:https://clingen.igib.res.in/brcaindica/ . In conclusion, BRCAIndica is a powerful resource that offers researchers and clinicians with ACMG/AMP annotated BRCA variants.

Mainstreaming cancer genetics: feasibility of an advanced nurse practitioner-led service diagnosing Lynch syndrome from colorectal cancer in Ireland.

Colorectal cancer (CRC) is a common cancer in Ireland. Of all CRCs, 2-4% are attributable to Lynch Syndrome (LS), the most common CRC predisposition syndrome. LS is caused by constitutional pathogenic variants (PVs) affecting mismatch repair (MMR) genes with resultant MMR protein deficiency (dMMR). Screening of all CRCs with MMR immunohistochemistry (IHC) testing is advocated to increase the detection of LS. However, successful implementation requires appropriate downstream management. In Ireland the traditional pathway involves referral to cancer genetics services to assess eligibility for genetic testing. Cancer genetics services in Ireland face many challenges in providing uniform access to timely healthcare with current wait times for assessment in excess of 1 year. An increasingly adopted pathway is that of mainstreaming, whereby genetic testing is managed locally by a multidisciplinary team member. Our institution therefore implemented an Advanced Nurse Practitioner (ANP)-led service with responsibility for the LS Diagnostic Pathway and mainstream genetic testing. Data was extracted from a prospectively maintained database of all newly diagnosed CRC patients discussed at our institutions CRC multidisciplinary meeting (MDM) between January 1st, 2023, and May 31st, 2024. MMR IHC testing was performed in 97.9% of the 385 patients diagnosed with CRC. The median time from histological confirmation of CRC to the availability of the MMR IHC report was 6 days. All 51 patients (100%) who required sequential tumor testing underwent BRAF V600 ± MLH1 promoter methylation testing. Additionally, 100% of the 14 patients eligible for mainstream genetic testing were referred to the ANP-led genetics service. The median time from the initial MDM discussion to the initiation of genetic testing was 69 days, while the median time from testing to the availability of results was 19 days. Patients received their results within a median of 21 days. MMR IHC testing increases the detection of LS through identification of dMMR tumours. Successful downstream delivery of clinical services, however, requires appropriate subsequent management, in a resource-limited environment. Our institutional experience demonstrates the feasibility, efficiency, and effectiveness of an ANP-led mainstreaming model of care for hereditary colorectal cancer.

Precocious Puberty in Boys with NR0B1 Variants

Precocious puberty (PP) requires appropriate management to prevent short adult height, psychosocial issues, and other adverse outcomes. Genetic diagnosis potentially improves the management of PP. Pathogenic NR0B1 variants, which typically cause X-linked adrenal hypoplasia congenita, can also affect gonadal function. While boys with NR0B1 variants usually exhibit hypogonadotropic hypogonadism during adolescence, previous reports have suggested that minipuberty, a physiological transient activation of the hypothalamic–pituitary–gonadal axis during infancy, occurs in these patients and can persist beyond a typical duration. In rare cases, NR0B1 variants cause PP. PP associated with NR0B1 variants has unique features such as early onset and high serum testosterone levels that are often disproportionate to testicular size. Three underlying mechanisms have been proposed for the association between PP and NR0B1 variants: (1) adrenocorticotropic hormone (ACTH)-dependent, (2) gonadotropin-dependent, and (3) ACTH- and gonadotropin-independent mechanisms. The factors contributing to PP vary among cases. Determining the underlying mechanisms is crucial for adopting appropriate therapeutic strategies to control PP. However, as the detailed molecular networks mediating these mechanisms are largely unclear, further research is needed to pave the way for a more effective and personalized management of patients with PP associated with NR0B1 variants.

Non-infectious mixed cryoglobulinemia as a new clinical presentation of mutation in the gene encoding coatomer subunit alpha: a case report of two adult sisters

Cryoglobulinemia is a rare disease characterized by the presence of cryoglobulins in the blood serum. It is usually caused by autoimmune, lymphoproliferative, or infectious factors. The pathogenesis of cryoglobulinemia is not well understood, therefore, genetic testing is very important. We present the case of two adult sisters with different clinical phenotypes of non-infectious cryoglobulinemic vasculitis associated with a rare genetic variant [(Hg38) 1:160323529 C&amp;gt;G, NP_004362.2:p.(Gly203Ala)]. One of the sisters suffered from essential mixed cryoglobulinemia, while the other suffered from cryoglobulinemia associated with systemic connective tissue disease. In both cases, genetic tests revealed a variant in the COPA gene, encoding coatomer subunit alpha. Mutations in the COPA gene are associated with COPA syndrome, an autoimmune interstitial lung, joint, and kidney monogenic disease, found mainly in children. Only 15 pathogenic COPA variants have been reported thus far which suggests that the full spectrum of disease manifestations remains unknown. Ours is the first report of the association of the COPA gene with non-infectious cryoglobulinemic vasculitis in adults. This unexpected finding may direct research into the pathogenesis of cryoglobulinemia and new treatment strategies for this rare disease.

