Researchers at The Hospital for Sick Children (SickKids) Research Institute have found the gene that causes X-linked myopathy with excessive autophagy (XMEA).
Scientists studied the component in the cell called an autophagosome. This component breaks down the materials within a cell that are to be recycled. An enzyme called V-ATPase is in charge of making the acid that is needed. There are a total of 14 components that fit together in order to function. A protein called VMA21 puts all the parts together. The researchers have found the gene that encodes VMA21.
Humans have to have VMA21 to survive. Some people have mutations in the gene that codes for VMA21 that reduce the levels of the protein without eliminating it completely. While people with the mutations can make the acid-making device it’s not made in qualities that are sufficient.
Because there are fewer acid-making devices there is less acid in the autophagosomes. When this happens the cells go on a major fast. The patient with the mutations start to live in near-starvation mode to survive.
While most organs are able to survive this loss the muscles cannot cope. This results in muscles that waste away and muscular dystrophy.
Sick Kids reports:
“To cure XMEA, we are looking for ways to increase the acidity of the autophagosomes,” says Dr. Berge Minassian, SickKids neurologist and Scientist, Associate Professor of Paediatrics at the University of Toronto and Canada Research Chair in Pediatric Neurogenetics. “As well, we hope to uncover the precise mechanisms in other vacuolar diseases – diseases whose cause is currently unknown and are characterized by expanded debris-containing structures.”
“This is a groundbreaking discovery that we hope will lead to finding a cure for XMEA and other forms of muscular dystrophy,” says Dr. Berge Minassian.
At this time there are 24 authors and 10 institutions in six countries, France, Japan, Finland, Italy, United States and Canada, working on this research.