A Frameshift Variant in KIAA0825 Causes Postaxial Polydactyly.
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ABSTRACT:
SUBMITTER: Bilal M
PROVIDER: S-EPMC7983616 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Postaxial polydactyly (PAP) is a common limb malformation that often leads to cosmetic and functional complications. Molecular evaluation of polydactyly can serve as a tool to elucidate genetic and signaling pathways that regulate limb development, specifically, the anterior-posterior specification of the limb. To date, only five genes have been identified for nonsyndromic PAP: FAM92A, GLI1, GLI3, IQCE and ZNF141. In this study, two Pakistani multiplex consanguineous families with autosomal recessive nonsyndromic PAP were clinically and molecularly evaluated. From both pedigrees, a DNA sample from an affected member underwent exome sequencing. In each family, we identified a segregating frameshift (c.591dupA [p.(Q198Tfs*21)]) and nonsense variant (c.2173A?>?T [p.(K725*)]) in KIAA0825 (also known as C5orf36). Although KIAA0825 encodes a protein of unknown function, it has been demonstrated that its murine ortholog is expressed during limb development. Our data contribute to the establishment of a catalog of genes important in limb patterning, which can aid in diagnosis and obtaining a better understanding of the biology of polydactyly.
| S-EPMC6724712 | biostudies-literature
Project description:BackgroundPostaxial polydactyly (PAP) is one of the commonest congenital malformations and usually is associated to several syndromes. There is no primary investigational strategy for PAP cases with single gene disorder in literature. PAP cases with single gene disorder can be classified according to common pathways and molecular basis. Molecular classification may help in diagnostic approach.Materials and methodsAll single gene disorders associated with PAP reported on PubMed and OMIM are analyzed and classified according to molecular basis.ResultsMajority of genes related to cilia structure and functions are associated with PAP, so we classified them as ciliopathies and non-ciliopathies groups. Genes related to Shh-Gli3 pathway was the commonest group in non-ciliopathies.ConclusionGenes related to cilia are most commonly related to PAP due to their indirect relationship to Shh-Gli3 signaling pathway. Initially, PAP may be the only clinical finding with ciliopathies so those cases need follow up. Proper diagnosis is helpful for management and genetic counseling. Molecular approach may help to define pleiotropy.
| S-EPMC4324078 | biostudies-literature
Project description:BackgroundPolydactyly is a common genetic limb deformity characterized by the presence of extra fingers or toes. This anomaly may occur in isolation (nonsyndromic) or as part of a syndrome. The disease is broadly divided into preaxial polydactyly (PPD; duplication of thumb), mesoaxial polydactyly (complex polydactyly), and postaxial polydactyly (PAP: duplication of the fifth finger). The extra digits may be present in one or both the limbs. Heterozygous variants in the GLI3, ZRS/SHH, and PITX1 have been associated with autosomal dominant polydactyly, while homozygous variants in the ZNF141, IQCE, GLI1, and FAM92A have been associated with autosomal recessive polydactyly. Pathogenic mutations in the GLI3 gene (glioma-associated oncogene family zinc finger 3) have been associated with both nonsyndromic and syndromic polydactyly.MethodsHere, we report an extended five generation kindred having 12 affected individuals exhibiting nonsyndromic postaxial polydactyly type A condition. Whole-exome sequencing followed by variant prioritization, bioinformatic studies, Sanger validation, and segregation analysis was performed.ResultsUsing exome sequencing in the three affected individuals, we identified a novel heterozygous frameshift variant (c.3567_3568insG; p.Ala1190Glyfs*57) in the transcriptional activator (TA2) domain of the GLI3 encoding gene.ConclusionTo the best of our knowledge, the present study reports on the first familial case of nonsyndromic postaxial polydactyly due to the GLI3 variant in Pakistani population. Our study also demonstrated the important role of GLI3 in causing nonsyndromic postaxial polydactyly.