A case series of three patients with extensive lung metastatic pheochromocytoma/paraganglioma: evaluation, treatment challenges, and outcomes

Pheochromocytomas (PCCs) and paragangliomas (PGLs; together PPGLs) are uncommon neuroendocrine tumors arising from adrenal medullary chromaffin cells and sympathetic/parasympathetic paraganglia. Though PPGLs predominate in adult populations, pediatric cases of PPGLs represent more aggressive disease outcomes with 12% being diagnosed as metastatic. Metastatic disease (spread to bone, lung, lymph nodes, or liver) occurs in a subset of PPGLs, ranging from 15% to 17% depending on the underlying pathogenic variant. Historically, pulmonary metastases present clinically as multiple small lesions; however, cases of PPGLs with innumerable small metastases (a miliary pattern) overwhelming lung parenchyma define a novel yet exceptionally challenging disease presentation. This pattern of pulmonary lesions upon treatment and/or cellular lysis may lead to both respiratory decompensation as well as prolific catecholamine release, incurring significant morbidity and mortality if not appropriately managed. Of the 2,649 PPGL patients enrolled in our protocol from January 1, 2000, to April 30, 2023, 500 had metastatic disease, 122 were children/adolescents, and 3 of the 122 children/adolescents had extensive pulmonary metastatic disease. All three adolescent patients with extensive pulmonary metastases had cluster 1 PPGLs and suffered hypoxemia (due to pulmonary metastases) leading to overactive hypoxia signaling and catecholamine-induced signs and symptoms [among them hypertension and/or tachyarrhythmia(s)]. Interventions including surgery, chemotherapy, and radiotherapy were pursued. Two patients achieved disease stability, while one patient succumbed to disease. Ultimately these divergent outcomes emphasize the importance of recognizing poor prognostic factors and aggressive disease early, to select appropriate treatments. Thus, optimal management of these patients must consider complications of catecholamine excess and the profound influence of hypoxia. Herein, we describe three adolescent cases of extensive pulmonary metastatic PPGL and the unique clinical challenges faced in treating these tumors alongside relevant literature to provide guidance on appropriate interventions (ClinicalTrials.gov identifier: NCT00004847).

Insights From a Novel Splicing Variant and Recurrent Arginine Variants in the CHD3 Gene Causing Snijders Blok-Campeau Syndrome.

Snijders Blok-Campeau syndrome (SNIBCPS, OMIM#618205) is an autosomal dominant neurodevelopmental disorder attributed to pathogenic variants in the chromodomain helicase DNA binding protein 3 (CHD3) gene. To date, more than 100 individuals have been diagnosed with SNIBCPS. The syndrome is characterized by intellectual disability, global developmental delay, speech or language impediments, and dysmorphic features associated with macrocephaly. Additionally, affected individuals may exhibit behavioral issues, hypotonia, and autistic traits. A novel splicing variant (c.5590+1G > T) in the C-terminal 2 region of the CHD3 gene was identified in a patient predominantly exhibiting autistic characteristics. Invitro minigene splicing experiments conducted in HEK293 cells revealed that aberrant splicing resulted in the formation of a cryptic site 46 nucleotides downstream of the 5' splice site. This alteration was predicted to disrupt the reading frame by eliminating the physiological stop codon, consequently causing an extension in protein translation. Furthermore, an additional patient presenting with hypotonia, dysmorphic features, and global developmental delay was documented. This patient harbored a missense variant in the helicase C-terminal domain, c.3505C > T (p. Arg1169Trp). The pathogenic variant was anticipated to impact chromatin remodeling capacity and enzyme activity. Given the high prevalence of arginine residue pathogenic variants in the CHD3 protein and its notable propensity for binding and storing ATP molecules, intriguing insights into the potential effects of arginine residue pathogenic variants on phenotypes are provided. These findings contribute to a more comprehensive understanding of the genetic landscape of SNIBCPS while elucidating potential molecular mechanisms underlying the syndrome.

Sensory-Motor Polyneuropathy in an 11-year- old Girl with a Pathogenic Variant in SMC1A: A Case Report.

Pathogenic variants in the SMC1A gene are often dominant-negative and cause an X-linked form of Cornelia de Lange syndrome (CdLS) with growth retardation and typical facial features. However, rare SMC1A variants cause a developmental and epileptic encephalopathy (DEE) with intractable early-onset epilepsy that is absent in CdLS. Here we describe an 11-year-old girl with epilepsy, walking disorder, and neurodevelopmental disorder. A neurophysiological examination of nerve conduction velocity showed a mixed, sensory-motor, chronic 4-limb polyneuropathy. Whole-exome sequencing identified the variant c.3145C > T p.(Arg1049*) in SMC1A (NM_006306.3), which can be classified as pathogenic. To the best of our knowledge, among 79 individuals with SMC1A-related DEE reported in the literature, altered peripheral nerve conduction has never been described. In this article, we propose that severe sensory-motor polyneuropathy could be an expansion of the SMC1A-related phenotype.

Individuals with SATB2-associated syndrome have impaired vitamin and energy metabolism pathways.

Special AT-rich sequence-binding protein 2 (SATB2) is a master regulator of gene expression. Mutations of the SATB2 gene results in the SATB2-associated syndrome (SAS), a genetic disorder characterized by neurodevelopmental disabilities and autism-related phenotype. The importance of plasma as an indicator of SAS phenotypes is unknown. We aim to investigate if pathogenic variants in SATB2 are associated with alteration to relevant pathways in the plasma of SAS patients and identify key differentially regulated proteins which may serve as biomarkers to improve diagnostic and future pharmacological approaches. We used well-validated proteomic technologies to determine the proteomic profile of plasma from SAS patients compared to healthy control subjects. Bioinformatical analysis was performed to identify significant proteins and functionally enriched pathways. We identified differentially expressed proteins in the plasma of SAS patients that are significantly involved in metabolism-related pathways. Energy metabolism, glucose metabolism and vitamin metabolism pathways are significantly enriched in SAS patients as compared to healthy controls. Our study linked SATB2 mutations to the impairment of plasma proteins involved in different metabolic pathways in SAS patients.