QRICH2 encodes a glutamine-rich protein essential for sperm flagella biogenesis and male fertility. Mechanistically, QRICH2 stabilizes proteins involved in flagellar development and acts as a suppressor of ubiquitin-dependent protein degradation 1. Recent evidence reveals QRICH2 functions as a glutamine sensor regulating microtubule glutamylation, which is critical for flagellar structural integrity and sperm motility 2. Additionally, QRICH2 possesses profound antioxidant properties that protect spermatids from reactive oxygen species (ROS)-induced DNA damage, autophagy, and apoptosis, thereby promoting spermatozoa survival 3. QRICH2 interacts with AKAP4 in the sperm fibrous sheath, and disruption of this interaction impairs flagellar development 4. Loss-of-function mutations in QRICH2 cause multiple morphological abnormalities of the sperm flagella (MMAF) and nonobstructive azoospermia, with homozygous variants identified in infertile males 15. Heterozygous QRICH2 variants are associated with asthenozoospermia and sperm tail defects 6. Whole-genome sequencing studies identify QRICH2 among candidate genes for nonobstructive azoospermia 7. QRICH2 represents a critical genetic target for understanding idiopathic male infertility pathogenesis.