Novel frame-shift mutations of GLI3 gene in non-syndromic postaxial polydactyly patients

Polydactyly is a common congenital limb deformity. This anomaly may occur in isolation (non-syndromic) or as part of a syndrome. The glioma-associated oncogene family zinc finger 3 (GLI3) is known to be associated with both syndromic and non-syndromic polydactyly. GLI3 plays a predominant role in the pathogenesis of syndromic polydactyly: mutations have been identified in 68% of patients with Greig cephalopolysyndactyly syndrome and 91% of patients with Pallister-Hall syndrome. The knowledge regarding the contribution of GLI3 in non-syndromic polydactyly is currently very limited. In this study, we assembled a cohort of individuals of Chinese ethnicity with non-syndromic postaxial polydactyly. We presented the clinical features and molecular evaluations of 19 probands. GLI3 mutations were identified in 15.8% of probands (3/19) including two novel frame-shift mutations c.3855dupC (p.Met1286HisfsTer18) and c.4141delA (p.Arg1381GlyfsTer38) detected in sporadic cases and one previously reported nonsense mutation (c.1927C > T/p.Arg643Ter) in a familial case. Of note, GLI3 mutations were exclusively detected in patients with bilateral polydactyly affecting both hands and feet. Three out of five (60%) probands with bilateral polydactyly on both hands and feet carried pathogenic mutations in GLI3. Our study demonstrated the role of GLI3 in a significant fraction of patients with non-syndromic bilateral polydactyly affecting both hands and feet.