The ultrastructural characteristics of abnormal collagen fibrils in various organs.

Quite unrelated diseases affecting different organs can lead to the appearance of abnormal collagen fibrils, which may be due to genetic disorders, transformation of mesenchyme cells, increased collagen synthesis or a change in the ground-substance. The simultaneous appearance of abnormal collagen fibrils and matrix vesicles containing lysosomal enzymes in the majority of our electron photomicrographs suggests an alteration in the ground-substance as a main cause of non-hereditary collagen dysplasia.