This allele from project TCPR0899 was generated at The Centre for Phenogenomics by electroporating Cas9 ribonucleoprotein complexes containing 4 guide RNAs with spacer sequences of GGACATTTGGAGTATCCAGA and GTGCTCTTGCCGCTTTGAGT targeting the 5' side GGTCTTATTCTTATCGACTA and CCTAGATCATAATATGTAAC targeting the 3' side of exons ENSMUSE00001275430 and ENSMUSE00001257593 resulting in a 1479-bp del in Chr4:99740974 to 99742452_insATGGTTTA (GRCm38).