The β-actin and its capping proteins are known to be abnormally regulated in patients with oligozoospermia and asthenozoospermia (Inagaki et al., 2021) and an abnormal regulation of testis-specific actin capping protein CPβ3 was described in sub-fertile patients (Soda et al., 2017). The gene discussed is TMOD4; the disease is Reduced sperm motility.