Abnormality of dermal collagen fibrils in Ehlers Danlos syndrome. Anticipation of the abnormality for the inherited hypermobile disorders.

The abnormality of dermal collagen fibrils is the ultrastructural criterion of Ehlers-Danlos syndrome (EDS). This study evaluates the clinical significance of the abnormality. Besides 348 lax patients presenting the stigmata of EDS, skin specimens from 12 normal members in the pedigree of EDS, 98 randomly selected normal individuals, 7 Marfan syndrome and 4 osteogenesis inperfecta type I, were studied by electron microscopy. The abnormality was defined by thickness, array and shape of collagen fibrils. Of 348 lax patients, 115 patients showed Beighton's score higher than 6 and constantly the abnormality (EDS). Variable numbers of the patients with scores 1 to 5 displayed the abnormality (forme fruste). The abnormality did not correspond with variation of laxity. Marfan syndrome and osteogenesis imperfecta were indistinguishable from EDS by the abnormality. Some of the normal persons in the EDS pedigree and some controls also showed the abnormality. The abnormality expressed the disposition for heritably defected collagen fibril formation.