This mutation was discovered by its visible phenotype among G1 progeny of an ENU mutagenized mouse. It comprises an A to T transversion at nucleotide position 1178, in the tenth of the gene's 11 exons, that replaces a triplet encoding lysine with a premature transcription termination codon at amino acid position 366 (K366Ter) and truncates the protein by 98 amino acids at its carboxyl terminus. (J:146738)