diseaseassociated

Disease-associated, often written as disease-associated, is an adjective used in medicine and genetics to describe factors that occur more frequently in people with a given disease than in those without it. Such factors can include genetic variants, genes, proteins, biomarkers, environmental exposures, or clinical traits. Associations are typically identified through epidemiological studies, case-control or cohort analyses, and genetic approaches such as genome-wide association studies and linkage analysis. Distinguishing association from causation is essential: a disease association signals a relationship, but does not by itself prove that the factor causes the disease.

Applications and examples: A disease-associated variant or gene is one linked to disease risk or differential expression in affected individuals. Disease-associated biomarkers may aid diagnosis or prognosis. Examples include BRCA1 and BRCA2 variants linked to breast and ovarian cancer risk; HLA alleles associated with autoimmune diseases; the APOE ε4 allele associated with higher Alzheimer’s disease risk; and APOL1 variants linked to kidney disease in people of African ancestry. Many associations are context-specific, with effect sizes varying by population and often part of a polygenic or multifactorial basis.

Databases and interpretation: Curated resources such as ClinVar, OMIM, and the GWAS Catalog annotate disease-associated variants and genes. Interpretations weigh effect size, replication across studies, population background, and biological plausibility. Limitations include confounding, population stratification, multiple testing, and the possibility that an association reflects linkage rather than direct causality.