Polydactyly is one of the most common inherited limb abnormalities, characterised by supernumerary fingers or toes. It results from disturbances in the normal programme of the anterior–posterior axis of the developing limb, with diverse aetiology and variable inter- and intra-familial clinical features. Polydactyly can occur as an isolated disorder (non-syndromic polydactyly) or as a part of an anomaly syndrome (syndromic polydactyly). On the basis of the anatomic location of the duplicated digits, non-syndromic polydactyly is divided into three kinds, including preaxial polydactyly, axial polydactyly and postaxial polydactyly. Non-syndromic polydactyly frequently exhibits an autosomal dominant inheritance with variable penetrance. To date, in human, at least ten loci and four disease-causing genes, including the GLI3 gene, the ZNF141 gene, the MIPOL1 gene and the PITX1 gene, have been identified. In this paper, we review clinical features of non-syndromic polydactyly and summarise the recent progress in the molecular genetics, including loci and genes that are responsible for the disorder, the signalling pathways that these genetic factors are involved in, as well as animal models of the disorder. These progresses will improve our understanding of the complex disorder and have implications on genetic counselling such as prenatal diagnosis.

中文翻译：

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非综合征型多指畸形分子遗传学研究进展

多指畸形是最常见的遗传性肢体异常之一，其特征是多指手指或脚趾。它是发育中肢体前后轴正常程序紊乱的结果，具有多种病因和不同的家族间和家族内临床特征。多指症可以作为一种孤立的疾病（非综合征性多指症）或作为异常综合征的一部分（综合征性多指症）发生。根据重指的解剖位置，非综合征性多指畸形分为轴前多指、轴后多指和轴后多指三种。非综合征性多指症经常表现出具有可变外显率的常染色体显性遗传。迄今为止，在人类中，至少有 10 个位点和 4 个致病基因，包括GLI3基因ZNF141基因MIPOL1基因和PITX1基因，已确定。在本文中，我们回顾了非综合征性多指畸形的临床特征，并总结了分子遗传学的最新进展，包括导致该疾病的位点和基因、这些遗传因素参与的信号通路以及动物模型。的紊乱。这些进展将提高我们对复杂疾病的理解，并对产前诊断等遗传咨询产生影响。