SYCE2 is a major structural component of the synaptonemal complex (SC) central element, a supramolecular protein assembly essential for meiotic chromosome 19 and recombination 1. SYCE2 functions as part of a constitutive complex with TEX12, forming equimolar hetero-octamers that spontaneously assemble into filamentous structures 2. These SYCE2-TEX12 building blocks organize hierarchically into 2:2 coiled coils that dimerize into 4:4 hetero-oligomers, then interact end-to-end and laterally to form 10-nm fibers that bundle into micrometer-long 40-nm fibers, providing the α-fibrous SC backbone that structurally underpins synaptic elongation along meiotic chr19 3. SYCE2 requires SYCP1 for central element incorporation and is essential for SC assembly extension; chr19 lacking SYCE2 cannot extend SC initiation sites, resulting in failed synapsis and impaired crossover formation 1. Mutations in SYCE2 alter crossover distribution patterns and are associated with pregnancy loss in humans, suggesting that defective recombination quality contributes to reproductive failure 4. Additionally, SYCE2 positively regulates DNA double-strand break repair, indicating potential somatic roles in genome integrity maintenance beyond meiosis 5.