Calcium crystal-associated diseases and miscellaneous crystals.

Calcium crystal-associated diseases are still a challenge in clinical and basic science. Advances in understanding crystal formation and dissolution and crystal participation in inflammation are reported here. Studies on different methods of identification are reviewed, emphasizing the need for accurate and reproducible ways to study and diagnose calcium crystal-associated diseases. Reports of uncommon presentations are also described, including a controlled study on calcification of the ligamenta flava of the spine and a study involving 19 years of clinical follow-up of families with hydroxyapatite chondrocalcinosis with spondyloepiphyseal dysplasia. Studies on miscellaneous crystals are few. Two recent reviews are described on cholesterol crystal embolization syndrome and cryocrystalglobulinemia.

Hereditary chondrocalcinosis in a Mexican-American family.

In a study of 45 adults in a family of Mexican-Indian ancestry, it was found that 22 (49%) had joint symptoms resembling those of degenerative joint disease. Eleven family members had radiographic evidence of chondrocalcinosis, and 1 adult and 3 adolescents had clinical histories and examinations consistent with the familial arthropathy, but no radiographic evidence of disease. The cause of the arthritis in the affected family members is calcium pyrophosphate crystal deposition. The mode of inheritance appears to be autosomal dominant with a high degree of penetrance. The disease is characterized by onset in the second to fifth decades of either episodes of acute inflammatory arthritis or degenerative joint disease. A unique finding of this study was a "halo" surrounding chondrocytes in 1 patient's cartilage, demonstrating loss of the proteoglycans.