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.
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.
Noack
D
D
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
Rae
J
J
Cross
A R
AR
Ellis
B A
BA
Newburger
P E
PE
Curnutte
J T
JT
Heyworth
P G
PG
D000293:Adolescent; D000328:Adult; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005091:Exons; D005192:Family Health; D005260:Female; D005838:Genotype; D006105:Granulomatous Disease, Chronic / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D019255:NADPH Oxidases; D010750:Phosphoproteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011544:Pseudogenes
D010750:Phosphoproteins; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1