SPATA22 is a meiosis-specific protein essential for homologous recombination during gametogenesis. It functions as a binding partner of MEIOB, forming a heterodimer critical for meiotic progression 1. SPATA22 interacts with MEIOB to expose a nuclear localization signal, enabling MEIOB's nuclear import and proper chr17 localization on single-strand DNA (ssDNA) 2. The MEIOB-SPATA22 complex binds ssDNA with high affinity and stability, cooperating with RPA to form a compacted ssDNA-binding complex that regulates meiotic recombination intermediates 3. SPATA22 enhances ssDNA binding kinetics and promotes DNA condensation 4. Mutations in SPATA22 cause meiotic arrest at the zygotene-like stage, preventing double-strand break repair and crossover formation 5. Clinically, biallelic SPATA22 variants cause premature ovarian insufficiency in females and nonobstructive azoospermia in males 51, making it the first identified causative gene for familial premature ovarian insufficiency. SPATA22 mutations represent a significant genetic basis for human infertility and potential targets for genetic diagnosis 1.