Array CGH study confirmed the existence of a deletion in Xp21 of the genes responsible for DMD, GKD and the congenital adrenal hypoplasia (gene DAX1 or NROB1 gene: Xp21.3-21.2).
For example, the map suggests that the adrenal hypoplasia congenita and glycerol kinase genes are physically close to each other, are within 1-2 Mb of the telomeric end of the Duchenne muscular dystrophy (DMD) gene, and are nearer to the DMD locus than to the more distal marker DXS28 (C7).
One of the boys with DMD, GK, and AHC is shown by pulsed-field-gel electrophoresis to have a deletion which has a proximal endpoint at least 500 kb distal from the pERT87 (DXS164) locus.