Spectrally abnormal cytochrome-b in a male patient with chronic granulomatous disease

Cytochrome-b and flavin adenine dinucleotide (FAD) were measured in neutrophils from a male patient and his family with the X-linked form of Chronic Granulomatous Disease (CGD). The membrane fraction of the patient's neutrophils contained 93pmol/mg protein of FAD (control 102±20, mean±sd), and 32pmol/mg protein of cytochrome-b (control 88±20, mean±sd). In the spectrophotometric study, the maximal absorbance peak of cytochrome-b was at 421nm, as that from control was at 427nm. Cytochrome-b in neutrophils from his mother and a sister, who were thought to be carriers, had their maximal absorbance peak at 425nm. These findings suggest that the spectral abnormality of cytochrome-b contribute to the pathogenesis of CGD in this case.