SPIN2B is an X-linked nuclear protein that regulates cell cycle progression through histone H3K4me3 reader activity. The protein inhibits apoptosis following growth factor withdrawal in myeloid progenitor cells, providing approximately 25% protection from apoptosis compared to control conditions, and slows cell cycle progression by increasing the proportion of cells in G2/M phase. This anti-apoptotic function depends on its nuclear localization; cytoplasmic variants lose protective activity. SPIN2B is highly expressed in brain and nerve tissues. Recent X-chrX-wide association analysis in a South African cohort identified variants affecting SPIN2B expression as significant candidates in Parkinson's disease susceptibility, where female-stratified analysis revealed multiple expression quantitative trait loci affecting SPIN2B alongside related SPIN genes. The gene has been associated with diverse conditions including acute myeloid leukemia, Alzheimer disease, and neurodegeneration, though the mechanisms underlying these associations require further investigation.