This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. The molecular lesion is a G to A substitution at nucleotide +1 after coding nucleotide 26 (c.26+1G>A, NM_001085505) in intron 1. This changes splice donor site G-GT to G-AT (which is assumed to be inactive). (J:175213) Additional incidental mutations were detected in sequencing for the causative mutation, Gm572b2b1167Clo, and may be present in stocks carrying this mutation.