DNAH6 (dynein axonemal heavy chain 6) encodes a force-generating motor protein of respiratory cilia and sperm flagella 1. As a component of inner dynein arms, DNAH6 produces ATP-dependent force toward microtubule minus ends, enabling ciliary and flagellar beating 2. DNAH6 mutations cause multiple morphological abnormalities of sperm flagella (MMAF) characterized by absent or shortened flagella and ultrastructural defects including loss of inner dynein arms and mitochondrial damage 3. These mutations result in severe asthenoteratozoospermia and male infertility, though intracytoplasmic sperm injection achieves favorable reproductive outcomes in affected couples 34. Beyond male infertility, DNAH6 variants contribute to heterotaxy—a left-right patterning birth defect—potentially through trans-heterozygous interactions with other ciliary genes like DNAH5 and DNAI1 5. DNAH6 knockdown disrupts motile cilia in Kupffer's vesicle and respiratory epithelium, demonstrating its essential role in left-right axis determination and airway clearance 5. Additionally, DNAH6 deficiency disrupts assembly of the axonemal 96 nm repeat unit in primary ciliary dyskinesia 2. These findings establish DNAH6 as critical for both reproductive and respiratory ciliary function with implications for genetic counseling in ciliopathy diagnosis.