DNAH11 and Azoospermia: In addition, studies have shown that mutations in the DNAH5 gene may cause infertility symptoms such as azoospermia or oligozoospermia.[4,10] At present, the relationship between DNAH5, DNAH11 genes, and male infertility is not clear, but DNAH5 and DNAH11 are important components of the flagellar external axis silk power arm, and are highly conserved among different species; DNAH5 or DNAH11 gene mutations will lead to low sperm motility.