Polydactyly: Clinical and molecular manifestations

Abstract

Polydactyly is a malformation during the development of the human limb, which is characterized by the presence of more than the normal number of fingers or toes. It is considered to be one of the most common inherited hand disorders. It can be divided into two major groups: Non-syndromic polydactyly or syndromic polydactyly. According to the anatomical location of the duplicated digits, polydactyly can be generally subdivided into pre-, post-axial, and mesoaxial forms. Non-syndromic polydactyly is often inherited with an autosomal dominant trait and defects during the procedure of anterior-posterior patterning of limb development are incriminated for the final phenotype of the malformation. There are several forms of polydactyly, including hand and foot extra digit manifestations. The deformity affects upper limbs with a higher frequency than the lower, and the left foot is more often involved than the right. The treatment is always surgical. Since the clinical presentation is highly diverse, the treatment combines single or multiple surgical operations, depending on the type of polydactyly. The research attention that congenital limb deformities have recently attracted has resulted in broadening the list of isolated gene mutations associated with the disorders. Next generation sequencing technologies have contributed to the correlation of phenotype and genetic profile of the multiple polydactyly manifestations and have helped in early diagnosis and screening of most non-syndromic and syndromic disorders.

Whole-Genome Sequencing for Identifying Candidate Genes Related to the Special Phenotypes of the Taihu Dianzi Pigeon

“…Extensive research has been conducted on polydactyly traits in humans [44], mice [45], and chickens [13], and various types of polydactylies have been classified. Pigeons are commonly four-toed, while the polydactyl Taihu Dianzi pigeons have extra toes on the outside of the inner toe of one or two feet, which is similar to the preaxial polydactyly [46]. Polydactyly in chickens occurs mainly on the short arm of chromosome 2, which harbors many candidate genes, such as SHH, Lmbr1, and Gli3 [47,48].…”

Identification of a novel IQCE variant in a Korean patient with nonsyndromic postaxial polydactyly

“…Postaxial polydactyly (PAP) affects the ulnar side, typically involving the first digit, whereas central polydactyly affects the second to fourth digits and preaxial polydactyly affects the radial side, involving the fifth digit. PAP is the most common type, followed by preaxial polydactyly, whereas central polydactyly is the least common type and is often associated with syndactyly (Kyriazis et al , 2023).…”