Conference Paper

Structural instability in Skin, Muscle, and Nerves in a Case of Epidermolysis Bullosa Simplex due to a Mutation of Plectin: Transmission Electron Microscopic Observations

Conference: 27th Ann.Meetg of SCUR(Society for Cutaneous Ultrastructure Research)& 12th ADF-Meeting, Volume: JID,115 No 5, p.926, O30

ABSTRACT The role of Plectin - a cytoskeleton linker protein - as an essential intermediate filament binding protein recently has been supported by reports on the development of blistering disease (Epidermolysis bullosa / EB simplex) with late onset muscular dystrophy in humans. We report on ultrastructural TEM-findings in skin, skeletal muscle, and intramuscular nerves of a now 6-year-old patient, offspring of unaffected parents with a compound heterozygous one amino-acid insertion / nonsense mutation in the plectin gene. Increased protein degeneration possibly caused by increased self-assembly of plectin molecules in skin seems to result in reduced and hypoplastic formation of hemidesmosomes in the DE-BM-zone, and irregular, if not missing insertion of tonofilament bundles into the hesmidesmosomes. On the other hand, skeletal muscle shows moderate fibrillar Z- and I-band alterations, at places a disoriented and "dystrophic" filament system, focally missing or defect sarcoplasmic membrane besides degenerative mitochondria, suggestive of moderate myopathic changes. Additionally, there was increased endo- and perimysial collagen proliferation and several intramuscular nerve cross sections exhibited dystrophic and/or degenerative alterations. These findings provide evidence for the central role of plectin in tissue intergrity. Additionally, it suggests a role of altered innervation in the variable onset of muscular weakness in such patients.

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Jun 4, 2014