This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. The molecular lesion is an A to G substitution at coding nucleotide 521 in exon 4 of the cDNA (c.521A>G, NM_001163144). This changes the aspartic acid residue to glycine at position 174 of the encoded protein (p.D174G). (J:175213) Additional incidental mutations were detected in sequencing for the causative mutation, Pcsk5b2b585Clo, and may be present in stocks carrying this mutation.