Delayed diagnosis of late-onset Pompe disease in patients with myopathies of unknown origin and/or hyperCKemia.

Pompe disease is a rare metabolic myopathy whose diagnosis is sometimes delayed despite being essential for improving clinical outcomes. We aimed to investigate the prevalence of late-onset Pompe disease among patients with a myopathy of unknown etiology, including polymyositis, or with idiopathic rise of creatine kinase (CK) levels, in a department of internal medicine. A cohort study was conducted in 241 subjects: 140 patients with myopathies of unknown origin or increased CK levels, 30 with polymyositis and 71 who constituted the control group of other myopathies. Acid α-glucosidase (GAA) activity was tested in dried blood spots. If a positive result was obtained, GAA activity in isolated lymphocytes and/or genetic testing was performed as a confirmatory diagnosis. Out of the 140 investigated patients, 2 patients with myopathies of unknown origin were confirmed to be positive for Pompe disease. Thus, late-onset Pompe disease should be considered among adult patients with myopathy of unknown origin.