Blood, Vol. 93 No. 6 (March 15), 1999:
pp. 2098-2104
Missense Mutations in the gp91-phox Gene Encoding Cytochrome
b558 in Patients With Cytochrome b Positive
and Negative X-Linked Chronic Granulomatous Disease
Mizuho Kaneda,
Hitoshi Sakuraba,
Akira Ohtake,
Akira Nishida,
Chika Kiryu, and
Katsuko Kakinuma
From the Departments of Inflammation Research and Clinical Genetics,
The Tokyo Metropolitan Institute of Medical Science, Tokyo; the
Department of Clinical Pathology, Kitasato University School of
Medicine, Kanagawa; the Department of Veterinary Clinical Sciences,
Graduate School of Veterinary Medicine, Hokkaido University, Sapporo;
and the Biophotonics Information Laboratories, Yamagata Advanced
Technology Research Center, Yamagata, Japan.
Chronic granulomatous disease (CGD) is a disorder of host defense
due to genetic defects of the superoxide (O2-)
generating NADPH oxidase in phagocytes. A membrane-bound
cytochrome b558, a heterodimer consisting of
gp91-phox and p22-phox, is a critical component of the
oxidase. The X-linked form of the disease is due to defects in the
gp91-phox gene. We report here biochemical and genetic analyses
of patients with typical and atypical X-linked CGD. Immunoblots showed
that neutrophils from one patient had small amounts of p22-phox
and gp91-phox and a low level of O2-
forming oxidase activity, in contrast to the complete absence of both
subunits in two patients with typical CGD. Using polymerase chain
reactions (PCR) on cDNA and genomic DNA, we found novel missense
mutations of gp91-phox in the two typical patients and a point
mutation in the variant CGD, a characteristic common to two other
patients with similar variant CGD reported previously. Spectrophotometric analysis of the neutrophils from the variant patient
provided evidence for the presence of heme of cytochrome b558. Recently, we reported another variant CGD
with similar amounts of both subunits, but without oxidase activity or
the heme spectrum. A predicted mutation at amino acid 101 in
gp91-phox was also confirmed in this variant CGD by PCR of the
genomic DNA. These results on four patients, including those with two
variant CGD, are discussed with respect to the missense mutated sites
and the heme binding ligands in gp91-phox.
