Friedreich cardiomyopathy is a secondary desminopathy

Koeppen, A., Rafique, R., Mazurkiewicz, J., Pelech, S., Sutter, C., Lin, Q., & Qian, J. (2021). Free Neuropathology, 2, 34. doi:10.17879/freeneuropathology-2021-3679 

A proteomic analysis of heart proteins in FA cardiomyopathy by antibody microarray, Western blots, immunohistochemistry, and double-label laser scanning confocal immunofluorescence microscopy revealed upregulation of desmin and its chaperone protein, αB-crystallin. In normal hearts, these two proteins are co-localized at intercalated discs and Z discs. In FA, desmin and αB-crystallin aggregate, causing chaotic modification of intercalated discs, clustering of mitochondria, and destruction of the contractile apparatus of cardiomyocytes. Western blots of tissue lysates in FA cardiomyopathy reveal a truncated desmin isoprotein that migrates at a lower molecular weight range than wild type desmin. While desmin and αB-crystallin are not mutated in FA, the accumulation of these proteins in FA hearts allows the conclusion that FA cardiomyopathy is a desminopathy akin to desmin myopathy of skeletal muscle.