Inclusion body myopathy

00:00 / 00:00



Inclusion body myopathy



Inclusion body myopathy


0 / 11 complete

High Yield Notes

6 pages


Inclusion body myopathy

of complete


In inclusion body myopathy, “myopathy” refers to muscle disease and “inclusion body” refers to the presence of inclusions, or vacuoles, formed by clumps of protein that collect within the muscle fibers.

There’s a sporadic form, sporadic meaning that it strikes at random, which is the most common and is also called inclusion body myositis - because it causes muscle inflammation.

There’s also a rare hereditary form, that causes no muscle inflammation.

Normally, the cells of the immune system are ready to spot and destroy anything foreign that could cause the body harm.

To help with this, most cells in the body have a set of proteins that come together to form a major histocompatibility complex, or MHC, class I proteins which sits on the surface of their cell membrane.

These surface proteins act kind of like a serving platter, presenting molecules from within the cell for the immune system, so that it can have a way of performing ongoing surveillance.

Normally the MHC class I proteins serves up a normal harmless molecule from the cell - a self-antigen, and there’s no response.

But if a cell is invaded by a pathogen like a virus, then viral proteins are served upon on the MHC class I proteins.

When these viral antigens are displayed on the cell surface, it sparks an immune response.

Specifically, a type of T-lymphocyte, called a CD8+ T-cell or a cytotoxic T-cell, will bind to the antigen presented by the MHC class I proteins.

If the cytotoxic T-cell binds strongly, than the antigen is recognized as foreign, and the cytotoxic T-cell secretes inflammatory molecules and enzymes - like perforin and granzymes.

Perforin is able to form holes in the infected cell and that allows the granzymes to enter the cell.

Once inside, the granzymes induce apoptosis, or programmed cell death - which destroys the cell.

And as if that weren’t enough, the cytotoxic T-cells have a protein called Fas ligand on their surface.

Fas ligand binds to a protein called Fas on the surface of the infected cell.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "GNE myopathy: from clinics and genetics to pathology and research strategies" Orphanet Journal of Rare Diseases (2018)
  6. "Hereditary inclusion-body myopathies" Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease (2015)
  7. "GNE Myopathy: Etiology, Diagnosis, and Therapeutic Challenges" Neurotherapeutics (2018)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.