T to C transition at base pair 60,778,032 (v38) on chromosome 11, or base pair 508 in the GenBank genomic region NC_000077 encoding Smcr8. The mutation corresponds to residue 508 (c.508T>C) in the mRNA sequence NM_001085440.1 within exon 1 of 2 total exons. The mutation results in an isoleucine (I) to threonine (T) substitution at position 2 (I2T) in the SMCR8 protein (p.I2T).