Ultrastructural aspects of chondrodystrophia calcificans congenita (syndrome of Conradi-Hünermann).
An ultrastructural study of chondrodystrophia calcificans congenita is reported. Foci of initial calcification of cartilage are characterized by coexistence of three different types of crystals, probably due to abnormal proteoglycan composition of cartilage matrix. The calcification process in chondrodystrophia calcificans congenita is apparently not related to 'matrix vesicles' as it is in normal cartilage.