NPGRJ_ng_1577 625..629

Imprinted genes show differential expression between maternal and paternal alleles as a consequence of epigenetic modification that can result in ‘parent-of-origin’ effects on phenotypic traits1. There is increasing evidence from mouse and human studies that imprinted genes may influence behavior and cognitive functioning2. Previous work in girls with Turner syndrome (45,XO) has suggested that there are X-linked parent-of-origin effects on brain development3 and cognitive functioning4, although the interpretation of these data in terms of imprinted gene effects has been questioned5. We used a 39,XO mouse model to examine the influence of the parental origin of the X chromosome on cognitive behaviors and expression of X-linked genes in brain. Our findings confirm the existence of X-linked imprinted effects on cognitive processes and identify a new maternally expressed imprinted gene candidate on the X chromosome, Xlr3b, which may be of importance in mediating the behavioral effects.