Limb Malformations Research Articles

Clinical phenotype and genetic analysis of a child with partial duplication of 10q and a literature review

To explore the clinical phenotype and pathogenesis of a child with partial duplication in the long arm of chromosome 10 (10q), and conduct a review of relevant literature. A child presented at Lianyungang Maternal and Child Health Care Hospital in April 2018 for growth retardation, intellectual disability, and autism spectrum disorder (ASD) was selected as the study subject. Peripheral blood samples were collected from the child and his parents for G-banded chromosomal karyotyping analysis. Genomic DNA was also extracted for chromosomal microarray analysis (CMA). The clinical phenotype and relevant genes were searched in the Online Mendelian Inheritance in Man (OMIM) and the UK Database of Genomic Variation and Phenotype in Humans using Ensembl Resources (DECIPHER). The pathogenicity of chromosomal variation was analyzed based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Relevant literature was searched from the CNKI, Wanfang Data, and PubMed databases by using keywords such as "10q" "duplication" and "trisomy", with the time set as from the establishment of database to December 1, 2023. This study has been approved by the Medical Ethics Committee of the Lianyungang Maternal and Child Health Care Hospital (No. XM2023030). The clinical phenotype of child had included growth retardation, intellectual disability, and ASD. G-banded chromosomal analysis suggested that the child has a karyotype of 46,XY,dup(10)(q23.31q24.33), whilst both of his parents were normal. CMA analysis of the child revealed that the child was arr[19]10q23.31q24.33(87603382_104948862)×3, with a 17.34 Mb duplication in the 10q23.31q24.33 region. Search of the OMIM database suggested that the duplicated segment has contained 171 genes associated with various diseases, and search of the DECIPHER database has identified cases with overlapping with the duplication. A search of the PubMed database has identified 2 publications involving 2 patients with chromosomal duplications overlapping the 10q23.31q24.33 region with a segment length of > 10 Mb. The 2 patients had mainly manifested growth retardation, intellectual disability, ASD, and facial and limb malformations. The main pathogenic genes had included PTEN, WNT8B, LZTS2, NFKB2, PAX2, KIF11, FRA10AC1, and CNNM2. No similar case was retrieved from the CNKI and Wanfang Data databases. The partial 10q duplication as a novel CNV involving genes such as PTEN and WNT8B probably underlay the growth retardation, intellectual disability and ASD in child 1 . This study has enriched the genotype-phenotype spectrum of patients with partial 10q23.31q24.33 duplications.

Rare Combination of Congenital Microtia and Limb Malformations: Analysis of Etiology and Treatment.

Congenital microtia is the second most common congenital craniofacial deformity, and limb malformation is the most common birth defect. The combination of the 2 deformities is rare. In this study, the authors present 3 cases with a rare combination of congenital microtia and limb malformations and analyze the etiology and treatment of the malformations. There may be genetic homology between these two malformations, and they can be associated with abnormal ectodermal migration. Level IV-case study.

Genetic analysis of preaxial polydactyly: identification of novel variants and the role of ZRS duplications in a Chinese cohort of 102 cases.

Preaxial polydactyly (PPD) is a congenital limb malformation, previously reported to be caused primarily by variants in the ZRS and upstream preZRS regions. This study investigated genetic variations associated with PPD, focusing on point variants and copy number variations (CNVs) in the ZRS and preZRS regions. Comprehensive genetic analyses were conducted on 102 patients with PPD, including detailed clinical examinations and Sanger sequencing of the ZRS and preZRS regions. Additionally, real-time quantitative PCR (qPCR) was used to detect CNVs in the ZRS region. The evolutionary conservation and population frequencies of identified variants were also evaluated. Six point variants were identified, among which four are likely pathogenic novel variants: 93G > T (g.156584477G > T), 106G > A (g.156584464G > A), 278G > A (g.156584292G > A), and 409A > C (g.156585378A > C). Additionally, qPCR analysis revealed that 66.67% of patients exhibited ZRS duplications. Notably, these duplications were also present in cases with newly identified potential pathogenic point variants. These findings suggest the possible interaction of point variants in ZRS and preZRS through a common pathogenic mechanism, leading jointly to PPD. The findings expand the variant spectrum associated with non-syndromic polydactyly and highlight that, despite different classifications, anterior polydactyly caused by variants in ZRS and nearby regions may share common pathogenic mechanisms. The incorporation of various variant types in genetic screening can effectively enhance the rate of pathogenic variant detection and contribute to the cost-effectiveness of genetic testing for limb developmental defects, thereby promoting healthy births.

