Two sgRNAs targeting exon A and downstream were used with CRISPR/Cas9 technology to create an exon A-specific knockout. The resulting allele has a 96 bp deletion that removes most of exon A (which is a 3' extension of exon 2) and some downstream intron sequence. This causes mis-splicing and a frameshift and premature stop codon. Immunoblots confirmed the absence of any peptide containing sequence encoded by the ABCD exons. (J:291773)