The human δ2 glutamate receptor gene is not mutated in patients with spinocerebellar ataxia

The human glutamate receptor delta 2 gene (GRID2) shares 90% homology with the orthologous mouse gene. The mouse Grid2 gene is involved with functions of the cerebellum and spontaneous mutation of Grid2 leads to a spinocerebellar ataxia-like phenotype. To investigate whether such mutations occur in humans, we screened for mutations in the coding sequence of GRID2 in 24 patients with familial or sporadic spinocerebellar ataxia and in 52 normal controls. We detected no point mutations or insertion/deletion mutations in the 16 exons of GRID2. However, a polymorphic 4 nucleotide deletion (IVS5-121_-118 GAGT) and two single nucleotide polymorphisms (c.1251G>T and IVS14-63C>G) were identified. The frequency of these polymorphisms was similar between spinocerebellar ataxia patients and normal controls. These data indicate that spontaneous mutations do not occur in GRID2 and that the incidence of spinocerebellar ataxia in humans is not associated with GRID2 mutation or polymorphisms.