Congenital and metabolic myopathies of childhood or adult onset

Objectives: To investigate the clinical presentation, histological findings , and outcome of patients with congenital and metabolic myopathies (CM and MM) in whom the disease was diagnosed in childhood or adulthood. Patients and Methods: We reviewed the diagnosis of ail skeletal muscle biop sies performed by our group between 1984 and 1996 (13 years). All patients with CM and MM of childhood or adult onset were included in the study. Pati ents with mitochondrial myopathies were excluded because they are multisyst emic disorders with a more distinct picture than that observed in other MM. We retrospectively reviewed the clinical history, with special emphasis on the clinical patterns of presentation, histological findings, and outcome. Results: Among 1,865 biopsies, 28 (1.5%) fulfilled the diagnostic criteria for CM (seven nemaline myopathies, four multicore myopathies, three centron uclear myopathies) or MM (five adult-onset acid maltase deficiency, three m yophosphorylase deficiency, three phosphofructokinase deficiency, two carni tine palmitoyl transferase deficiency, and one carnitine deficiency). In ne arly half of the patients, mild stable weakness was the major complaint, wh ereas in one third muscular symptoms were intermittent and related to exerc ise. In a small number of cases, a persistently raised serum creatinkinase in an asymptomatic patient was the reason for muscle biopsy. Histological e xamination of skeletal muscle was highly indicative of a specific muscle di sease in 26 of the 28 cases. After a mean follow-up of 7 years, the outcome has generally been good, and in most patients the myopathy did not worsen, most remaining ambulatory. Conclusion: CM and MM presenting in childhood or adulthood are infrequent; the symptoms are usually mild or moderate, and the prognosis generally is g ood. Copyright (C) 2000 by W.B. Saunders Company.