Autism and Shared Parental HLA Antigens

Abstract

We hypothesized that parents of autistic children may share HLA antigens (human leukocyte antigens or histocompatibility antigens) more commonly than the population of parents of normal children since autism is present at birth or shortly thereafter, and since mothers of autistic children tend to share some of the symptoms of preeclampsia and parents of autistic children are reported to have an increased incidence of spontaneous abortions. Heterozygosity (differences at the HLA sites between parents) is apparently important to enhance the protection of the fetus from the mother's immune system. We studied the HLA antigens of 52 sets of parents of autistic children and compared them with the HLA antigens of 83 sets of parents of normal children reported in the literature. We found 39 out of 52 (75%) of the experimental group shared at least one antigen. The comparison group shared 18 out of 83 (22%). This difference was significant at the less than 0.0001 level of confidence (χ2=35.096). We recommend further research in this potentially fruitful area.