Chronic granulomatous disease caused by mutations other than the common GT deletion inNCF1, the gene encoding the p47^phoxcomponent of the phagocyte NADPH oxidase

Abstract

Chronic granulomatous disease (CGD) is an inherited immunodeficiency caused by defects in any of four genes encoding components of the leukocyte nicotinamide dinucleotide phosphate, reduced (NADPH) oxidase. One of these is the autosomal neutrophil cytosolic factor 1 (NCF1) gene encoding the p47phox protein. Most (>97%) CGD patients without p47phox (A47 degrees CGD) are homozygotes for one particular mutation in NCF1, a GT deletion in exon 2. This is due to recombination events between NCF1 and its two pseudogenes (psiNCF1) that contain this GT deletion. We have previously set up a gene-scan method to establish the ratio of NCF1 genes and pseudogenes. With this method we now found, in three CGD families patients with the normal number of two intact NCF1 genes (and four psiNCF1 genes) and in six CGD families, patients with one intact NCF1 gene (and five psiNCF1 genes). All patients lacked p47phox protein expression. These results indicate that other mutations were present in their NCF1 gene than the GT deletion. To identify these mutations, we designed PCR primers to specifically amplify the cDNA or parts of the genomic DNA from NCF1 but not from the psiNCF1 genes. We found point mutations in NCF1 in eight families. In another family, we found a 2,860-bp deletion starting in intron 2 and ending in intron 5. In six families the patients were compound heterozygotes for the GT deletion and one of these other mutations; in two families the patients had a homozygous missense mutation; and in one family the patient was a compound heterozygote for a splice defect and a nonsense mutation. Family members with either the GT deletion or one of these other mutations were identified as carriers. This knowledge was used in one of the families for prenatal diagnosis.

A novel mutation in NCF1 in an adult CGD patient with a liver abscess as first presentation

“…Only 15 other mutations affecting NCF1 have been reported (five affecting splicing and ten affecting the amino-acid sequence directly). 8 Our patient was found to be compound heterozygous for the 75_76delGT mutation and a novel mutation, c.837delC, which to our knowledge has not been reported before. Figure 2 (a) Western blot with the A-7 antibody directed against p47 phox revealed that the protein was absent in the patient (P), and present in the mother (M), the father (F) and a healthy control (C).…”

“…9 In the literature, only three p47 phox -deficient patients have been reported who were diagnosed with CGD in their third decade of life. These were a 21-year old male with infections starting early in life that were not typical for CGD, thus postponing the correct diagnosis, a 22-year old female with infections starting early in life that were typical of CGD, 8 and a 20-year old male with unspecified infections. 10 Thus, the p47 phoxdeficient patient we describe here has the highest age at diagnosis reported thus far.…”

Molecular characterization and tissue transcription profile analyses of three novel pig genes - NDP, CLN3 and NCF1

“…Zhong et al (1998) had reported that a missense mutation of glutamic acid (E) to lysine (K) at position 295 in the human CLN3 protein has been implicated in Juvenile neuronal ceroid lipofuscinosis (Batten disease). One particular mutation in NCF1, a GT deletion in exon 2 had been identifi ed to be associated with >97% cases of human chronic granulomatous disease (Roos et al, 2006). Therefore, isolation of the encoding regions of the porcine NDP, CLN3 and NCF1 genes is utmost important to detect these three kinds of diseases.…”

“…This oxidase is a multicomponent enzyme that is activated to produce superoxide anion. Mutations in this gene have been identifi ed to be associated with chronic granulomatous disease (El Kares et al, 2006;Roos et al, 2006;Köker et al, 2007).…”

Focus on immunogenetics: diagnosis, molecular genetics, mutations, and diseases

“…The research article by Roos et al [2006] indicates that in addition to highly common mutations, other defects also lead to disease. They investigated NCF1, which encodes the p47 phox protein functional in leukocyte NADPH oxidase.…”