IMMUNOGENETIC STUDIES IN AUTISM AND RELATED DISORDERS

The major histocompatibility complex comprises a number of genes that control the function and regulation of the immune system. One of these genes, the C4B gene, encodes a product that is involved in eliminatin g pathogens such as viruses and bacteria from the body. We previously reported that a deficient form of the C4B gene, termed the C4B null al lele (no C4B protein produced) had an increased frequency in autism. I n this study we attempted to confirm the increased incidence of the C4 B null allele in autism and investigated the presence of a C48 null al lele in two other childhood disorders, attention-deficit hyperactivity disorder and dyslexia (reading disability). In addition, we explored the relationship of autism to the DR beta 1 gene, a gene located close to the C4B in autism. We confirmed the finding of an increased freque ncy of the C4B null allele in autism and found that the related disord ers also had an increased frequency of this null allele. In addition, two alleles of the DR beta 1 gene also had significantly increased rep resentation in the autistic subjects.