ENU-induced C to T transition at base pair 171,158,810 (v38) on chromosome 1, or base pair 8,098 in the GenBank genomic region NC_000067 encoding Mpz. The mutation corresponds to residue 458 in the NM_008623 mRNA sequence in exon 5 of 8 total exons. The mutation results in an arginine (R) to cysteine (C) substitution at position 98 (R98C) in both variants of the MPZ protein. (J:265100)