Twin study method: Unlocking genetic and environmental interactions

Abstract

Twin studies offer a powerful approach for disentangling genetic and environmental influences on human traits. By comparing monozygotic twins with identical genetic makeup, researchers can more accurately identify the environmental contributions to phenotypic variation. Structural equation modeling provides a theoretical framework for estimating the relative contributions of additive genetic effects, shared environmental factors, and unique environmental influences. This model allows researchers to determine the most suitable parameters for explaining the observed data in twin populations. In addition, bioinformatic tools enable in-depth analyses of phenotypically discordant monozygotic twin pairs, helping to uncover both environmental sensitivities and genetic predispositions. This review examines the advantages and limitations of twin study methodologies in research on endocrine disorders, lipid metabolism, and thyroid function. Findings from twin cohorts have enhanced our understanding of heritability, environmental modifiers, and epigenetic factors, offering valuable insights into gene–environment interactions. Overall, twin studies remain critical tools in genetics, endocrinology, and obesity research. In the future, genetic information may enable the development of optimal personalized environments, ultimately providing valuable insights that contribute to physical, mental, and social well-being throughout the lifespan.