Novel CYBA mutation in a family with BCGitis

Chronic granulomatous disease is a non-prevalent genetic disorder due to different structural gene mutations encoding components of nicotinamide adenine dinucleotide phosphate oxidase complex. Nicotinamide adenine dinucleotide phosphate oxidase is a complex made by a group of five proteins (subunit) and plays an important role in the innate immune system. Five structural genes are responsible for encoding each subunit, in which cytochrome b-245 alpha chain (also known as p22-phox) is encoded by CYBA gene. CYBA gene mutation leads to a group of autosomal dominant chronic granulomatous disease. Decreased level or lack of nicotinamide adenine dinucleotide phosphate oxidase leaves affected individuals vulnerable to many types of infections and excessive inflammation. In this study, a family affected by BCGitis caused by a novel intronic autosomal recessive CYBA mutation (88,713,158 C > T) has been described. The proband is a 5-year-old girl with chronic granulomatous disease who was referred to the clinic due to BCGitis. The culprit mutation was detected following whole genome sequencing and was confirmed among the family members by Sanger sequencing. Being symptom-free at the time of diagnosis, despite the proband's mother homozygosity, was a characteristic feature of this report. Remarkably, none of the CYBA-mutated members, as a known chronic granulomatous disease causing gene, has expressed symptoms other than regional lymph node enlargements. This might explain the gene mutation site importance in demonstrating different manifestations.