Genetic influence on femoral plaque and its relationship with carotid plaque: an international twin study.

To disentangle genetic and environmental influences on the development of femoral plaques using a population of adult twins. To evaluate the potential role of shared genetic and environmental factors in the co-occurrence of femoral and carotid plaques. The sample included 566 twins belonging to 164 monozygotic (MZ) and 119 dizygotic (DZ) twin pairs, who underwent peripheral arterial assessment by B-mode ultrasound in different centers. The variance in femoral plaques onset was due to genetic factors and the remaining 50% was explained by common (15%) and unique (35%) environmental factors. Findings on sidedness and number of femoral plaques indicated that also these traits were mainly under genetic control. No effect of common environment was found on plaques composition, and variability of this trait was explained by genetics (64%) and unique environment (36%). Covariation between the liabilities to carotid and femoral plaques was mainly attributed to shared genes (77%), with the remaining 23% explained by individual-specific environmental factors shared by the two districts. Inter-individual differences in plaque onset as well as in their number, sidedness and composition are mainly genetic in origin. The results on the cooccurrence of carotid and femoral plaque underline the genetic role in atherogenesis.