A Novel IL17RA Mutation In A Male Child With Chronic Mucocutaneous Candidiasis

Abstract Purpose: Chronic mucocutaneous candidiasis (CMC) is characterized by persistent or recurrent fungal infections involving the nails, skin, oral and genital mucosa. Impaired IL17 mediated immunity is a cause for CMC. Patient and Methods: After the next-generation sequencing analysis showed the IL17RA variant, confirmation by Sanger sequencing was done. Functional validation of the variant by flow cytometry was performed. Results: We present a 6-year-old male patient who presented with recurrent oral and genital candida infections and eczema. He had staphylococcal skin lesions in addition to the fungal susceptibility and eczema. The patient was found to carry a previously unreported homozygous nonsense [(c.787C> T) (p.Arg263Ter)] mutation in the IL17RA gene. Sanger sequencing confirmed the variant and showed the segregation of the variant in the family. We used flow cytometry to detect IL17RA protein expression in patients’ PBMCs and measured the Th17 cell percentages. Severely decreased IL17RA protein expression was observed in patient’s PBMCs and decreased CD4+ IL17+ cell percentage as well as decreased IL17F expression in CD4+ cells compared with healthy control. Conclusion: In patients with chronic recurrent fungal and bacterial and/or infections of the skin, mucosa, and nails, advanced immunological studies should be performed to document the genetic susceptibility even if basic immunological tests are normal.