IgA deficiency

Clinical Presentation: Anaphylaxis following blood transfusion

Selective IgA deficiency (Page 112) 
Defect: Unknown. Most common 1° immunodeficiency. 
Presentation: Majority Asymptomatic. Can see Airway and GI infections, Autoimmune disease, Atopy, Anaphylaxis to IgA-containing products.
Findings: Decreased IgA with normal IgG, IgM levels. Increased susceptibility to giardiasis.

 Ataxia-telangiectasia (Page 113) 
Defect: Defects in ATM gene lead to failure to repair DNA double strand breaks leads to cell cycle arrest. 
Presentation: Triad - cerebellar defects (Ataxia), spider Angiomas (telangiectasia A ), IgA deficiency.