CRISPR/Cas9 genome editing technology was used to generate c.1298_1299insA, which has a single adenine (A) inserted in exon 8. This allele is predicted to form a truncated protein (p.Q433Qfs10) and is referred to as EspnlA. No immunoreactivity was detected in mice homozygous for this mutation using the BG35961 anti-ESPNL antibody.