This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. The molecular lesion is a T to C substitution at nucleotide +2 following coding nucleotide 828 (c.828+2T>C, NM_029939) in intron 6. This changes splice donor site G-GT to G-GC (which is assumed to be less efficient) (J:175213) Additional incidental mutations were detected in sequencing for the causative mutation, Odad3b2b1885Clo, and may be present in stocks carrying this mutation.