This mutation was discovered in a TLR Signaling Screen of G3 progeny of an ENU mutagenized male mouse. The mutation comprises a T to A transversion at nucleotide position 1301 of the gene (Genbank: NM_011604) that results in conversion of a triplet encoding leucine at amino acid position 190 to a termination codon (L190Ter), truncating the protein by 416 amino acids at its C terminus.