Mutation in BTK Gene Causing an Atypical Presentation of XLA

Patients with X-linked agammaglobulinemia (XLA) are susceptible to bacterial infections particularly due to encapsulated pyogenic bacteria, organisms for which opsonization by antibody is a primary host defense. Additionally, enteroviral encephalitis and chronic diarrhea due to Giardia are seen in XLA. However, fungal infections are rarely present. In this report, we describe the case of a 17 month-old boy with absent BTK protein expression caused by a novel de-novo variant of the BTK gene, who presented with neutropenic fever and sepsis caused by Candida and Pseudomonas aeruginosa