Isolated hexadactylia: A rare case of central polydactyly of the foot

BackgroundCentral polydactyly of foot is uncommon form of polydactyly but it usually causes intermetatarsal widening because of metatarsal bifurcation. Central polydactyly associated with T shaped bifurcation of metatarsal in vertical plane has not been reported yet.CaseWe present a 4 year male child with extra toe on the dorsal aspect of right foot with complains of difficulty in wearing footwear and poor cosmesis. The extra digit was fully developed with bifurcation of 2^nd metatarsal bone proximal to the head without any intermetatarsal widening. The angular deviation was 45° to the longitudinal axis of foot and in a plane vertical to the transverse arch of foot. The child was operated with excision of extra toe without any residual bony deformity.ConclusionThe central polydactyly is rare type of polydactyly of foot. Central polydactyly with metatarsal extension causing intermetatarsal widening has been well described entity. But the previous classifications need to be modified to include central polydactyly with vertical oriented T bifurcation of metatarsal bone without intermetatarsal widening.     

Loss of function IFT27 variants associated with an unclassified lethal fetal ciliopathy with renal agenesis

Ciliopathies comprise a group of clinically heterogeneous and overlapping disorders with a wide spectrum of phenotypes ranging from prenatal lethality to adult‐onset disorders. Pathogenic variants in more than 100 ciliary protein‐encoding genes have been described, most notably those involved in intraflagellar transport (IFT) which comprises two protein complexes, responsible for retrograde (IFT‐A) and anterograde transport (IFT‐B). Here we describe a fetus with an unclassified severe ciliopathy phenotype including short ribs, polydactyly, bilateral renal agenesis, and imperforate anus, with compound heterozygosity for c.118_125del, p.(Thr40Glyfs*11) and a c.352 +1G > T in IFT27, which encodes a small GTPase component of the IFT‐B complex. We conclude that bilateral renal agenesis is a rare feature of this severe ciliopathy and this report highlights the phenotypic overlap of Pallister–Hall syndrome and ciliopathies. The phenotype in patients with IFT27 gene variants is wide ranging from Bardet–Biedl syndrome to a lethal phenotype.     

An unusual case of preaxial polydactyly of the hand (triplication of the thumbs)

Preaxial polydactyly is the most common duplication pattern in white and Asian populations (1). It is a congenital anomaly with a wide range of manifestations. Current classification do not have the capacity to classify all different types of radial polydactyly. We describe here a very rare and unusual case of bilateral preaxial polydactyly (triplication) in a woman and report the operations results. We have not found similar case in the literature. Our case is unique and did not fit into the classification systems described for thumb polydactyly.     

On-top and side-to-side plasties for thumb polydactyly

Introduction“On-top” and “side-to-side” plasties are techniques used for treating thumb duplications in which one thumb is adequate proximally and the other thumb contains a better pulp and nail distally. The detailed functional results of these techniques have not been reported in the literature. We report on two cases.Presentation of casesThe first case had Wassel type VI duplication. The ulnar duplicate had a functioning interphalangeal joint and the radial duplicate had a functioning carpometacarpal joint. “On-top” plasty was done by putting the distal part of the ulnar duplicate on top of the proximal part of the radial duplicate. At 10 years after surgery, the outcome was excellent both cosmetically and functionally. In the second case (Wassel type VII with a zigzag deformity), the radial duplicate had a hypoplastic distal phalanx with no nail. The ulnar duplicate had a functioning interphalangeal joint and the radial duplicate had a functioning carpometacarpal joint. “Side-to-side” plasty was done by joining both thumbs side-to-side at the level of the proximal phalanx. At 3 years after surgery, the outcome we considered acceptable cosmetically and excellent functionally.DiscussionWe could not find similar cases in the literature with detailed long-term postoperative results.Conclusion“On-top” and “side-to-side” plasties in the management of specific cases of thumb polydactyly obtain excellent functional results with excellent or acceptable cosmetic outcome.     

GLI3基因新发突变致多指（趾）畸形一家系

目的 对1个先天性多指（趾）畸形家系进行GLI家族锌指3基因（GLI3）突变分析,进一步丰富GLI3的突变谱。方法 收集1例临床诊断为多指（趾）畸形的患儿资料,提取患儿外周血DNA,应用全外显子测序方法检测与患儿症状相关的致病基因,并在家系其他成员中应用Sanger测序进行验证。结果 该家系中包括患儿在内的4位多指（趾）畸形患者位于7p14.1的GLI3基因存在c.2783delG（p.Arg928Profs24X）框移突变。在该家系的正常成员中未检测到该位点突变。经查询HGMD、Clinvar及dbSNP数据库均未见相关报道。该病例多指（趾）畸形诊断明确,其突变位 点为新突变。GLI3基因的c.2783delG（p.Arg928Profs24X）框移突变可能为该家系的发病原因。结论 本研究发现新发突变 GLI3［c.2783delG（p.Arg928Profs24X）］,进一步丰富了 GLI3基因的突变谱,为深入研究多指（趾）畸形的发病机制提供了新的内容。     

Mutation analysis of a large Chinese pedigree with congenital preaxial polydactyly

Mutations in the long-range limb-specific cis-regulator (ZRS) could cause ectopic shh gene expression and are responsible for preaxial polydactyly (PPD). In this study, we analyzed a large Chinese isolated autosomal dominant PPD pedigree. By fine mapping and haplotype construction, we located the linked region to a 1.7 cM interval between flanking markers D7S2465 and D7S2423 of chromosome 7q36. We directly sequenced the candidate loci in this linked region, including the coding regions of the five genes (HLXB9, LMBR1, NOM1, RNF32 and C7orf13), the regulatory element (ZRS) of shh, the whole intron 5 of LMBR1 which contained the ZRS, and 18 conserved noncoding sequences (CNSs). Interestingly, no pathogenic mutation was identified. By using real-time quantitative PCR (qPCR), we also excluded the ZRS duplication in this pedigree. Our results indicate that, at least, it is not the mutation in a functional gene, CNS region or duplication of ZRS that cause the phenotype of this pedigree. The etiology of this PPD family still remains unclear and the question whether another limb-specific regulatory element of shh gene exists in the noncoding region in this 1.7 cM interval remains open for future research.