SUN5 and spermatogenic failure 5: For example, Malhotra [73] reviewed the genetic basis of sperm head defects, including globozoospermia, macrozoospermia and acephalous sperm syndrome, highlighting the role of such genes as AURKC (aurora kinase C), DPY19L2 (dpy-19 like 2) and SUN5 (Sad1 and UNC84 domain containing 5) in spermatogenesis and fertilization.