This mutation was discovered in a TLR Signaling Screen of G3 progeny of an ENU mutagenized male mouse. The mutation comprises an A to T transversion at nucleotide position 1501 of the gene (Genbank: NM_011604) that results in conversion of a triplet encoding arginine at amino acid position 457 to a termination codon (R457Ter), truncating the protein by 349 amino acids at its C terminus.