Comparison of Galaxy and Unix tools for analyzing the exome sequencing data from syndactyly abnormalities

Syndactyly is a congenital limb abnormality, which manifests as the fusion of digits due to incomplete separation during embryonic development, and its pathogenesis involves intricate genetic and molecular processes. Since Exome sequencing has gained widespread utilization as an invaluable tool for exploring genetic disorders during prenatal development, the Bioinformatic platforms, such as GALAXY and UNIX, play a central role in the analysis process of exome sequencing data, facilitating precise identification and interpretation of genetic variations linked to congenital abnormalities. In this study, we conducted a comparative analysis of exome sequencing data from a 1.5-year-old syndactyly patient using two platforms: GALAXY and UNIX. The UNIX platform identified a total of 275,572 variants, and the GALAXY platform identified 140,291 variants when compared with the Grch38/hg38 reference genome. A comparative analysis identified 126,848 common variants between the platforms. After filtration with the 200 syndactyly-related genes, 1,345 variants were remained. The distribution of these 1,345 variants spans the entirety of the patient's genome, with focal concentrations observed on specific chromosomes including chromosomes 2, 4, and 11. Concurrently, within the top 200 genes implicated in syndactyly, the genes FRAS1, CACNA1C, GLI2, and NOTCH1 exhibit the highest frequency of variants. These data emphasized the impact of the chosen analytical platform on genetic variation detection in congenital limb abnormalities, provided critical insights into the selection of bioinformatic tools for optimizing exome sequencing workflows in the context of limb malformations, contributed to advancements in genetic research and diagnostic methodologies.

9342 Managing Osteoporosis In Patients With Phocomelia: Challenges And Strategies

Abstract Disclosure: M. Renzu: None. C. Hubers: None. V. Mehta: None. A.M. Qazi: None. A.M. Satei: None. D.K. Yerasuri: None. Introduction: Phocomelia, a rare congenital limb malformation, often results from disruptions in limb bud formation during embryonic stage, due to genetic mutations, teratogens, or environmental factors like thalidomide embryopathy. These disruptions pose unique challenges in bone health management, including an increased risk of osteoporosis.We present a case report of a 52-year-old patient with phocomelia who developed an early onset severe osteoporosis. This case stresses the need for specific measures and care to tackle bone health in individuals with congenital limb anomalies. Case Presentation: A 52-year-old white female with phocomelia, had absence of the left forearm and hand, as well as a transverse tibial deficiency with a prosthetic left lower leg since the age of 1. Osteoporosis was diagnosed after follow-up, with initial osteopenia noted at age 49. DEXA scan showed lumbar osteopenia, radial osteoporosis, and bilateral femoral neck osteopenia. FRAX score showed an 11.9% risk of osteoporotic fracture and 3.1% risk of a hip fracture.Risk factors to her osteoporosis included late menarche, early menopause due to hysterectomy, and a history of hormone replacement therapy without pregnancies. Also, chronic colitis and diarrhea caused malabsorption issues. Her left hip bone mineral density was disproportionately low due to chronic prosthesis use, necessitating close monitoring and treatment initiation with Denosumab, along with vitamin D3 and calcium supplementation.As of the latest follow-up, the patient is closely monitored, and improvement is noted in her condition. She has incorporated daily gym sessions into her routine, indicating proactive engagement in her well-being. Discussion: Managing osteoporosis in patients with phocomelia needs a personalized approach, considering the patient's unique anatomical challenges and the limitations of traditional osteoporosis management strategies. Bone tissue adapts its structure based on mechanical loading, with reduced loading in deformed limbs leading to increased resorption and elevated osteoporosis risk. Tailored treatment plans, including Denosumab, which is known as an effective pharmacological option for managing osteoporosis, complemented by dietary adjustments to enhance vitamin D and calcium intake. Physical therapy programs play a vital role in muscle strengthening and balance improvement, reducing fracture risk.Another challenge that patients with phocomelia face is barriers to accessing healthcare services, like limited specialized care providers, financial constraints, and transportation difficulties, leading to increased morbidity. Hence early screening and intervention are essential to prevent osteoporotic complications. Overall, a comprehensive approach to osteoporosis management in phocomelia patients is crucial for optimizing outcomes and enhancing quality of life. Presentation: 6/3/2024

