Crystalline aggregates of protein-glycogen complexes (alias 'virus-like particles') in skeletal muscle: report of a case and review of the literature.

Crystalline arrays of so-called 'virus-like particles' were found in post-mortem samples of skeletal muscle obtained from an 11-month-old female infant. In a large number of skeletal muscle fibres crystalline inclusions were abundant, variously configurated and positively stained with a cytochemical method for polysaccharides. A battery of enzymatic tests, including some with diastase and alpha-amylase, was, however, entirely noncontributory. A muscle biopsy studied 5 months before death had disclosed no crystalline inclusions of any kind. The literature concerning similar cases of 'virus-like particles', crystalline glycogen aggregates or protein-glycogen complexes in muscle is reviewed. Possible reasons underlying the aggregation of protein-glycogen complexes into crystalline arrays are discussed.