Prevalence of autism spectrum disorders in relatives of patients with selective immunoglobulin A deficiency.

BACKGROUND An association of selective IgA (immunoglobulin A) deficiency in individuals with autism has been previously described. The objective of this study was to examine the incidence of autism spectrum disorders (ASD) in children and siblings of selective IgA deficient patients. OBJECTIVE to assess the likelihood of parents with the most common type of primary immunodeficiency (selective IgA deficiency) having children with ASD and to investigate the occurrence of ASD in siblings of the immunodeficient patients. METHODS A study was conducted in 31 selective IgA deficient patients and 62 age and gender-matched controls. Children and siblings of IgA deficient patients and controls were screened for an ASD (autism spectrum disorder) using a standard questionnaire. RESULTS Only one patient in the IgA deficient group had classical autism. Three children in that group (10.3%) had an ASD compared to only one in the control group (1.6%) and this difference was statistically significant. In terms of siblings, there was a higher occurrence of an ASD in the IgA deficient group than in the control group, but the difference was not statistically significant. A high incidence of allergies (71%) was documented in IgA deficient patients. All individuals with allergies had food sensitivities. There was a predominance of the male gender in cases identified with an ASD in all groups. CONCLUSIONS A lower prevalence of ASD was observed in the IgA deficient group, as compared to other reports. The study suggests that screening for an ASD seems appropriate for children of IgA deficient patients.