| S-EPMC6625144 | biostudies-literature
Project description:Background: There have been many reports on the classification and treatment of postaxial polydactyly of the foot. However, despite its being a common congenital anomaly, there is no universal notation about its morphology. Methods: We performed an analysis of 65 postaxial polydactyly cases from 2004 to 2021. Judgment criteria for deciding the surgical procedure were selected, and the points required for notation were decided. Based on them, we devised a new notation. Results: The necessary points required for notation were decided based on the following criteria: (1) the presence and level of syndactyly, (2) bifurcation level of the phalanges, (3) the presence of other deformities, and (4) predominant toes. We came up with a new notation and description method. Different types of syndactyly were represented using a horizontal bar, and predominant toes were represented using equality or inequality symbols. The bifurcation level of the phalanges and accessory deformities were additionally recorded (eg, 4—5>—6, Middle, 5,6: External rotation). From this notation, it is obvious which toe should be resected. Furthermore, syndactyly, accessory deformities, and the condition of the phalanges are also easily understood. Conclusions: Our new notation for postaxial polydactyly consists of some related symbols that are each provided a meaning. This system is simple, especially for easily understanding the morphology, and ideal for daily medical use. We conclude that it could become a universal notation method for cases of postaxial polydactyly of the foot.
| S-EPMC9633084 | biostudies-literature
Project description:BackgroundPostaxial polydactyly is a common congenital foot anomaly. However, the severity of the anomaly varies from simple cases with only soft tissue duplication to complex cases with bone and joint disorders. In our clinical practice, we found a new morphological anomaly of postaxial polydactyly. We encountered several cases of postaxial polydactyly with bone fragments located between the fourth and fifth toes. The bone fragments were independent of the joint cavity. The mechanisms underlying its development remain unknown because it is a novel disorder. In the present study, we investigated the characteristics of the excess bone to formulate an embryological hypothesis.MethodsWe examined the frequency and trends in the occurrence of excess bone using data from photographs and radiographs of these cases. An example of a disorder similar to excess bone is mosaic-like alignment, as reported by Iba et al. We also compared the characteristics of the mosaic-like alignment with those of the excess bone. Based on these data and existing embryological knowledge, we hypothesized the origin of the excess bone.ResultsExcess bone and mosaic-like alignments showed different characteristics. Therefore, both were considered completely different disorders. We hypothesized that excess bone was caused by damage to the interdigital ectoderm immediately before interdigital programmed cell death.ConclusionsWe encountered a new form of postaxial polydactyly. This can be a factor influencing the treatment strategy because it can affect alignment and stability.
| S-EPMC11000771 | biostudies-literature
Project description:PurposeFanconi anemia (FA) genes play important roles in spermatogenesis. In mice, disruption of Fancm impairs male fertility and testicular integrity, but whether FANCM pathogenic variants (PV) similarly affect fertility in men is unknown. Here we characterize a Pakistani family having three infertile brothers, two manifesting oligoasthenospermia and one exhibiting azoospermia, born to first-cousin parents. A homozygous PV in FANCM (c.1946_1958del, p.P648Lfs*16) was found cosegregating with male infertility. Our objective is to validate that FANCM p.P648Lfs*16 is the PV causing infertility in this family.MethodsExome and Sanger sequencing were used for PV screening. DNA interstrand crosslink (ICL) sensitivity was assessed in lymphocytes from patients. A mouse model carrying a PV nearly equivalent to that in the patients (FancmΔC/ΔC) was generated, followed by functional analysis in spermatogenesis.ResultsThe loss-of-function FANCM PV increased ICL sensitivity in lymphocytes of patients and FancmΔC/ΔC spermatogonia. Adult FancmΔC/ΔC mice showed spermatogenic failure, with germ cell loss in 50.2% of testicular tubules and round-spermatid maturation arrest in 43.5% of tubules. In addition, neither bone marrow failure nor cancer/tumor was detected in all the patients or adult FancmΔC/ΔC mice.ConclusionThese findings revealed male infertility to be a novel phenotype of human patients with a biallelic FANCM PV.
