Using CRISPR/Cas9 technology, an 8 bp deletion (ACACAAGT) was created in the FVB strain, resulting in a frameshift and a premature stop codon. The resulting peptide lacks the last 21 wild-type amino-acids and gains five new amino-acids before premature termination, thus disrupting both an ER retention signal and an RGS3 PDZ binding motif. The deletion encompasses SNP rs13477613 (G>T, the last T in the deletion), which is specific to FVB and A/J.