Molecular genetic studies of two families with X-linked chronic granulomatous disease: mutation analysis and definitive determination of carrier status in patients' sisters.

Molecular genetic studies of two families with X-linked chronic granulomatous disease (X-CGD) were performed. The patients showed abnormal patterns on Southern blot analysis using cytochrome b heavy chain (CYBB) cDNA as a probe. Both patterns differed and neither has ever been observed in normal individuals. We applied the results to the diagnosis of the carrier state in the patients' sisters. The results clearly demonstrated that each patient's sister possessed the same abnormal allele as the patient's CYBB gene, as detected by Southern analysis. Thus, the results confirm that both of the patients' sisters are carriers of the disease. Further molecular analysis of the patients' mutation revealed that they were a point mutation, and a partial deletion of the CYBB gene, respectively. These mutations have not previously been reported.