Out of the disorders where we can calculate prevalence, the lowest prevalence (6%) occurs in GRIN2A-related disorders, which disrupt the N-methyl-D-aspartate (NMDA) receptor, critical for learning and memory (http://www.ncbi.nlm.nih.gov/gene/2903), resulting in epilepsy-aphasia spectrum. This evidence concerns the gene GRIN2A and Aphasia.