Expanding the phenotype of late-onset Pompe disease: tongue weakness: a new clinical observation.

INTRODUCTION Following the clinical observation of lingual weakness in 2 patients with late-onset Pompe disease (LOPD), tongue strength was assessed in 19 consecutive patients to determine the frequency and severity of this neurological sign. METHODS Lingual strength was assessed using manual muscle testing; if weakness was present, severity was established as mild, moderate, or severe. RESULTS All the patients exhibited lingual weakness, even 2 asymptomatic patients with a positive family history. Weakness was mild in 12 (63%), moderate in 6 (32%), and severe in 1 (5%). Dysarthria and/or dysphagia were observed or reported in 7 of 19 (37%) patients. CONCLUSIONS Lingual weakness may be present as an axial sign of LOPD, even relatively early in the disease course, and may contribute to the differential diagnosis of this now treatable condition. Dysphagia and/or dysarthria may also occur. This finding further expands the phenotype of LOPD.