The overlapping of phenotypes in Wiedemann-Steiner, Kleefstra and Coffin-Siris syndromes: a study of eleven patients

BackgroundSome chromatinopathies may present with common clinical findings (intellectual disability, brain and limb malformation, facial dysmorphism). Furthermore, one of their cardinal shared features is growth dysregulation.We aimed to assess and deepen this resemblance in three specific conditions, namely Wiedemann-Steiner (WDSTS), Kleefstra (KLEFS1) and Coffin-Siris syndrome (CSS1), with a particular focus on possible metabolic roots.Methods Eleven patients were enrolled, three with WDSTS, five with KLEFS1 and three with CSS1, referring to Fondazione IRCCS Ca’ Granda Ospedale Maggiore, Milan, Italy. We performed both a physical examination with detailed anthropometric measurements and an evaluation of the patients’ REE (rest energy expenditure) by indirect calorimetry, comparing the results with age- and sex-matched healthy controls.ResultsWe observed new clinical features and overlap between these conditions suggesting that different disturbances of epigenetic machinery genes can converge on a common effect, leading to overlapping clinical phenotypes. The REE was not distinguishable between the three conditions and healthy controls.ConclusionsEpigenetic machinery plays an essential role both in growth regulation and in neurodevelopment; we recommend evaluating skeletal [craniovertebral junction abnormalities (CVJ) polydactyly], otolaryngological [obstructive sleep apnea syndrome (OSAs), recurrent otitis media], dental [tooth agenesis, talon cusps], and central nervous system (CNS) [olfactory bulbs and cerebellum anomalies] features. These features could be included in monitoring guidelines. Further studies are needed to deepen the knowledge about energy metabolism.

Fgf8 contributes to the pathogenesis of Nager syndrome

Nager syndrome (NS, OMIM 154400) is a rare disease characterized by craniofacial and limb malformations due to variants in the gene encoding splicing factor 3B subunit 4 (SF3B4). Although various noncanonical functions of SF3B4 unrelated to splicing have been previously described, limited studies elucidate molecular mechanisms underlying NS pathogenesis. Here we showed that sf3b4-deficient fish displayed craniofacial and segmentation defects associated with suppression of fgf8 levels, which perturbed FGF signaling and neural crest cell (NCC) expression. Our finding also pointed out that oxidative stress-induced apoptosis was prominently detected in sf3b4-deficient fish and may further exaggerate the bone remodeling process. Notably, injection of exogenous FGF8 significantly rescued the demonstrated defects in sf3b4-deficient fish, which further supported the participation of Fgf8 in NS pathogenesis. Overall, our study provides valuable insights into the molecular mechanism underlying developmental abnormalities observed in NS and suggests future therapeutic strategies to protect against the pathogenesis of NS and possibilities for preventing severe outcomes.

Phenotypes, Genetics, and Estimated Prevalence of Focal Dermal Hypoplasia (Goltz Syndrome): A Single-Center Report.

