Autism spectrum disorders (ASD) often show obsessive repetitive symptoms that are characteristic to obsessive-compulsive disorder (OCD). Aberrant glutamate function has been suggested to a risk for both ASDs and OCD. Considering the common metabolic pathway and recent results from association studies both in OCD and ASDs, a question, whether there is common molecular background in ASDs and OCD, was raised.
Ten single nucleotide polymorphisms (SNPs) at 9p24 and 11p12-p13 containing glutamate transporter genes SLC1A1 and SLC1A2 and their neighboring regions in 175 patients with ASDs and 216 controls of Finnish origin were analyzed using real-time-PCR or direct sequencing.
The strongest association was detected with rs1340513 in the JMJD2C gene at 9p24.1 (P=0.007; corrected P=0.011) that is the same SNP associated with infantile autism (P=0.0007) in the autism genome project consortium (2007). No association was detected at 11p12-p13 with ASD. Interestingly, the strongest association in OCD has been found at rs301443 (P=0.000067) residing between SLC1A1 and JMJD2C at 9p24.
In summary, our results give evidence for a possible common locus for OCD and ASDs at 9p24. We speculate that the area may represent a special candidate region for obsessive repetitive symptoms in ASDs.