Abstract: Syndactyly (SD) is one of the most common hereditary limb malformations depicting the fusion of certain fingers or toes. It may occur as an isolated entity or a component of more than 300 syndromic anomalies. Syndactylies exhibit great inter- and intra-familial clinical variability. Phenotype can be unilateral or bilateral and symmetrical or asymmetrical within a subject. At least nine non-syndromic syndactylies have been characterized. Most of the syndactyly types are inherited as autosomal dominant but two autosomal recessive and an X-linked recessive entity have also been described. Whereas the underlying genes/mutations for types Ⅱ-a, Ⅲ, Ⅳ, Ⅴ, Ⅶ and Ⅷ have been worked out, the etiology and molecular basis of the other syndactyly types remain unknown. In this communication, based on the classification of Sajid Malik, we summarized the results of genetic studies on syndactyly in recent years, which will contribute to further investigation of the pathogenic mechanism and implementation of genetic diagnosis of syndactyly.

Key words: Congenital abnormalities, Syndactyly, Genetic diseases, inborn, Genetic heterogeneity