Centronuclear Myopathy with Special Consideration of the Adult Form

Abstract

We report clinical, electrophysiological, enzyme histochemical and ultrastructural findings in 4 patients afflicted with centronuclear myopathy of adulthood whose disorder emphasizes the broad spectrum of this congenital myopathy including clear ocular ptosis in only one and facio-scapulo-peroneal syndrome in another patient. The morphological criteria for classification are central nuclei and the enzyme histochemical findings in muscle biopsies which did not show any significant progression over many years, more severe involvement of distal muscles in 2 patients and conspicuous presence of intrafascicular fat cells. 1 patient had associated minicores in a familial setting. Although electromyographic data comprised a mixed myopathic-neurogenic pattern, the morphological features in muscle biopsies did not further prove a neurogenic origin of our patients’ neuromuscular disorder.

Centronuclear myopathy: histopathological aspects in ten patients with chilfhood onset

“…This variability occurred in 80% of our cases. Usually, hypotrophied fibers are type I while hypertrophied are type II 12,14,15,16 , as observed in one of our cases. However, in some cases both type I and type II fibers may present hypotrophy or hypertrophy 36 , as occurred in four of our cases.…”

“…Type I fiber predominance, one of the main findings in CNM [3][4][5]11,12,15,16 , was seen in all our muscle samples. Four patients disclosed only type I fibers.…”

“…In our series of patients the percentage of nuclear centralization varied from 25% to 95%. This percentage may vary according to the muscle group examined, the type of sections (transversal or longitudinal) and the period in which the muscle biopsy is performed in a same patients 12,14,20,26,30 .…”

“…Another frequent finding in CNM is the increased variability in fiber size where there are hypotrohied fibers usually in a great number adjacent to normal size and hypertrophied ones 4,5,12,14,15,16 . This variability occurred in 80% of our cases.…”

“…During the course of CNM, hypotrophy of type I fibers and the percentage of nuclear centralization may either persist 11,12 or subside 26,31 . Worsening of the histological findings has also been observed 20,34 .…”