Novel Diagnostic Tool for p47phox-Deficient Chronic Granulomatous Disease Patient and Carrier Detection

Abstract

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by mutations of the phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Autosomal recessive p47phox-deficient CGD (p47phox CGD) is the second most frequent form of the disease in western countries, and more than 94% of patients have a disease-causing dinucleotide deletion (ΔGT) in the neutrophil cytosolic factor 1 (NCF1) gene. The ΔGT mutation is most likely transferred onto the NCF1 from one of its two pseudogenes co-localized on the same chromosome. The presence of NCF1 pseudogenes in healthy individuals makes the genetic diagnostics of ΔGT p47phox CGD challenging, as it requires the distinction between ΔGT in NCF1 and in the two pseudogenes. We have developed a diagnostic tool for the identification of p47phox CGD based on PCR co-amplification of NCF1 and its pseudogenes, followed by band intensity quantification of restriction fragment length polymorphism products. The single-day, reliable p47phox CGD diagnostics allow for robust discrimination of homozygous ΔGT p47phox CGD patients from heterozygous carriers and healthy individuals, as well as for monitoring gene therapy efficacy.