ENU-induced A to T transversion at base pair 80,260,724 (v38) on chromosome 10, or base pair 303 in the GenBank genomic region NC_000076 encoding Gamt. The mutation corresponds to residue 289 in the mRNA sequence NM_010255 within exon 1 of 6 total exons. The mutation results in substitution of arginine 60 to a premature stop codon (R60*) in the GAMT protein. (J:267482)