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is a rare ectodermal dysplasia that primarily affects the skin, skeleton, and eyes. It is an X-linked dominant disorder, predominantly seen in females, caused by pathogenic variants in PORCN. We characterized a case series of four genetically confirmed FDH patients (three females, one male) at Aarhus University Hospital, Denmark. We estimated the FDH prevalence from our local cohort and nationwide registry data. Three patients had characteristic dermatological findings suspicious for FDH and confirmed by targeted PORCN analysis. One patient had an atypical presentation with several malformations but only subtle skin changes and was diagnosed following trio exome-sequencing analysis. Skin atrophy with fat herniations and telangiectasias were typical cutaneous findings. Limb malformations included oligodactyly (cleft foot), syndactyly, and polydactyly. Eye abnormalities included coloboma and microphthalmos. Facial dysmorphology was defined by asymmetry, thin upper lip, and malformed ears. One patient developed a giant cell bone tumor, which is a rare feature of FDH. Dental findings included enamel hypoplasia with vertical grooving and irregular crowns. Four PORCN variants were identified, including three not previously reported in the literature.We estimated a regional point prevalence in Western Denmark of 1.6 cases per million population (95% confidence intervals (CI): 0.7-3.7 per million) and a nationwide registry-based point prevalence of 1.2 cases per million population (95% CI: 0.6-2.4 per million). FDH is an extremely rare and complex multisystem disorder of variable presentation, which requires close multidisciplinary collaboration for diagnosis and patient care.

Examination of piperonyl butoxide developmental toxicity as a Sonic hedgehog pathway inhibitor targeting limb and palate morphogenesis

Piperonyl butoxide (PBO) is a pesticide synergist with widespread use and human exposure that was discovered to inhibit Sonic hedgehog (Shh) signaling, a pathway required for numerous developmental processes. Previous examinations of PBO’s potential for developmental toxicity have generated seemingly conflicting results. We investigated the impact of acute PBO exposure targeting Shh pathway activity during palate and limb morphogenesis. Timed-pregnant C57BL/6 J mice were exposed to a single PBO dose (67–1800 mg/kg) at gestational day (GD) 9.75, and litters were collected at GD10.25 and GD10.75 to examine Shh pathway activity or GD17 for phenotypic assessment. PBO exposure induced dose-dependent limb malformations and cleft palate in the highest dose group. Following PBO exposure, reduced expression of the Shh pathway activity markers Gli1 and Ptch1 was observed in the embryonic limb buds and craniofacial processes. These findings provide additional evidence that prenatal PBO exposure targeting Shh pathway activity can result in malformations in mice that parallel common etiologically complex human birth defects.

Multiple congenital anomalies in two fetuses with glutathione-synthetase deficit (GSS).

Glutathione synthetase deficiency is a rare inborn metabolic disease usually caused by biallelic variants in GSS. Clinical severity varies from isolated hemolytic anemia, sometimes associated with chronic metabolic acidosis and 5-oxoprolinuria, to severe neurological phenotypes with neonatal lethality. Here we report on two fetal siblings from two pregnancies with glutathione synthetase deficiency exhibiting similar multiple congenital anomalies associating phocomelia, cleft palate, intra-uterine growth retardation, genito-urinary malformations, and congenital heart defect. Genome sequencing showed that both fetuses were compound heterozygous for two GSS variants: the previously reported pathogenic missense substitution NM_000178.4 c.800G>A p.(Arg267Gln), and a 2.4 kb intragenic deletion NC_000020.11:g.34944530_34946833del. RNA-seq on brain tissue revealed the out-of-frame deletion of the exon 3 and an almost monoallelic expression of the missense variant (88%), suggesting degradation of the deletion-harboring allele by nonsense-mediated mRNA decay. 5-oxoproline (pyroglutamic acid) levels in amniotic fluid were elevated, suggesting an alteration of the gamma-glutamyl cycle, and corroborating the pathogenicity of the two GSS variants. Only one case of glutathione synthetase deficiency with limb malformations has previously been reported, in a newborn homozygous for the c.800G>A variant. Thus, our data allow us to discuss a potential phenotypic extension of glutathione synthetase deficiency, with a possible involvement of the c.800G>A variant.

Identification of a pathogenic variant and pre-implantation genetic testing for a Chinese family affected with split-hand/foot malformation.

Split-hand/foot malformation is a serious congenital limb malformation characterized by syndactyly and underdevelopment of the phalanges and metatarsals. In this study, we reported a case of a fetus with hand-foot cleft deformity. Whole exome and Sanger sequencing were used to filter out candidate gene mutation sites and provide pre-implantation genetic testing(PGT) for family members. Genetic testing results showed that there was a homozygous mutation c.786G>A (p.Trp262*) in the fetal WNT10B, and both parents were carriers of heterozygous mutations. PGT results showed that out of the two blastocysts, one was a heterozygous mutant and the other was a homozygous mutant. All the embryos had diploid chromosomes. The heterozygous embryo was transferred, and a singleton pregnancy was successfully achieved. This study suggests that homozygous mutations in WNT10B are the likely cause of hand-foot clefts in this family. For families with monogenic diseases, preimplantation genetic testing can effectively prevent the birth of an affected child only after identifying the pathogenic mutation.

