Chondrodystrophic Myotonia – A report of two unrelated Dutch patients

A comparison of the findings in two unrelated Dutch patients with chondrodystrophic myotonia with those in the patients reported so far may contribute towards a more exact delineation of the syndrome:

The skeletal system is involved in many ways. The patients are dwarfs with a retarded skeletal growth but with a normal head circumference. Other abnormalities are: high arched palate, short horizontal arch of the mandible, low implantation of ears, pigeon breast deformity, flattened vertebrae, dysplastic hips and talipes. There are many expressions of the affliction of the muscular system. It is firmly hypertrophic in the boys and normal or partially hypo- or hypertrophic in the girls. There is myotonia in many muscle groups. The blepharospasm, the frozen smile, the high pitched nasal voice, stridulous respiration, and the impaired range of motion (mostly in the proximal joints), are most probably results of the muscular involvement. Enzyme studies and biopsy studies by the light- and electron microscope revealed myopathic features in most of those reported in the literature and in both of our patients. In both of our patients, an elevation of the first fractions of the L. D. H. isoenzymes, myopathic phenomena in the E. M. G. and an increased average fiber diameter were discovered, which have not been reported up to now. Some subclinical muscular abnormalities were traced in the family members of our patients. The intelligence of the patients is mostly normal; the syndrome is not manifest until in the third year of life. There appears to be an autosomal recessive heredity. Treatment is restricted to physical therapy. Prognosis is presently unknown.

Myotonia - blepharospasm - muscular hypertrophy - dwarfism - skeletal deformities