A 25-KB DELETION IN THE 5'-REGION OF THE CYTOCHROME B(558) HEAVY-CHAIN GENE (CYBB) IN A PATIENT WITH X-LINKED CHRONIC GRANULOMATOUS-DISEASE

We performed molecular genetic analyses of the family of a boy sufferi ng from chronic granulomatous disease (CGD) after immunocytochemically confirming him and his mother to be an X-linked CGD patient and a mos aic carrier, respectively. Southern blot hybridization using cDNA for the cytochrome b(558) heavy chain gene (CYBB) as a probe showed that t he patient had a deletion in the 5' region of the CYBB and his phenoty pically normal mother was heterozygous for this deletion. Polymerase c hain reaction analyses of all 13 exons of the patient's CYBB gene demo nstrated that the deletion extends from exon 7 or neighboring introns to 5' upstream. The length of the deletion was determined by pulsed-fi eld gel electrophoresis and Southern blotting of genomic DNA using CYB B cDNA and the genetic marker pERT55-5, centromeric to CYBB, as probes . Both probes recognized common SfiI-NotI fragments of 120 kb and 95 k b in normal individuals and the patient, respectively. These results r evealed that the patient has a 25-kb deletion spanning from the middle of CYBB to 5' upstream. This is the only report of a large 5' deletio n in CYBB and also the first observation that CYBB and pERT55-5 are wi thin 120 kb in Xp21.