Infantile autophagic vacuolar myopathy is distinct from Danon disease

Lysosomal glycogen storage disease with normal acid maltase (Danon) is caus ed by primary lysosome-associated membrane protein-2 (LAMP-2) deficiency. T ypically, the disease begins after the first decade; however, two infantile patients had similar histologic features. The infantile disorder is distin ct from Danon disease, because, in both infants, LAMP-2 protein is present in skeletal muscle. Deposition of C5b-9 and multilayered basal lamina in on e patient suggest that the infantile disease is pathogenically similar to X -linked myopathy with excessive autophagy.