Collagen fibril abnormalities in the extraocular muscles in Ehlers-Danlos syndrome.

The dermal collagen fibrils and the fibrils of the extraocular muscles and the conjunctivas of both eyes of a child afflicted with Ehlers-Danlos syndrome (EDS) were studied ultrastructurally. The results were evaluated statistically. Biopsy material was used in all instances. The collagen fibrils from all involved tissues showed a high percentage of size variation. Abnormalities of shape were noted. In the reticular dermis, 48% of fibrils were of normal diameter, 23% were enlarged, and 29% were thinner than normal. In the extraocular muscles, 77% were of normal size, 14.5% were larger, and 8.5% were smaller. In the conjunctivas, 73% of fibrils were normal-sized, 22% were enlarged, and 5% were of small diameter. No small-sized fibrils were encountered in control extraocular muscles.