Hypohidrotic ectodermal dysplasia in a family: expanding spectrum of LEF-1 related disorders.

We report a novel heterozygous loss-of-function LEF1 variant in a 3-year-old girl and her mother, both diagnosed with hypohidrotic ectodermal dysplasia. The patients presented with sparse hair, dry skin, and oligodontia but lacked limb or mammary malformations, expanding the clinical spectrum of LEF1-related disorders. The study provides new insights into the variability and management of ectodermal dysplasias related to LEF1 gene.

Phenotypic and genotypic analysis of 11 fetal cases with Bardet-Biedl syndrome.

To present the prenatal sonographic features and genomic spectrum of pregnancies with fetal Bardet-Biedl syndrome (BBS). This was a retrospective study of 11 cases with BBS diagnosed by prenatal ultrasound and confirmed by genetic testing. Clinical and laboratory data were collected and reviewed for these cases, including maternal demographics, prenatal sonographic findings, molecular testing sequencing results, and pregnancy outcomes. All cases had unremarkable first-trimester ultrasound scans without reporting limb malformations. All had second-trimester abnormal ultrasounds: postaxial polydactyly in nine cases (9/11), renal abnormalities in seven (7/11), reduced amniotic fluid volume in two (2/11), central nervous system anomalies in two (2/11), and ascites in three (3/11). Ten fetuses presented with at least two-system anomalies, and one (Case 11) presented with only postaxial polydactyly. Variants were detected in five genes, including BBS2, ARL6/BBS3, BBS7, CEP290/BBS14 and IFT74/BBS22. Ten pregnancies were terminated in the second trimester, while one continued to term. Enlarged hyperechogenic kidneys and postaxial polydactyly are the two most common sonographic features of fetal BBS. Prenatal diagnosis of BBS can be done with ultrasound and genetic testing although the diagnosis may be made in the second trimester.

Congenital Anomalies in American Crocodile (Crocodylus acutus, Cuvier, 1807) Embryos from a Farm Breeder in Colombia.

The American crocodile (Crocodylus acutus, Cuvier, 1807) (Class Reptilia, Family Crocodylidae) is a crocodile species inhabiting the Neotropics. Congenital defects have been described in almost every vertebrate group. In crocodiles, teratology alterations have been described in captive animals (pets, zoos, farms) such as Crocodylus niloticus or Gavialis gangeticus. The present study aimed to characterize congenital malformations of C. acutus from a farm in Lomas de Matunilla, Ballestas, Bolívar, Colombia. A total of 550 unhatched eggs were examined after embryo death. A total of 61 embryos presented malformations, with 42 different types of anomalies observed. Limb and tail malformations (29%) were the most common malformations observed. Several malformations, such as cephalothoracopagus, thoracopagus, sternopagus, xiphopagus twins, campylorrachis scoliosa, and acrania, were documented in crocodiles for the first time. Research in teratology enhances our understanding of crocodile biology. It plays a role in their conservation and management, thus helping to ensure the long-term viability of these species in their natural habitats.

PARAMETERS OF THE INTERCONDYLAR FOSSA OF THE FEMUR IN CHILDRENIN NORMAL CONDITIONS AND WITH CONGENITAL MALFORMATIONS OF THE LOWER LIMBS

