Autosomal recessive chronic granulomatous disease caused by defects in NCF-1, the gene encoding the phagocyte p47-phox: mutations not arising in the NCF-1 pseudogenes
Department of Pediatrics
Medical Subject Headings
Adolescent; Adult; Alleles; Child; Child, Preschool; DNA Mutational Analysis; Exons; Family Health; Female; Genotype; Granulomatous Disease, Chronic; Humans; Male; *Mutation; NADPH Oxidase; Phosphoproteins; Polymerase Chain Reaction; Pseudogenes
Hematology | Oncology | Pediatrics
Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in any one of 4 genes encoding phagocyte NADPH oxidase subunits. Unlike other CGD subtypes, in which there is great heterogeneity among mutations, 97% of affected alleles in patients previously reported with A47(0) CGD carry a single mutation, a GT deletion (DeltaGT) in exon 2 of the p47-phox gene, NCF-1. This unusually high incidence results from recombination events between NCF-1 and its highly homologous pseudogenes, in which DeltaGT originates. In 50 consecutive patients with A47(0) CGD, 4 were identified who were heterozygous for DeltaGT in NCF-1, and for the first time, 2 were identified whose DNA appeared normal at this position. To avoid co-amplification of pseudogene sequence and to enable the identification of mutations in these patients, allele-specific polymerase chain reaction was used to amplify alleles not containing DeltaGT. In each of the 4 patients who were heterozygous for DeltaGT, an additional novel mutation was identified. These were 2 missense mutations, G125 --> A in exon 2 (predicting Arg42 --> Gln) and G784 --> A in exon 8 (Gly262 --> Ser), and 2 splice junction mutations at the 5' end of intron 1, gt --> at and gtg --> gtt. The first of 2 patients who appeared normal at the GT position was a compound heterozygote with the G125 --> A transition on one allele and a deletion of G811 on the other. In the second of these patients, only a single defect was detected, G574 --> A, which predicts Gly192 --> Ser but is likely to result in defective splicing because it represents the final nucleotide of exon 6.
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Citation: Blood. 2001 Jan 1;97(1):305-11. doi 10.1182/blood.V97.1.305
Noack, D.; Rae, J.; Cross, Andrew R.; Ellis, Beverly A.; Newburger, Peter E.; Curnutte, John T.; and Heyworth, Paul G., "Autosomal recessive chronic granulomatous disease caused by defects in NCF-1, the gene encoding the phagocyte p47-phox: mutations not arising in the NCF-1 pseudogenes" (2001). Hematology/Oncology. 34.