Genetic Variants of Chronic Granulomatous Disease: Prevalence of Deficiencies of Two Cytosolic Components of the NADPH Oxidase System

Abstract

Chronic granulomatous disease, a syndrome of recurrent infections and failure of oxidative microbicidal activity in phagocytes, results from defects in the gene for one of several components of an oxidase system that can undergo activation. To determine the relative prevalence of certain of the genetic variants of this disorder, we used immunoblotting to detect two specific neutrophil cytosolic proteins of 47 and 67 kd recently shown to be required for oxidase activation. Chronic granulomatous disease is usually an X-linked disorder associated with the absence of membrane cytochrome b558. Of our 94 patients with chronic granulomatous disease, however, 36 had a phenotype characterized by autosomal inheritance, normal membrane oxidase components (including cytochrome b558), and functionally defective cytosolic activity in a cell-free oxidase system. We studied 25 of these 36 patients and found that 22 lacked the 47-kd cytosolic protein, and the remaining 3 were missing the 67-kd component. Patients with chronic granulomatous disease whose functional defect was localized to the neutrophil membrane (classic X-linked cytochrome b-negative type and two other rare variants) had normal amounts of both cytosolic components. We estimate that approximately 33 percent of all patients with chronic granulomatous disease are missing the 47-kd cytosolic oxidase component and about 5 percent of patients are missing the 67-kd component. Chronic granulomatous disease caused by a defect in any cytosolic factors other than the 47-kd and 67-kd proteins, if it exists, is apparently rare.

Novel domains in NADPH oxidase subunits, sorting nexins, and PtdIns 3‐kinases: Binding partners of SH3 domains?

“…The most common cause of CCDs is an X-linked inheritance, resulting in the deficiency of the large /3 subunit of flavocytochrome b (gp91Ph0"). In approximately 3 U O % of cases, however, autosomally inherited deficiencies of other subunits with masses 47k and 67k (p47phox, and p67pho") lead to CCD (Clark et al, 1989;Let0 et al, 1990). Stimulation of neutrophils or other phagocytes results in these two cytosolic proteins, along with the small GTPases Racl or Rac2, translocating to the plasma membrane; subsequently, they form the functional NADPH oxidase, in complex with the transmembrane and heterodimeric gp9 Iphox-p22phox flavocytochrome b5S8.…”

Prolonged production of NADPH oxidase-corrected granulocytes after gene therapy of chronic granulomatous disease

“…When normal phagocytes engulf opsonized pathogens, the oxidase becomes activated by translocation of three cytoplasmic proteins (p47 phox , p67 phox , and rac-2) to the cell membrane where they bind to flavocytochrome b 558 (a heteromeric transmembrane protein composed of two peptides, gp91 phox and p22 phox ) (3,4). The genetic basis of CGD is heterogeneous (1,5). The most common form (about two-thirds of the cases) is X chromosomelinked, resulting from mutations in the gp91 phox gene.…”

NADPH:O2 oxidoreductase of human eosinophils in the cell‐free system

“…Phorbol myristic acetate (PMA) was from Consolidated Midland Corp., Katonah, NY, USA. Serum-treated zymosan was prepared as described before [12]. Reagents and molecular-weight markers for SDS-polyacrylamide gelelctrophoresis (SDS-PAAGE) were from BioRad Laboratories, Richmond, CA, USA.…”

“…Two cytosolic proteins have been characterized, a 47-kDa phosphoprotein [8,9,12] and a protein of 67 kDa [9,12], These proteins can be visualized by immunoblotting with a polyclonal rabbit antiserum B-l [l 11. Fig.…”