Definition of Selective deficiency of IgA:

Selective deficiency of IgA is the most common immune deficiency disorder. Persons with this disorder have low or absent blood levels of a special protein called immunoglobulin A.

Causes, incidence, and risk factors:

IgA deficiency is inherited, which means it's passed down through families. It may be inherited as an autosomal dominant or autosomal recessive trait. It is found in approximately 1 in 700 individuals of European origin. It is less common in people of other ethnicities.

See also: Celiac disease - sprue