Researchers at the Montreal Neurological Institute and Hospital (The Neuro), McGill University have discovered a genetic mutation underlying late-onset Leigh syndrome, a rare inherited metabolic disorder characterized by the degeneration of the central nervous system.
The study published in Nature Genetics, provides vital insights into the cell biology of this neurological disorder and will lead to the development of diagnostic and predictive tests allowing for family and genetic counseling.
Leigh syndrome usually begins in early childhood and is caused by genetic mutations which result in mitochondrial dysfunction. Mitochondria are compartments in the cell which have their own DNA and function to supply energy to the body. Damage and dysfunction to mitochondrial DNA is a factor in more than 40 types of metabolic diseases and disorders, including Leigh syndrome. The first signs of the disorder are often poor sucking ability, loss of head control, and loss of acquired motor skills or movement. As the disorder progresses, symptoms may also include generalized weakness, lack of muscle tone, episodes of lactic acidosis (the body becomes more acidic than normal) and breathing problems. Death usually occurs within a few years. In rare cases, "late onset" Leigh syndrome begins during adolescence or early adulthood and progresses more slowly than the classical form. Currently, there is no cure and treatment is limited and not very effective.
"Defects in the protein production machinery, or translation, are among the most common causes of mitochondrial disease," says Dr. Eric Shoubridge, neuroscientist at The Neuro and lead investigator in the study, "and the mechanisms that regulate translation have until now remained largely unknown."