Calcified ligamenta flava in a patient with Coffin-Lowry syndrome: biochemical analysis of glycosaminoglycans.

Glycosaminoglycans in calcified cervical ligamenta flava from a male patient with Coffin-Lowry syndrome were analyzed biochemically. Hexuronate content based on the tissue dry weight was 8-fold and 5-fold concentrated in the calcified center as compared with the peripheral area and with age-matched, normal ligamenta flava, respectively. Two-dimensional electrophoresis of glycosaminoglycan preparations on cellulose acetate film revealed that, although dermatan sulfate was the major glycosaminoglycan in the normal ligamenta flava, chondroitin sulfate was the predominant glycosaminoglycan in the pathological tisuse. Relative amounts of chondroitin sulfate disaccharide units were determined after digestion of glycosaminoglycans with chondroitinase, and the ratio of chondroitin 6-sulfate to chondroitin 4-sulfate tended to decrease with the distance from the calcified center to the peripheral area. These observations suggest that an alteration in glycosaminoglycan metabolism may be a contributing factor in calcification of ligamenta flava in Coffin-Lowry syndrome.