Protein aggregate myopathies. Introduction.

摘要

Protein aggregate myopathies (PAMs) are a recently emerging group of neuromuscular conditions marked by aggregation of proteins within muscle fibers. They belong to the larger group of protein aggregate disorders (PADs), among which protein aggregate encephalopathies (PAEs) now form the major part of neurodegenerative diseases of the brain, such as Parkinson's and Alzheimer's diseases. Other central nervous system PADs include frontotemporal dementia affecting nerve cells, Alexander disease affecting astrocytes, as well as multiple system atrophy affecting oligodendrocytes. There is also a still small cohort of protein aggregate neuropathies (PANs) characterized by protein aggregation within axons and Schwann cells, with the foremost among these being giant axonal neuropathy. Other peripheral nerve diseases associated with enlargement of axons by excessive neurofilament assembly (Table 1) are further examples of PANs. In general, these PADs may be divided into hereditary and nonhereditary forms. Each of these types actually exists among PAM, PAE and PAN. Mutant proteins in PAD most likely initiate the aggregation of proteins in many hereditary forms, while the pathogenetic principles in acquired PAD are still enigmatic.