Bone anomalies in myotonic dystrophy.

Sixteen patients with myotonic dystrophy underwent CT examination of the skull, and measurement of bone mineral density at lumbar spine and hip by dual-photon absortiometry. The results were compared with those of 20 normal subjects of similar age and sex distribution. Hyperostosis of the calvarium, and increased bone mineral density at lumbar vertebrae were observed. One case showed basal ganglia calcification associated with hyperparathyroidism secondary to deficiency of vitamin D. In the other 15 patients, studies of calcium metabolism were normal. There results suggest the existence of generalized hyperostotic potential in patients with myotonic dystrophy.