This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. The molecular lesion is a T to A substitution at nucleotide +2 after coding nucleotide 2426 (c.2426+2T>A, NM_008306) in intron 12. This changes splice donor site C-GT to C-GA (which is assumed to be inactive). (J:175213) Additional incidental mutations were detected in sequencing for the causative mutation, Ndst1b2b2230Clo, and may be present in stocks carrying this mutation.