Familial aggregation of IgAD and autoimmunity

BackgroundThe prevalence of autoimmunity is thought to be increased among IgA deficient (IgAD) individuals. However, it is currently unclear if the two conditions coincide within families.ObjectiveTo evaluate the prevalence of autoimmunity among IgAD individuals and their 1° relatives.Material and methodsA total of 43 IgAD individuals (32 adults and 11 children) and all available 1° relatives were evaluated by a physician. A family history of autoimmunity was obtained, together with physical examination and a structured questionnaire that focused on symptoms and signs suggestive of autoimmunity.ResultsEight of the 32 (25%) adult IgAD, were found to have definite autoimmunity, with organ specific- and systemic autoimmune diseases equally distributed. None of the IgAD children had autoimmunity. Among the 1° relatives, 27/269 (10%) had autoimmunity, compared to an estimate of 5% in the general population (p < 0.05).ConclusionAutoimmune diseases are highly prevalent in individuals with IgAD and more common in their 1° relatives than expected, thus, suggesting a possible common genetic component.