DNAH17 encodes dynein axonemal heavy chain 17, a force-generating motor protein component of outer dynein arms (ODAs) in sperm flagella and motile cilia 1. It produces force toward microtubule minus ends through ATPase activity, essential for cilium and flagellum movement 2. DNAH17 is critical for sperm flagellar assembly, beating mechanics, and structural integrity of the axoneme 3. Loss-of-function mutations in DNAH17 cause multiple morphological abnormalities of sperm flagella (MMAF) with impaired outer dynein arm assembly and docking 3. Mutations disrupt axonemal protein levels including DNAH17 itself, affecting sperm motility and morphology 4. DNAH17 variants are associated with oligoasthenoteratozoospermia and male infertility 5, with autosomal-recessive inheritance patterns identified in multiple families 3. Clinically, DNAH17 mutations cause spermatogenic failure 39 and asthenozoospermia. Men with MMAF-harboring DNAH17 variants show poor outcomes with standard intracytoplasmic sperm injection (ICSI) but may benefit from ICSI combined with artificial oocyte activation 2. Notably, DNAH17 deficiency does not cause total fertilization failure after ICSI 3. Additionally, DNAH17 variants are enriched in hypospadias patients, linking ciliary dysfunction to urogenital development 6, and variants associate with left-right asymmetry disorders 7.