DLX homeobox genes are mammalian homologs of the Drosophila Distal-less (DLL) gene and consist of six genes that are divided into Dlx1/2,Dlx5/6, and Dlx3/7 bi-gene clusters. DLX5 gene encodes a transcriptional factor protein which is expressed mainly in early embryonic development and has an important role in limb, craniofacial and head development and sensory organ morphogenesis. It also has an important role in regulating the development of γ-aminobutyric acid (GABA)-ergic neurons.
Defects in this protein are the cause of split-hand/foot malformation 1 with sensorineural hearing loss, an autosomal recessive disease characterized by limb malformation involving the central rays of the autopod and presenting with syndactyly, median clefts of the hands and feet, and aplasia and/or hypoplasia of the phalanges, metacarpals, and metatarsals.