Although dozens of genes have been linked to psychiatric disorders, connecting the dots between behavioral phenotypes and genetic variations has not been easy. In this issue of the Archives, 2 groups of investigators report that statistically significant associations between the transmission of obsessive-compulsive disorder (OCD) for male but not female offspring, and a genetic locus on chromosome 9p24 that codes for a high-affinity neuronal/epithelial excitatory amino acid transporter (ECCA-1) known in the genetic world as SLC1A1 (solute carrier family 1, member 1; Online Mendelian Inheritance in Man [OMIM] 133550).1,2 In the brain, this transporter is crucial in terminating the action of the excitatory neurotransmitter glutamate and in maintaining extracellular glutamate concentrations within a normal range.