This allele was identified by screening a bank of cryopreserved sperm and genomic DNA of G1 male progeny from an ENU Mutagenesis project (http://www.brc.riken.jp/lab/gsc/mouse/). A T to A transversion en exon 7 results in replacement of Aspartic Acid at codon 336 with Glutamic Acid. (J:197674)