HMCN2 (hemicentin 2) is an extracellular matrix protein that functions as a structural constituent and plays roles in cell adhesion and axon guidance. Based on GO annotations, HMCN2 exhibits axon guidance receptor activity and participates in homophilic cell-cell adhesion, with localization to the extracellular matrix, plasma membrane, neuronal cell bodies, axons, and synapses where it contributes to synapse organization. The gene demonstrates significant clinical relevance across multiple disease contexts. In cardiovascular disease, HMCN2 variants near chromosome 9 show genome-wide significant association with ECG global electrical heterogeneity phenotypes, with the locus significantly associated with HMCN2 gene expression in the left ventricle 1. In periodontal disease, HMCN2 shows the second strongest association (p = 6.1 × 10-8) with severe stage III/IV grade C periodontitis diagnosed at age ≤35 years 2. The gene is also implicated in hernia susceptibility, with Japanese studies identifying HMCN2 as an important locus for genetic predisposition to inguinal hernias 3. Additionally, HMCN2 mutations are associated with hemophagocytic lymphohistiocytosis in primary bone marrow large B-cell lymphoma 4, and the gene shows correlation with CD8+ T cell infiltration and cytotoxicity in breast cancer 5. These findings suggest HMCN2 plays important roles in tissue architecture, immune responses, and disease susceptibility across multiple organ systems.