Familial aggregation of IgAD and autoimmunity.

ABSTRACT

BACKGROUND: The 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. OBJECTIVE: To evaluate the prevalence of autoimmunity among IgAD individuals and their 1 degrees relatives. MATERIAL AND METHODS: A total of 43 IgAD individuals (32 adults and 11 children) and all available 1 degrees 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. RESULTS: Eight 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 degrees relatives, 27/269 (10%) had autoimmunity, compared to an estimate of 5% in the general population (p<0.05). CONCLUSION: Autoimmune diseases are highly prevalent in individuals with IgAD and more common in their 1 degrees relatives than expected, thus, suggesting a possible common genetic component.