AUTHOR=Umair Muhammad , Ahmad Farooq , Bilal Muhammad , Ahmad Wasim , Alfadhel Majid 

TITLE=Clinical Genetics of Polydactyly: An Updated Review

JOURNAL=Frontiers in Genetics

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2018.00447

DOI=10.3389/fgene.2018.00447

ISSN=1664-8021

ABSTRACT=<p>Polydactyly, also known as <italic>hyperdactyly</italic> or <italic>hexadactyly</italic> is the most common hereditary limb anomaly characterized by extra fingers or toes, with various associated morphologic phenotypes as part of a syndrome (syndromic polydactyly) or may occur as a separate event (non-syndromic polydactyly). Broadly, the non-syndromic polydactyly has been classified into three types, i.e.; preaxial polydactyly (radial), central polydactyly (axial), and postaxial polydactyly (ulnar). Mostly inherited as an autosomal dominant entity with variable penetrance and caused by defects that occur in the anterior-posterior patterning of limb development. In humans, to-date at least 10 loci and six genes causing non-syndromic polydactyly have been identified, including the <italic>ZNF141</italic>, <italic>GLI3</italic>, <italic>MIPOL1</italic>, <italic>IQCE</italic>, <italic>PITX1</italic>, and the <italic>GLI1</italic>. In the present review, clinical, genetic and molecular characterization of the polydactyly types has been presented including the recent genes and loci identified for non-syndromic polydactyly. This review provides an overview of the complex genetic mechanism underlie polydactyly and might help in genetic counseling and quick molecular diagnosis.</p>