Identification of a novel mutation in 3beta-hydroxysteroid-Delta8-Delta7-isomerase in a case of Conradi-Hünermann-Happle syndrome.

The X-linked dominant Conradi-Hünermann-Happle (CDPX2, MIM 302960) syndrome belongs to the rare, heterogeneous group of diseases called chondrodysplasia punctata. The disease has been connected recently with deficiency of 3beta-hydroxysteroid-Delta8-Delta7-isomerase (also called emopamil-binding protein, EBP), catalysing an intermediate step in the conversion of lanosterol to cholesterol (1, 2). We report a case of CDPX2 with a new missense mutation (C-->G 439) in exon 4, leading to a R147G aminoacid substitution in the EBP.