H3C1 (H3 clustered histone 1) is a histone gene located on chromosome 6 that functions as a structural constituent of chr6 and plays a role in epigenetic regulation of gene expression 1. The gene is involved in nucleosome assembly, chr6 organization, and heterochromatin formation, with protein binding and localization in the nucleus and nucleoplasm 1. H3C1 has emerged as a significant disease-associated gene across multiple pathologies. In gliomas, H3C1 mutations drive epigenetic remodeling that contributes to gliomagenesis and tumor progression by altering histone modifications and chr6 structure, with downstream effects on the tumor microenvironment and immunotherapy responses 1. In prostate cancer, H3C1 variants are associated with increased genetic risk in Black South African men 2. H3C1 has been identified as a predictive biomarker for schizophrenia in peripheral blood, correlated with immune cell populations including neutrophils and natural killer cells 3. In endometrial cancer, H3C1 was incorporated into a prognostic model predicting patient outcomes based on inflammation and lipid metabolism signatures 4. Additionally, H3C1 mutations show racial enrichment in clonal hematopoiesis of indeterminate potential, being more prevalent in Asian populations 5. During calorie restriction-induced weight loss, H3C1 expression negatively correlates with strength preservation, suggesting a role in skeletal muscle metabolism 6. These findings indicate H3C1 functions broadly in epigenetic regulation with implications for cancer biology, immune responses, and metabolic disease.