Type 2 hyper-IgM syndrome with a rare variant of AICDA gene mutation in a young woman

We report the case of a woman in her early 20s with a history of recurrent infection, atopic dermatitis, filariasis and bilateral purulent ear discharge since childhood with tonsillar enlargement on examination. She was started on supportive care and evaluated for primary immunodeficiency disease. Blood investigations revealed increased IgM levels with reduced IgG, IgA and IgE levels. Radiological imaging of the chest revealed bilateral bronchiectasis. Otoscopic examination showed features suggestive of chronic suppurative otitis media. Next-generation sequencing identified homozygous single base pair deletion in exon 2 of the activation-induced cytidine deaminase gene. Thus, a diagnosis of hyper-IgM syndrome type 2 was confirmed. The patient was started on monthly intravenous immunoglobulin replacement therapy and is currently symptomatically better, and she remains under regular follow-up.