[en] Ehlers-Danlos syndrome (EDS) is heterogenous with regard to genetic traits, clinical manifestation, the biomechanical and microscopic properties of connective tissues, and basic molecular defects. We report on nine relatives of four generations who suffered from large vessel dissections and cutaneous microscopic changes consistent with EDS. Measurements of the mechanical properties of skin were performed using a computerized suction device (Cutometer). Morphological and biomechanical alterations suggestive of EDS were present in all examined subjects. A loose network of collagen bundles was admixed with clumsy elastic fibres. Factor XIIIa-positive dermal dendrocytes looked almost normal but were slim and rarefied in four subjects. The severity in ultrastructural alterations of the collagen network differed among the subjects. The group with the most prominent changes showed the most striking biomechanical alterations characterized by increased biologic elasticity without any excess in skin extensibility. A positive correlation was found between skin extensibility and elasticity. In conclusion, distinct alterations in the collagen scaffolding were found to be correlated to variable severity in biomechanical alterations of the skin. The predictive value of these changes for large vessel dissections in some families at risk remains to be settled.