Considering that the ADAD2 protein level was observed to be markedly reduced in the testes of the patients carrying MT1 and MT2 (Fig. 2A), and pathological histology showed defective spermiogenesis (Fig. 2C) consistent with the phenotype of Adad2KO mice (Snyder et al., 2020), we hypothesized that MT1 and MT2 were associated with male infertility. The gene discussed is ADAD2; the disease is male infertility.