This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. The molecular lesion is a T to A substitution at coding nucleotide 3264 in exon 22 of the cDNA (c.3264T>A, NM_144788). This changes the tyrosine residue to a translation stop at position 1088 of the encoded protein (p.Y1088*). Additional incidental mutations were detected in sequencing for the causative mutation, Hectd1b2b327Clo, and may be present in stocks carrying this mutation.