CHILD syndrome caused by deficiency of 3 beta-hydroxysteroid-Delta(8), Delta(7)-isomerase

CHILD (congenital hemidysplasia, ichthyosis, and Limb defects) syndrome is a rare, usually sporadic disorder associated with unilateral distribution o f ichthyosiform skin lesions, limb defects, punctate calcifications of cart ilaginous structures, and visceral anomalies, CHILD syndrome shares some ma nifestations with X-linked dominant Conradi-Hunermann syndrome (CDPX2), alt hough the skeletal defects and skin lesions in CDPX2 are bilateral and asym metric. Because CDPX2 patients have abnormal 8-dehydrosterol metabolism cau sed by mutations in 3 beta-hydroxysteroid-Delta(8),Delta(7)-isomerase, we m easured plasma sterols in a patient with CHILD syndrome and found levels of 8-dehydrocholesterol and 8(9)-cholestenol increased to the same degree as in CDPX2 patients. Subsequently, we identified a nonsense mutation in exon 3 of the patient's 3 beta-hydroxysteroid-Delta(8),Delta(7)- isomerase gene. We speculate that at least some cases of CHILD syndrome are allelic with C DPX2 caused by 3 beta-hydroxysteroid-Delta(8),Delta(7)-isomerase deficiency . (C) 2000 Wiley-Liss, Inc.