| S-EPMC6752308 | biostudies-literature
Project description:Postaxial polydactyly is a common congenital malformation which involves complex genetic factors. This retrospective study analyzed the cytogenetic and molecular results of a Chinese fetus diagnosed with postaxial polydactyly of all four limbs. Fetal karyotyping and chromosomal microarray analysis (CMA) did not find any abnormality while trio whole-exome sequencing (trio-WES) identified bi-allelic variants in smoothened (SMO) and (NM_005631.5: c.1219C > G, NP_005622.1: p. Pro407Ala, and NM_005631.5: c.1619C > T, NP_005622.1: p. Ala540Val). Sanger sequencing validated these variants. The mutations are highly conserved across multiple species. In-depth bioinformatics analysis and familial co-segregation implied the compound heterozygous variants as the likely cause of postaxial polydactyly in this fetus. Our findings provided the basis for genetic counseling and will contribute to a better understanding of the complex genetic mechanism that underlies postaxial polydactyly.
| S-EPMC9257524 | biostudies-literature
Project description:Apparently balanced chromosomal inversions may lead to disruption of developmentally important genes at the breakpoints of the inversion, causing congenital malformations. Characterization of such inversions may therefore lead to new insights in human development. Here, we report on a de novo inversion of chromosome 7 (p15.2q36.3) in a patient with postaxial polysyndactyly. The breakpoints do not disrupt likely candidate genes for the limb phenotype observed in the patient. However, on the p-arm the breakpoint separates the HOXA cluster from a gene desert containing several conserved noncoding elements, suggesting that a disruption of a cis-regulatory circuit of the HOXA cluster could be the underlying cause of the phenotype in this patient.
| S-EPMC2759026 | biostudies-literature
Project description:BACKGROUND:Zhu-Tokita-Takenouchi-Kim syndrome is a severe multisystem developmental disorder characterized by intellectual disability, developmental delay, malformations of the cerebral cortex, epilepsy, vision problems, musculoskeletal abnormalities, and congenital malformations. This syndrome is caused by heterozygous pathogenic variants in the SON gene at chromosome 21q22.1. OBJECTIVES:The aim of this study was to investigate the pathogenesis of a 4-year-old Chinese child who displayed severe intellectual disability, delayed psychomotor development, and facial dysmorphism. METHODS:A sequential detection including chromosome karyotyping, chromosome microarray analysis (CMA), and whole-exome sequencing (WES) was performed on this child. The familial verification of WES result was conducted by Sanger sequencing. RESULTS:A de novo frameshift variant SON: c.5230delC (p.Arg1744ValfsTer29) was identified in the proband. The identical variant was not found in his family members. The frequencies of this variant in gnomAD/gnomAD_EAS databases were both none. CONCLUSIONS:This study substantiates that SON: c.5230delC (p.Arg1744ValfsTer29) is a pathogenic variant of Zhu-Tokita-Takenouchi-Kim syndrome and it is the first time to report Zhu-Tokita-Takenouchi-Kim syndrome in China.
| S-EPMC7439338 | biostudies-literature
Project description:Polydactyly is a highly common congenital limb defect. Extra digits may appear as an isolated anomaly or as a part of a syndrome. Mutations in GLI3 have been shown to cause Greig cephalopolysyndactyly, Pallister-Hall syndrome and non-syndromic polydactyly. Genotype-phenotype correlation studies of GLI3 mutations suggest a model by which mutations in the zinc-finger domain (ZFD) of GLI3 likely lead to syndromic polydactyly. Here we describe a rare case of autosomal dominant heterozygous missense mutation in the ZFD of GLI3 leading to a variable polydactyly-syndactyly complex.A large Jewish Moroccan family presented with apparently autosomal dominant heredity of bilateral thumb polydactyly in hands and feet combined with post-axial polydactyly type B or type A. Syndactyly was evident in most patients' hands and feet. Apart from head circumference beyond 90th percentile in some of the affected individuals, none had craniofacial dysmorphism. A novel GLI3 c.1802A >?G (p.His601Arg) mutation was found in all affected individuals.We demonstrate that a mutation in the ZFD domain of GLI3 leads to phenotypic variability, including an isolated limb phenotype. Thus, the variability in phenotypes caused by mutations in this master developmental regulator is more profound than has been previously suggested.
| S-EPMC4256830 | biostudies-literature