Familial deletion of Xp21.2 with glycerol kinase deficiency and congenital adrenal hypoplasia

Summary Congenital adrenal hypoplasia (CAH) and glycerol kinase deficiency (GKD) were diagnosed in a male during the neonatal period. On prometaphase chromosomes there was an interstitial deletion involving Xp21.2 and possibly Xp21.3 in the propositus and his mother. Duchenne muscular dystrophy (DMD) was excluded on the basis of normal serum creatine kinase and a muscle biopsy. Molecular hybridization of DNA from the propositus with 11 probes covering Xp21, including the DMD locus, was normal. In situ hybridization with the probe pERT87.15 showed a normal signal at the expected site indicating that the DMD locus was preserved and not translocated. This suggests that the DMD locus is located at the most proximal part of the sub-band Xp21.2 or in Xp21.1, and that the DXS68 (probe L1) is far from it on the distal flanking DNA.