Three cases of myotubular myopathy (8 years girl, 9 years girl and 13 years boy) were reported. Age of onset was at birth in 2 cases and 1 year after birth in one case. No heredity was found in all cases.
The clinical course was progressive in 2 cases and stationary in one case. Neurological examinations revealed proximal dominant muscular weakness, decreased deep reflexes, facial muscle weakness and no sensory disturbances in all cases, abnormalities of ocular movement in 2 cases and impairment of intelligence in one case.
Muscle biopsy showed centrally situated nuclei, halo around the nuclei and type I fiber atrophy which are characteristic to myotubular myopathy. Electromyographic findings were low amplitude potential, short duration and fibrillation potential. Values of serum enzymes were within normal limit. Blood chemistries were all negative.
Fairly close relation was found between clinical progression and ratio of the affected fibers observed in muscle biopsy.
Pathogenisis of this disease was discussed from the clinical and pathological findings.
