Cori/Forbes disease, or glycogen storage disease type III, is a rare hereditary genetic disease which causes deficiency of an enzyme that converts glycogen into glucose. It leads to hypertrophy of the liver, delayed growth in children and progressive muscle weakness.
What is Cori/Forbes disease?
Cori Forbes disease or glycogen storage disease type III is caused by a deficiency of the glycogen debranching enzyme. This enzyme plays a vital role in converting glycogen to glucose. When it malfunctions, glycogen builds up and becomes toxic to the muscles and the liver.
This disease generally manifests in childhood and leads to a variety of symptoms, including hypertrophy of the liver (which often regresses at adulthood), delayed growth and sometimes convulsions triggered by hypoglycemia, since the body does not produce enough glucose. Muscular weakness is often accompanied by hypotonia (decreased muscle tone) and hypertrophic cardiomyopathy.
There is currently no curative treatment. A special diet may be proposed.
Cori Forbes disease: Genethon’s role
A team from Genethon is working to re-establish expression of the debranching enzyme in the liver, muscles and heart of mice suffering from the same disease, via gene therapy to reduce glycogen build-up in these organs. Since the human GDE gene, which codes for this enzyme, is very large, it is difficult to insert and carry within a vector.
To resolve this issue, researchers at Genethon are developing original vectorization strategies to design a therapeutic product.
Cori Forbes disease: find out more
- Vidal, P. et al., 2018, Rescue of GSDIII Phenotype with Gene Transfer Requires Liver- and Muscle-Targeted GDE Expression, Molecular Therapy.