Objectives: To test the hypothesis of association between the APOE gene variants (E2, E3, E4) and autism disorder in a cohort of Puerto Rican children.
Methods: A case-control study was performed with 50 patients, aged 3-12 y.o, diagnosed with Autism and 55 unrelated age-matched control subjects. Genomic material was collected from buccal swabs. The amplification of the APOE gene was carried out by PCR and the polymorphic variants were identified by restriction fragment length polymorphism and agarose gel electrophoresis.
Results: We found no significant difference in allele frequency between autistic (4% E2, 91% E3, 5% E4) and control (4% E2, 85% E3, 11% E4) children (Χ2 = 3.69, df =2, P = 0.15). However, we did find a significant difference for genotype frequency with autistic children (8% E2/E3, 86% E3/E3, 6% E3/E4) showing a lower frequency of the E3/E4 genotype than controls (7% E2/E3, 71% E3/E3, 22% E3/E4); (Χ2= 17.5, df = 2, P = 0.0002).
Conclusions: The results of the present study support the hypothesis of association between genotype, based on the APOE variants, and autism in our cohort of Puerto Rican children. In particular, significant underrepresentation of the E3/E4 genotype was observed in group of autistic subjects, supporting the possible involvement of apolipoprotein in the development of autism.