Delayed or late-onset type II glycogenosis with globular inclusions

Three unrelated patients, one girl, one boy, and an adult female, aged 14, 11 and 41 years, respectively, at the time of biopsy, revealed lysosomal glycogen storage, autophagic vacuoles and peculiar globular inclusions of distinct ultrastructure, which were reducing but did not appear like true “reducing bodies” as described in the congenital myopathy “reducing body myopathy”. All three patients had residual activity of acid α-glucosidase in their muscle biopsy samples. Leukocytes in the girl showed normal acid α-glucosidase activity, but in the boy activity was reduced. Molecular genetic analysis of the GAA gene revealed disease-causing mutations in each patient: H568L/R672W, IVS1–13T>G/G615F, and IVS1–13T>G/IVS1–13T>G. Although only one patient with such globular inclusions has been reported up to now, the three patients described here indicate that in the late-onset type of GSD II such inclusions may not be rare.