The three CYBA variants (rs4673, rs1049254 and rs1049255) are benign: new evidence from a patient with CGD

Background: Chronic granulomatous disease (CGD) is an inherited immunodeficiency disease caused by the defect of NADPH oxidase. Mutations in CYBB or CYBA gene may result in membrane subunits, gp91phox or p22phox, expression failure respectively and NADPH oxidase deficiency. Previous study showed that three variants, c.214 T > C (rs4673), c.521 T > C (rs1049254) and c.*24G > A (rs1049255), in CYBA gene form a haplotype, which are associated with decreased reactive oxygen species generation. The study aims to confirm the three above mentioned variants are benign and report a novel mutation in CYBB gene. Methods: A patient with CGD and his family members were enrolled in the study. NADPH oxidase activity and gp91phox protein expression of neutrophils were analyzed by flow cytometry. Direct sequencing was used to detect CYBB and CYBA gene mutations. Results: The patient was diagnosed with CGD according to clinical and immune phenotype. The case has a novel homozygous mutation in CYBB gene and the above mentioned three variants in CYBA gene. The mutation in CYBB gene was confirmed to be pathogenic, and the three variants in CYBA gene to be benign. Conclusions: The study not only reported a novel mutation in CYBB, which results in CGD, but also confirmed the above mentioned three variants in CYBA are benign.