ENU-induced G to A transition at base pair 24,377,855 (v38) on chromosome 5, or base pair 13,037 in the GenBank genomic region NC_000071. The mutation corresponds to residue 1,998 in the mRNA sequence NM_008713 within exon 16 of 26 total exons. The mutation results in a cysteine to tyrosine substitution at position 660 (C660Y) in the NOS3 protein.