Prevalence of BTK mutations in male Algerian patterns with agammaglobulinemia and severe B cell lymphopenia

- XLA is the first described primary immunodeficiency and the most common form of agammaglobulinemia.
- It is characterized by susceptibility to recurrent infections, profound decrease of all immunoglobulin isotypes and very low level of B.
- The disorder is caused by mutations in the Bruton's Tyrosine Kinase (BTK)
- The XLA diagnosis was confirmed for six patients with different mutations. We identified a novel mutation (c.1522G > A) and five known mutations.
- One third of 9 unrelated Algerian male patients do not have mutations in BTK and thus likely suffer from autosomal recessive agammaglobulinemia.

X linked agammaglobulinemia (XLA) is the first described primary immunodeficiency and the most common form of agammaglobulinemia. It is characterized by susceptibility to recurrent infections, profound decrease of all immunoglobulin isotypes and very low level of B lymphocytes in peripheral blood. The disorder is caused by mutations in the Bruton's Tyrosine Kinase (BTK). Nine male patients suspected to have XLA from nine unrelated families were enrolled in this study. We performed sequencing of the BTK gene in all nine patients, and in the patients' relatives when possible. The XLA diagnosis was confirmed for six patients with six different mutations; we identified a novel mutation (c.1522G > A) and five known mutations. One third of nine unrelated patients do not have mutations in BTK and thus likely suffer from autosomal recessive agammaglobulinemia in the setting of consanguinity. Our results support that the autosomal recessive agammaglobulinemia can be more common in Algeria.