ENU-induced A to T transversion at base pair 94,528,257 (v38) on chromosome 13, or base pair 169,678 in the GenBank genomic region NC_000079 encoding Ap3b1. The mutation corresponds to residue 2,847 in the mRNA sequence NM_009680 within exon 23 of 27 total exons. The mutation results in an arginine to serine substitution at position 901 (R901S) in the AP3B1 protein.