ENU-induced A to G transition at base pair 142,456,333 (v38) on chromosome 6, or base pair 16,798 in the GenBank genomic region NC_000072 encoding Gys2. The mutation corresponds to residue 1,087 in the mRNA sequence NM_145572 within exon 5 of 17 total exons. The mutation results in a glutamic acid (E) to glycine (G) substitution at position 260 (E260G) in the GYS2 protein.