PRIMARY IMMUNE DEFICIENCY DISEASES

Question 1

failure of T cell and B cell maturation; mutation in the common gamma chain of a cytokine receptor, leading to failure of IL-7 signaling and defective lymphopoiesis

Answer 1

X-SCID

Question 2

failure of T cell development; secondary defect in antibody responses; approx 50% of cases caused by mutation in the gene encoding ADA, leading to accumulation of toxic metabolites during lymphocyte maturation and proliferation

Answer 2

autosomal recessive SCID

Question 3

failure of B-cell maturation, absence of antibodies; caused by mutations in the BTK gene, which encodes B-cell tyrosine kinase, required for maturation signals from the pre-B cell and B cell receptors

Answer 3

X-linked agammaglobulinemia (XLA)

Question 4

failure of development of thymus, with T cell deficiency

Answer 4

Di George syndrome

Question 5

failure to produce isotope switched high affinity antibodies (IgG, IgA, IgE); mutations in genes encoding CD40L or activation-induced cytosine deaminase

Answer 5

X-linked hyper-IgM syndrome

Question 6

defects in antibody production; cause unknown in most cases

Answer 6

common variable immunodeficiency

Question 7

failure of IgA production; cause unknown

Answer 7

selective IgA deficiency