Consanguinity in primary immunodeficiency disorders; the report from Iranian Primary Immunodeficiency Registry.

PROBLEM Primary Immunodeficiency Disorders (PiD) are a heterogeneous group of genetic disorders, with different modes of inheritance. This study was accomplished in order to determine the frequency of consanguineous marriages in the families of patients with PiD. METHOD In this study, the records 515 Iranian PiD patients were reviewed during a 25-year period. RESULTS The mean proportion of consanguineous marriages was 65.6% among PiD patients, while the overall rate was 38.6% in the country. The rate of consanguinity was 77.8% in cellular immunodeficiencies, 75.8% in combined immunodeficiencies, 72.5% in defects of phagocytic function, 58.6% in other immunodefiiencies, 54.1% in predominantly antibody deficiencies, and 50% in complement deficiencies. Moreover all patients with immunodeficiency associated with other diseases had consanguineous parents. Such marriages were most common in the parents of patients with Chediak-Higashi syndrome, severe combined immunodeficiencies, primary CD4 deficiency, ataxia-telangiectasia, selective IgG class deficiencies, chronic granulomatous disease, and Schwachman syndrome. CONCLUSIONS It is important to inform the general population about the dangers of consanguinity, which is very common in some areas such as Iran. Premarital examination to avoid genetic diseases could be suggested, especially in a community where the rate of consanguineous marriage is high.