Variation in GRIN2B contributes to weak performance in verbal short-term memory in children with dyslexia

A multi-marker haplotype within GRIN2B, a gene coding for a subunit of the ionotropic glutamate receptor, has recently been found to be associated with variation in human memory performance [de Quervain and Papassotiropoulos, 2006]. The gene locus is located within a region that has been linked to a phonological memory phenotype in a recent genome scan in families with dyslexia [Brkanac et al., 2008]. These findings may indicate the involvement of GRIN2B in memory-related aspects of human cognition. Memory performance is one of the cognitive functions observed to be disordered in dyslexia patients. We therefore investigated whether genetic variation in GRIN2B contributes to specific quantitative measures in a German dyslexia sample by genotyping 66 SNPs in its entire genomic region. We found supportive evidence that markers in intron 3 are associated with short-term memory in dyslexia, and were able to demonstrate that this effect is even stronger when only maternal transmission is considered. These results suggest that variation within GRIN2B may contribute to the genetic background of specific cognitive processes which are correlates of the dyslexia phenotype.