According to literature sources, radiography can indirectly visualize congenital insufficiency of the cruciate ligaments both in isolated form and in combination with other congenital malformations of the lower extremities. Objective. To study the parameters of the intercondylar fossa of the femur in children of different age groups with stable/unstable knee jo ints due to congenital malformations of the lower limbs using instrumental imaging methods. Methods. A prospective diagnostic study was conducted of 359 knee joints of 217 children who were treated at the pediatric orthopedics clinic from 2019to 2022 and with a retrospective control group (2010–2021). limbs, as well as with congenital malformations of the lower limbs. X-ray examinations were performed on the OPERA T90cex X-ray and fluoroscopic system. Results. 217 patients took part in the study, including 105 patients without knee jointpathology and 112 with congenital malformations of the lower limbs. Comparison of the accuracy of radiological diagnostic indicators was performed using the Studentʼs t-test with the results of computer and magnetic resonance imaging studies, which showed the absence of a statistically significant differencein the results research. A diagnostic study was also conducted to find the regularity of the development of the knee joints and to identify the parameters of the radiological norm of the development of the intercondylar fossa of the femur in children of different age categories. Conclusions. Using the resultsof instrumental studies, the parameters of the intercondylar fossa of the femur in children of different age categories with stable and unstable knee joints due to congenital malformations of the lower limbs were investigated. The results of the study should be taken into account for the diagnosis of congenital defects of the knee joint.

Concomitant use of antidepressants and benzodiazepines during pregnancy and associated risk of congenital malformations: a population-based cohort study in Taiwan

Despite the frequent co-administration of antidepressants and benzodiazepines, the association between such concomitant use during pregnancy and the risk of congenital malformations remains inadequately explored. This study aims to examine the association between concomitant use of antidepressants and benzodiazepines during the first trimester and organ-specific congenital malformations. We conducted a population-based cohort study using Taiwan's National Birth Certificate Application database, the Maternal and Child Health database, and Taiwan's National Health Insurance database. Pregnant people aged 15-50 years with singleton births between Jan 1, 2004, and Dec 31, 2018, were included. Use of antidepressants and benzodiazepines was defined as at least one prescription during the first trimester, and concomitant use was defined as the overlapping prescription of both drugs with an overlapping prescription period. The primary outcomes were overall congenital malformations and eight organ-specific malformations, consisting of the nervous system, heart, respiratory system, oral cleft, digestive system, urinary system, genital system, and limb malformations. Logistic regression models with propensity score fine stratification weighting approach were used to control for measured confounders. Analyses controlling for confounding by indication and sibling comparison analyses were done to address unmeasured confounders. No individuals with lived experience participated in the research or writing process. The cohort included 2 634 021 singleton pregnancies, and 8599 (0·3%) individuals were concomitant users of antidepressants and benzodiazepines during the first trimester (mean age at delivery was 31·8 years [SD 5·2] for pregnancies with exposure to antidepressants and benzodiazepines vs 30·7 years [SD 4·9] for pregnancies without exposure). All study participants were female, and information about ethnicity was not available. Absolute risk of overall malformations was 3·81 per 100 pregnancies with exposure, compared with 2·87 per 100 pregnancies without exposure. The propensity score-weighted odds ratios (weighted ORs) did not suggest an increased risk for overall malformations (weighted OR 1·10, 95% CI 0·94-1·28), heart defects (1·01, 0·83-1·23), or any of the other organ-specific malformations, except for digestive system malformations, for which the weighted OR remained statistically significant after adjustment (1·63, 1·06-2·51). The absence of an increased risk for overall congenital malformations associated with concomitant use of antidepressants and benzodiazepines was supported by the analyses controlling for confounding by indication and sibling-matched comparisons. The findings of this study suggest that the concomitant use of antidepressants and benzodiazepines during the first trimester is not associated with a substantial increase in risk for most malformation subtypes. However, considering other potential adverse effects of using both medications concomitantly, a thorough assessment of the risks and benefits is crucial for clinical decision making. National Science and Technology Council.

A Novel Variant in the Cyto-Tail of SMO Gene Underlying Isolated Postaxial Polydactyly

Background: Polydactyly is one of the most common hereditary limb malformations, characterized by presence of additional digits in hands and/or feet. It is present either in isolated form or in combination with other features. Preaxial polydactyly with extra digit on the outside of the thumb or big toe, and postaxial polydactyly with extra digit on the outside of the little finger or little toe are the two main forms of polydactyly. Methods and Results: In the present study, two unrelated consanguineous families segregating PAP in an autosomal recessive manner were investigated. Whole exome sequencing, followed by segregation analysis using Sanger sequencing, revealed a homozygous missense variant [c.1792 G>A; p.(Gly598Arg); NM_005631.5] in the SMO in both families. Proteins SMO, PTCH, and GLI act as major components of the Sonic hedgehog pathway, which transmits signals to embryonic cells for cellular differentiation. Homology modeling revealed that the variant in SMO may disrupt proper protein folding and interaction with other molecules. Conclusion: Our study has revealed the second direct involvement of a sequence variant in the SMO causing isolated polydactyly. This study will highlight the importance of the inclusion of the SMO gene in screening individuals presenting polydactyly in hands and feet.

