Which one of the immunodeficiency is caused by a mutation in BTK gene:
Which one of the immunodeficiency is caused by a mutation in BTK gene:
Select an option to attempt
Correct Answer: Option B
Explanation
BTK gene mutation and immunodeficiency:BTK (Bruton's Tyrosine Kinase) is a non-receptor tyrosine kinase essential for B cell development:• BTK is required for pro-B cell → pre-B cell transition in the bone marrow.• Mutations in BTK (X-linked gene) → B cell development arrests at the pro-B stage → virtually no mature B cells in periphery → absence of all immunoglobulins (agammaglobulinemia).Disease: X-linked agammaglobulinemia (XLA), also called Bruton's disease:• X-linked recessive (gene on X chromosome, males affected)• Presents in early childhood with recurrent bacterial infections• Treatment: regular intravenous immunoglobulin (IVIG) infusionsDistractors:• X-linked SCID: caused by mutations in the IL-2 receptor gamma chain (IL2RG), affecting both T and NK cells.• DiGeorge syndrome: 22q11.2 deletion, thymus aplasia → T cell deficiency.• Chronic granulomatous disease: mutations in NADPH oxidase genes (phagocyte killing defect).Answer: X-linked agammaglobulinemia (Option 2).