Vacuolated PAS-positive lymphocytes as an hallmark of Pompe disease and other myopathies related to impaired autophagy.

Autosomal recessive Pompe disease is a lysosomal disorder caused by mutations of the acid-α-glucosidase (GAA) gene. Deficiency of GAA enzyme leads to glycogen accumulation and autophagy impairment in cardiac and skeletal muscles, but also in lymphocytes. Since an effective therapy is available, a rapid, sensitive, and specific test is crucial to early identify affected subjects.