The collagen fibril and EDS. (a) Normal collagen fibrils are of uniform size and spacing. Fibrils from a patient with dermatosparaxis (b) show dramatic alterations in fibril morphology with severe effects on tensile strength of connective tissues. Most fibrils from a patient with classical EDS (c) are normal in appearance. Composite fibrils (arrows) are typically rare. Fibrils from a TNX-deficient patient (d) are uniform in size and no composite fibrils are seen. When compared with normal skin (e), TNX-null fibrils are less densely packed and not as well aligned to neighboring fibrils. In normal skin (e) and cornea (f), fibrils are deposited in tissue-specific patterns. In skin, bundles of fibrils are oriented in different directions to resist forces in multiple axes. In cornea, orthogonal arrays allow maximal transparency.