Rare de novo deletion of metabotropic glutamate receptor 7 (GRM7) gene in a patient with autism spectrum disorder.

GRM7, the gene encoding metabotropic glutamate receptor 7 (mGluR7), have been implicated in multiple neuropsychiatric disorders and shown to mediate excitatory synaptic neurotransmitter signaling and plasticity in the mammalian brain. Here we report a 303 kb de novo deletion at band 3p26.1, disrupting five coding exons of GRM7 in a proband with autism spectrum disorder, and hyperactivity. Our exon transcriptome-mutation contingency index method shows that three of the exons within the breakpoint boundaries are under purifying selection and highly expressed in prenatal brain regions. Based on our results and a thorough review of the literature, we propose that haploinsufficiency of the GRM7 product (mGluR7) contributes to autism spectrum disorders and hyperactivity phenotype as seen in the patient described here.