This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. It is a subline of b2b227Clo. The molecular lesion is a T to A substitution at coding nucleotide 2978 in exon 20 of the cDNA (c.2978T>A, NM_001081393). This changes the methionine residue to lysine at position 993 of the encoded protein (p.M993K). (J:175213) Additional incidental mutations were detected in sequencing for the causative mutation, Odad2b2b227.1Clo, and may be present in stocks carrying this mutation.