The molecular lesion is a T-to-C substitution in the Crkl gene, at position Chr16:17,452,790 (GRCm38). This nucleotide substitution resides 2 nucleotides downstream of exon 1. The mutant transcript is predicted to result in a loss of a putative splice donor and/or generation of additional exonic splice enhancers. Mutant embryos exhibit a loss of transcript expression compared to controls. Western blot analysis of protein extracted from whole E13.5 embryos confirmed the loss of protein in mutant mice. (J:251775)