Skeletal malformation in growing milk sheep.

Two six-month old female Lacaune lambs with severe skeletal malformations of both front limbs were presented to the Department of Farm Animals, University of Zurich. The clinical examination showed alert animals with a high body weight and body condition score as well as a valgus deformation without pain or swelling. Radiographic examination showed severe irregularities in the epiphysial plate of the metacarpal bones in both lambs. Delayed growth in the lateral aspects of the physis was evident and resulted in valgus deformation. Nutritional causes were considered as the main reason for this presentation and a nutritional consultation was performed by the Institute of Animal Nutrition and Dietetics, University of Zurich. The estimated energy intake of these lambs was 65 % higher than the recommended maximum for growing sheep and the estimated vitamin D content of the diet was 71 % below the recommended allowance. Both animals were euthanized, and peripheral quantitative computed tomography (pQCT) was performed postmortem to measure total bone mineral density (BMD), trabecular bone mineral density (tBMD) and cortical bone mineral density (cBMD) of the left and right metatarsal bone of both animals. The BMD and the tBMD at 10 % of bone length were below the reference values and the BMD at 50 % was above the reference values. In addition, postmortem examination revealed a Salter-Harris-Typ-1 facture in the right caput humeri of one lamb. Histological evaluation showed defects in the articular cartilage with an eburnation in the metacarpal region and a disrupted area of columnar cartilage. This case report supports the fact that a high dietary energy intake leads to damage to the cartilage and the epiphyseal zone in sheep. In addition, insufficient dietary vitamin D intake contributed to the incomplete bone mineralization, as well as delayed growth and skeletal malformation.

Case Report of Recurrent Popliteal Pterygium Syndrome

AbstractA 23 week pregnant woman with a history of a child with facial and limb malformations underwent a fetal ultrasound revealing similar abnormalities in the current fetus. Genetic testing confirmed a new IRF6 gene mutation consistent with popliteal pterygium syndrome type 1. This case highlights the potential for recurrence and the role of genetic testing in prenatal diagnosis.

Prenatal phenotype and genetic analysis of a fetus with Fibrochondrogenesis 1 due to compound heterozygous variants of COL11A1 gene

To explore the genetic etiology of a fetus with short limbs identified by prenatal ultrasonography. A fetus detected with short limb malformations at Shengjing Hospital Affiliated to China Medical University on October 25, 2021 was selected as the study subject. Prenatal ultrasound and post-abortion imaging were carried out to determine the phenotypic characteristics of the fetus. Amniotic fluid sample of the fetus and peripheral blood samples of its parents were collected. Following extraction of genomic DNA, whole-exome sequencing was carried out. Candidate variants were verified by Sanger sequencing. Online software was used to predict the structural changes of the mutant proteins. Prenatal ultrasound showed that the fetus had a small bell-shaped thorax, markedly shortened limbs, flat midface, a small nose with anteriorly tilted nostrils, and a small mandible. Post-abortion CT showed typical short and wide fetal ribs, cupped metaphyses at both ends, short long bones with wide metaphyses, resulting in a dumbbell-shaped appearance and curved thoracic vertebrae. Whole-exome sequencing revealed that the fetus had harbored compound heterozygous variants of the COL11A1 gene, namely c.2251G>T and c.3790G>T, both of which were predicted to alter the important Gly-X-Y structure of collagen protein. Sanger sequencing confirmed that the variants were respectively inherited from its parents. A rare fetus with Fibrochondrogenesis type 1 due to compound heterozygous variants of the COL11A1 gene has been diagnosed. Above finding has enabled genetic counseling and reproductive guidance for this family.