Novel BTK mutation in X-linked agammaglobulinemia: Report of a 17-year-old male.

Abstract

X-linked agammaglobulinemia (XLA), the first known primary immunodeficiency, is caused by rare mutations in Bruton's tyrosine kinase (BTK) gene. Mutations in the BTK gene lead to a failure in the development and maturation of B-cell linage. A decreased number of B-cells results in agammaglobulinemia and increased susceptibility to a variety of infections. Therefore, patients with XLA usually manifest with repetitive bacterial infections, such as upper respiratory tract infections, septic arthritis, osteomyelitis, and urinary tract infections, since their infancy. We report a 17-year-old Iranian boy with XLA, referred to us with a history of severe and recurrent episodes of bacterial infections for a period of six years. Genetic analysis using the whole Exome sequencing revealed a hemizygous missense mutation in the BTK gene (c.428 A > T, p.His143Leu). To our knowledge, c.428 A > T has not been reported in the BTK gene.