[Distal myopathies: clinical, laboratory, electromyographic, histologic-histochemical analysis of 8 cases].

Distal myopathies are uncommon diseases presenting difficulties in the classification by the lack of sufficient knowledge on pathogenesis. We describe eight cases of distal myopathies (five male and three female patients) whose symptoms started at the age of 10 in five and 20 in three. Symptoms started in the distal muscles of lower limbs, following decreased strength in the distal portion of upper limbs, and later on involvement of proximal muscles. Serum enzymes increase was slight in five, moderate in one, and important in two. EMG suggested primary myopathy in four, denervation in two, and was mixed type in another. Muscle biopsies showed features of myopathy and denervation in two cases, active chronic myopathy in five, and chronic myopathy in another. Four cases had vacuoles with positive acid phosphatase reaction and in two cases rimmed vacuoles were found. Six cases had increase of focal phosphatase acid in the muscle fibers suggesting a lissome participation in the pathogenesis of the disease. Two cases were classified as recessive autosomal distal myopathy (Welander variant), two recessive autosomal (Miyoshi type), two autosomal recessive with rimmed vacuole (Myzuzawa and Nonaka type), and two as miscellany type.