Acid alpha-glucosidase deficiency, i.e. Pompe disease, is a glycogenosis for which enzyme replacement therapy (ERT) is available. It is not known whether patients diagnosed at an asymptomatic stage should be treated in order to prevent progression of the disease. Here, the authors investigated 7 patients with asymptomatic Pompe disease identified from the French Pompe registry. The patients had a mean age of 45 years (24-75), a median follow-up duration of 2 years (1-22), and normal clinical examination, pulmonary function tests (PFT), and echocardiography. All presented with at least 1 subclinical abnormality, including hyperCKemia, vacuolar myopathy, and muscle magnetic resonance imaging (MRI) abnormalities, suggesting that subclinical myopathy was present in all cases. Asymptomatic Pompe disease may remain clinically silent for decades, and affected patients should be monitored closely for overt myopathy using clinical examination, PFTs, and muscle MRI in order to determine when to start ERT.
