In a patient suffering from X-linked chronic granulomatous disease (X-CGD)--a 
disorder of phagocytesuperoxide generation--and McLeod syndrome, characterized 
by the absence of the red cell Kell antigen, we identified a deletion of the 
entire X-CGD gene by means of DNA hybridization with a cDNA probe. Our findings 
suggest that the X-CGD and McLeod loci are physically close in the p21 region of 
the X chromosome proximal to the Duchenne muscular dystrophy locus.