The EDA gene, located at Xq12-q13.1 and encoding the transmembrane type II ectodysplasin-A (EDA) protein, which belongs to the tumor necrosis factor superfamily, is responsible for XLHED through EDA-EDAR (EDA receptor)-EDARADD (EDAR-associated death domain) pathway [12, 13].. This evidence concerns the gene EDA and X-linked hypohidrotic ectodermal dysplasia.