ENU-induced T to C transition at base pair 78,491,848 (v38) on chromosome 15, or base pair 19,774 in the GenBank genomic region NC_000081 encoding Il2rb. The mutation corresponds to residue 151 in the mRNA sequence NM_008368 within exon 2 of 10 total exons. The mutation results in a methionine to threonine substitution at position 1 (M1T) in the IL2RB protein.