Clinical and pathologic features in 71 cases of distal myopathy / 中华神经科杂志

ABSTRACT

Objective To study the clinical manifestations and pathological features of distal myopathies, we investigated 71 distal myopathy patients collected in the past 16 years.Methods Clinical manifestations and pathological features of biopsied muscle specimens were summarized and analysed retrospectively. Results Twenty-six of the 71 patients were of Nonaka type, 38 of Miyoshi type, 2 of tibial muscular dystrophy (TMD) type, 4 of Welander type, and 1 of oculophayngodistal myopathy (OPDM) type. Nonaka type is a sporadic or autosomal recessively inherited disorder with preferential involvement of the anterior tibial muscles. In the 26 patients with Nonaka myopathy, the onset age ranged from 8 to 39 years, averaging 24 years, and the disease was rather rapidly progressive. Sternocleidomastoid, biceps brachii muscle, pectoralis major muscle and quadriceps femoris were also involved as the disease advanced. The serum CK was slightly elevated or normal. Muscle biopsies showed rimmed vacuoles markedly without obvious dystrophic features. 15-20-nm cytoplasmic and nuclear filaments were usually seen on electron microscope. The patients with Miyoshi type were characterized clinically by sporadic or autosomal recessive inheritance, preferential gastrocnemius muscle involvement, and dystrophic muscle pathology. Rimmed vacuoles were occasionally seen. Average age of onset was 23 years (range of 8-41 years). As the disease advanced, patients with Miyoshi myopathy occasionally showed apparent proximal muscle involvement. Serum CK was markedly elevated, ranging from 3-180 times than the normal. Welander type was found in four cases. Onset age was from 30 to 46 years. Weakness always began in the finger and wrist extensors. As the disease progressed, symptoms were spreading to the distal lower extremities slowly. The serum CK level was normal or only slightly elevated. Muscle biopsies showed dystrophic features, with rimmed vacuoles occasionally. The oneset ages of two patients with TMD were from 41 to 42 years. Weakness was confined mainly to the anterior tibial muscle. Muscle biopsies revealed fibre necrosis and regeneration. Rimmed vacuoles were present significantly. OPDM was found in a 38-year-old-onset patient with autosomal dominant inheritance and characterized by the weakness of distal lower extremity and development of extraocular muscles, vocal cord and pharyngeal muscle weakness. Muscle biopsies showed rimmed vacuoles without fibre necrosis.Conclusion Five types of distal myopathies were present in China, and Miyoshi and Nonaka myopathies were more common. The clinical and pathological findings of Chinese distal myopthies should be basically similar to those reported by other countries.