Non-classical human leukocyte antigen class I in Tunisian children with autism

Autism spectrum disorders (ASD) are one of the most common childhood morbidities characterized by deficits in communication and social skills. Increasing evidence has suggested associations between immune genes located in the human leukocyte antigen (HLA) complex and etiology of autism.

In this study, we investigated whether the non-classical class I HLA-G, -E, and -F polymorphisms are associated with genetic predisposition to autism in Tunisia. We aimed to find a correlation between HLA-G genotypes and soluble HLA-G (sHLA-G) levels. We have analyzed the HLA-G, -E, and -F genotypes of 15 autistic children and their parents. DNA typing of HLA class I genes was performed using PCR-SSP and PCR-RFLP methods. Also, we evaluated the serum levels of HLA-G (1 and 5) by a validated ELISA technique in autistic probands and their parents.

No association was found between any polymorphism and autism in the study subjects. Additionally, we found no correlation between sHLA-G1 and sHLA-G5 and autism. Also, no significant difference in sHLA-G testing in parents and offspring was found. However, parents carrying [GG] genotype presented a higher sHLA-G levels than those carrying ([CC]+[GC]) genotypes (p = 0.037).

From this preliminary study, we conclude that the investigated polymorphisms of HLA-G, -E, and -F genes did not lead to autism susceptibility in Tunisian children. However, the CGTIGA haplotype was found to be associated with the disease.