ENU-induced T to A transversion at base pair 66,452,250 (v38) on chromosome 5, or base pair 166,568 in the GenBank genomic region NC_000071 encoding Apbb2. The mutation corresponds to residue 624 in the mRNA sequence NM_001201415 within exon 5 of 16 total exons. The mutation results in a methionine (M) to lysine (K) substitution at position 18 (M18K) in the APBB2 protein.