CRISPR/Cas9 mutagenesis generated a 17 bp deletion in exon 4 which encodes the methyltransferase domain. Western blot analysis showed that protein expression levels were undetectable in all tissues tested in homozygous mutant mice. No tri-methylation of electron transfer flavoprotein beta subunit (ETFB) was detected in liver samples from homozygous mutant mice. (J:260200)