Detection of NCF-2 Gene Expression in Egyptian Children with Chronic Granulomatous Disease

Abstract

Abstract Background Chronic granulomatous disease (CGD) is a rare inherited primary immunodeficiency disorder (PID) which is characterized by enhanced susceptibility to severe bacterial and fungal infections. It results from defects in one of the five polypeptide subunits of the nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) complex; CYBB (gp91-phox), NCF-1 (p47phox), CYBA (p22-phox), NCF-2 (p67-phox), or NCF-4 (p40-phox) with a resulting failure of the phagocytes in generating a variety of microbicidal reactive oxygen radicals during respiratory burst. Objectives This work intended to diagnose autosomal recessive (AR)-type of CGD by detection of NCF-2 gene expression using real time RT-PCR as a cheaper diagnostic method for CGD subtypes categorization among CGD children. Subjects and methods This case-control study was conducted on 15 children provisionally diagnosed as CGD patients by the use of dihydrorhodamine (DHR) stimulation index (Group I) in addition to 12 mothers and 8 fathers of the studied patients (Group IIa and IIb respectively) to detect the genetic mutations in carriers, if any, and 14 apparently healthy children as a control group (Group III). In the present study, cases with a fold change of NCF-2 gene expression less than 0.67 were considered defective for NCF-2 gene expression. At this cut-off value, from our molecularly studied subjects, 2 CGD cases and one mother showed underexpression of NCF-2 gene. In conclusion, defect in the NCF-2 gene, which encodes gp67-phox of the oxidase enzyme could be done by RT-PCR as a cheaper diagnostic method for CGD without the need to use complex and expensive methodologies such as northern blot, or genomic DNA sequencing.