Mutational spectrum of NSDHL in CHILD syndrome

Abstract

A related trait, X linked dominant chondrodysplasia punctata (CDPX2, MIM 302960),²² is caused by mutations in EBP (emopamil binding protein) at Xp11.22–p11.23 that functions similarly in the late cholesterol biosynthesis, downstream of NSDHL.^{23, 24} In the past, a case of X linked dominant chondrodysplasia punctata showing unilateral involvement was mistaken as an example of CHILD syndrome.²⁵ Because abnormal sterol patterns suggestive of an EBP mutation were found, the investigators erroneously concluded that CHILD syndrome is genetically heterogeneous. In fact, their case had all the clinical features of X linked dominant chondrodysplasia punctata but none of the morphological criteria of CHILD syndrome.^{1, 22} Hence there is so far no case report of CHILD syndrome showing a mutation outside the NSDHL locus.