This mutation comprises a transversion mutation altering coding nucleotide 124 from a G to a C (c.124G>C), which results in a glycine to arginine substitution at position 42 of the protein (p.G42R). This position corresponds to the ninth amino acid of the paired domain. Northern blot analysis on RNA derived from homozygous mice demonstrated that mRNA levels were approximately 5 fold lower than wild-type.