Multiefaktoriline

Multiefaktoriline, often equivalent to multifactorial in English, describes traits or conditions that arise from the combined effect of multiple genetic factors and environmental influences. In contrast to single-gene (monogenic) traits, multifaktoriline traits result from the cumulative action of many genes, each contributing a small effect, together with non-genetic factors such as nutrition, lifestyle, and exposure to environmental conditions. The genetic component is typically polygenic and additive, while environmental factors can modify expression and risk.

Mechanisms underlying multifaktoriline traits include gene-gene interactions, gene-environment interactions, and epigenetic modifications that influence how genetic information is expressed. Heritability estimates for multifaktoriline traits reflect population-level contributions of genetic variation, but they do not determine outcomes for individuals. Risk often follows a probabilistic rather than deterministic pattern.

Study and prediction of multifaktoriline traits rely on population-level approaches, including family and twin studies, genome-wide association studies (GWAS), and the development of polygenic risk scores that quantify an individual’s predisposition based on many genetic variants. These tools help in risk assessment, personalized prevention, and public health planning, though they have limitations in predictive accuracy for individuals and across diverse populations.

Common examples include height, body mass index, and several common diseases such as type 2 diabetes, coronary artery disease, and certain congenital anomalies like neural tube defects or orofacial clefts. Understanding multifaktoriline traits emphasizes the interplay between genetics and environment in shaping complex human phenotypes.