A 7-month-old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. Based on this family's history and clinical presentation, a mutation in which of the following genes is most likely to be found in this patient?

Question

Quizplus · Accepted Answer

X-linked severe combined immunodeficiency disease (SCID) results from mutations in the gene encoding the cytokine receptor common ƴ chain. Mutations in any of the other genes listed (JAK3 kinase, adenosine deaminase, RAG2, or purine nucleoside phosphorylase) cause severe combined immunodeficiency syndrome with autosomal recessive patterns of inheritance.

A 7-Month-Old Boy Is Evaluated in the Clinic for Recurrent