Glutamic acid codon 332 (GAA) in exon 7 was changed to glutamine (CAA) (p.E332Q) using crRNA, tracrRNA and an ssODN template with CRISPR/Cas9 technology. This mutation, in the N-terminal RecA module of the RNA helicase domain, inactivates the protein's ATPase and RNA helicase activities. (J:328765)