Late-Onset Pompe Disease (Juvenile-Onset Form) with Elevated CK, Fatigue, and Muscular Pain After Exercise, Without Weakness.

An 11-year-old Caucasian female, the fi rst child born to healthy unrelated parents after a normal gestation and parturition, had adequate neuropsychomotor development. At the age of 10 years she was diagnosed with mononucleosis. Laboratory investigations demonstrated elevated AST/ALT. These investigations were repeatedly carried out, and AST/ALT remained elevated. The girl complained of body pain and fatigue after non-strenuous exercise. Her CK was investigated and found to be twice that of normal. Metabolic myopathy was suspected. Ischemic and fasting tests were negative. EMG was normal. She had muscular pain after light running, but no muscular weakness. A dry blood spot (DBS) test and muscular biopsy were then carried out. The muscle biopsy showed vacuolar myopathy with some vacuoles inside the fi bers containing increase glycogen (PAS) and increased lysosomal activity on acid phosphatase reaction. DBS revealed severely reduced GAA activity (0.4 μmol/l/h of protein – normal value: >3 μmol/ l/h). Gene sequencing: GAA showed two heterozygous Late-Onset Pompe Disease (Juvenile-Onset Form) with Elevated CK, Fatigue, and Muscular Pain After Exercise, Without Weakness