A single nucleotide point mutation (C>T) in exon 12 at position 2548 of the cDNA changes glutamine codon 764 CAA to premature stop codon TAA which is predicted to generate a truncated protein of 763 amino acids. This T version of the allele is only found in B6 and BTBR T+ Itprtf/J (Jax strain: 002282) strains. This allele is wild-type (C version, coding) in 20 non-B6 strains. (J:81437, J:245487)