TTLL5 and Azoospermia: The reported expression of TTLL5 within the inner ear of mice and the high frequency hearing loss seen in P2 and previously reported patients raise the possibility that truncating mutations in TTLL5 may cause syndromic disease that includes azoospermia, retinal findings, and high-frequency hearing loss (David He, MD, PhD, email communication, May 2020) [12–16].