CRISPR/Cas9 technology using sgRNA 5-AGCATTCTTTGGCCTCAGCA-3 deleted 16 bp within exon 25, generating a stop codon after amino acid 1007. Western blot analysis confirmed a truncated protein lacking tetratricopeptide repeats (TPRs) 5-8 in testis lysates. Amino acid 1008 in mouse is homologous to the position of the 988th amino acid in the human. A nonsense variant c.2962C>T/p.R988X that produces a truncated protein lacking the TPRs was identified in a patient with oligo-astheno-teratozoospermia. (J:338031)