Identification of a novel DLX5 mutation in a family with autosomal recessive split hand and foot malformation

Background Split hand and foot malformation (SHFM) refers to a genetically heterogeneous developmental disorder of the hands and feet that presents as median ray deficiency of varying severity. 7q21.3 (SHFM1) is one of six loci described to date, and although DLX5 and DLX6 are compelling candidates in that locus, no intragenic mutations have been described in either of these genes. Methods The authors combined autozygome analysis and exome sequencing to study a consanguineous family with a highly unusual SHFM phenotype, where there is associated dorsalisation of the hands. Results A novel missense mutation in a highly conserved residue of the homeobox domain of DLX5 was identified. Unlike previously reported position effect mutations in SHFM1, this first documented intragenic DLX5 mutation is also accompanied by abnormal dorsal-ventral patterning. Conclusion This study identified the first intragenic DLX5 mutation in SHFM and raises interesting possibilities about a dual role for DLX5 in limb development.