title: Advances in the Molecular Genetics of Non-syndromic Syndactyly.
abstract: Syndactyly, webbing of adjacent digits with or without bony fusion, is one of the most common hereditary limb malformations. It occurs either as an isolated abnormality or as a component of more than 300 syndromic anomalies. There are currently nine types of phenotypically diverse nonsyndromic syndactyly. Non-syndromic syndactyly is usually inherited as an autosomal dominant trait, although the more severe presenting types and subtypes may show autosomal recessive or X-linked pattern of inheritance. The phenotype appears to be not only caused by a main gene, but also dependant on genetic background and subsequent signaling pathways involved in limb formation. So far, the principal genes identified to be involved in congenital syndactyly are mainly involved in the zone of polarizing activity and sonic hedgehog pathway. This review summarizes the recent progress made in the molecular genetics, including known genes and loci responsible for non-syndromic syndactyly, and the signaling pathways those genetic factors involved in, as well as clinical features and animal models. We hope our review will contribute to the understanding of underlying pathogenesis of this complicated disorder and have implication on genetic counseling.
authors.affiliation: Center for Experimental Medicine ; Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Deng
authors.affiliation: Center for Experimental Medicine.
authors.forename: Ting
authors.initials: T
authors.lastname: Tan
keywords: Heterogeneity; Limb malformation; Molecular genetics; Mutation; Syndactyly; Webbed digits