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Background Polydactyly is one of the most common congenital hand/foot malformations in humans. Mutations in GLI3 have been reported to cause syndromic and non-syndromic forms of preaxial and postaxial polydactylies. Case presentation The patient was a 2-year-old boy who underwent surgery in our hospital. The right hand and left foot of the patient were labelled as postaxial polydactyly type B, and there was cutaneous webbing between the 3rd and 4th fingers of the left hand. We identified a novel c. 1622C > T variant in GLI3 leading to an isolated postaxial synpolydactyly. Conclusions The patient carries a novel autosomal dominant heterozygous missense mutation. This mutation c.1622C > T;p.(Thr541Met) in the GLI3 gene may affect the normal function of the zinc finger domain (ZFD) in a different way. However, it seems that more research is needed to determine the exact effects of this mutation.

This case series describes a novel condition characterized by familial pseudotail associated with scoliosis, and synpolydactyly that has not been previously reported in literature. The authors present three siblings and one cousin from the same family living in the northern region of the Arabian Peninsula. All cases presented with pseudotail, scoliosis, and complex synpolydactyly. The authors demonstrated complete clinical and radiological descriptions in addition the detailed performed surgeries. The histopathological result of the resected pseudotail specimens revealed bony lesion covered with thick fibrous tissue and evidence of mature adipocytes within trabecular spaces. The described cases represent a novel condition that has not been previously reported in the literature. Familial pseudotail scoliosis synpolydactyly syndrome is a newly recognized form of familial pseudotail.

On March 23, 2010, we successfully treated a boy with synpolydactyly who had a total of 31 fingers and toes. Although there was bone syndactyly both the hands of the boy, one-step correction of four extremities was successful, this operation lasted 5 h and 20 min and intraoperative bleeding was about 50 ml. Skin grafting was successful after operation and all incisions healed well. The appearance and function of hands and feet were satisfactory.

Background Bardet Biedl Syndrome (BBS) is a rare condition of multi-organ dysfunction with characteristic clinical features of retinal degeneration, truncal obesity, postaxial polydactyly, genital anomaly, intellectual disability and renal dysfunction. It is a hetero-genetic disorder and nineteen BBS genes have been discovered so far. Methods Whole genome SNP genotyping was performed by using CytoScan® 750 K array (Affymetrix). Subsequently, the segregation of the disease locus in the whole family was carried out by genotyping STS markers within the homozygous interval. Finally, the mutation analysis was performed by Sanger DNA sequencing. Results In the present molecular study a consanguineous Pakistani family, with autosomal recessive BBS, was analyzed. The clinical analysis of affected individuals presented with synpolydactyly, obesity, intellectual disability, renal abnormality and retinitis pigmentosa. The presented phenotype was consistent with the major features of BBS syndrome. Homozygosity mapping identified a common homozygous interval within the known BBS9 locus. Sequence analysis of BBS9/PTHB1 gene revealed a single base deletion of c.299delC (p.Ser100Leufs*24) in exon 4. This frame-shift mutation presumably leads to a 122 amino acid truncated protein with complete loss of its C-terminal PTHB1 domain in combination with a partial loss of the N-terminal PTHB1 domain as well. BBS9/PTHB1 gene mutations have been shown to be associated with BBS syndrome and to the best of our knowledge this study reports the first Pakistani family linked to the BBS9 gene. Conclusion Our molecular findings expand the mutational spectrum of BBS9 gene and also explain the genetic heterogeneity of Pakistan families with BBS syndrome. The growing number of mutations in BBS genes in combination with a detailed phenotypical description of patients will be helpful for genotype-phenotype correlation, targeted genetic diagnosis, prenatal screening and carrier testing of familial and non-familial BBS patients.

Hand-foot-genital syndrome (HFGS) is a dominantly inherited congenital malformation affecting the distal limbs and genitourinary tract. Here, we describe the phenotype and its molecular basis in a family that presented with HFGS. Genetic analysis revealed that the condition is caused by an 18-bp in-frame duplication within a cryptic trinucleotide repeat sequence encoding an 18-residue polyalanine tract in the homeoboxgene ( HOX) A13. This mutation expands the stretch with six extra alanine residues. Similar types of mutation (plus eight alanines) have recently been found in another HFGS family and also in the human HOXD13 gene (plus seven up to plus 14 residues) where it leads to synpolydactyly (SPD), a further congenital limb malformation rarely associated with genital abnormalities. As observed in our family, all the expanded tracts encoding polyalanine, either reported for HOXA13 or HOXD13, are quite stable when transmitted within affected families. Unlike disorders with unstable expansions of perfect trinucleotide repeats the molecular mechanism underlying these polyalanine expansions should be unequal crossing-over rather than replication slippage. The alanine tract elongation may prevent protein-protein interactions of the mutant HOXA13, thereby inducing a localized heterochrony in the sequence of distal limb and genitourinary development.

Hypodactyly (Hd) is a semidominant mutation in mice that maps in a genetic interval overlapping the Hoxa cluster. The profound deficiency of digital arch structures in Hd/Hd mice is consistent with a defect in a gene activated late in limb morphogenesis. We have determined the structure of the Hoxa13 gene and describe a 50-base pair deletion in the first exon of the Hd allele that probably arose from unequal recombination or misalignment between triplet repeats. It is predicted that no Hoxa13 protein is made from Hd mRNA. The hypodactyly limb phenotype is similar to that of Hoxd13-deficient mice in sharing defects along multiple axes and alterations in cartilage maturation; however, the overall effects on digital arch formation are more severe in Hd/Hd mice. Our results confirm the critical role of AbdB-like Hox genes in the development of the autopod, and add to the spectrum of mutations involving triplet repeats.