Huntington’s disease, which causes degeneration in adulthood, generally between 30 and 50 years of age, is in fact present from the embryonic stage according to a new research.
Although rare, less than 200,000 cases per year in the US, Huntington’s disease is a genetic neurological disease that affects mostly people with European ancestry. Most people who carry the gene are asymptomatic. But the symptoms include involuntary jerking, muscle problems, impaired gait, etc..
French researchers have made an unprecedented discovery on the pathology: it would in fact be visible in the human body from the embryonic stage.
Huntington’s disease usually appears in adulthood, between 30 and 50 years of age. It is defined first by psychiatric disorders before moving on to motor and cognitive disorders. It then progressively worsens without current medicine having the means to cure it. It is caused by a mutation in a gene encoding a particular protein called huntingtin. This is the reason why, when cases are known in a family, it is possible to carry out a predictive genetic test.
The teams of Sandrine Humbert, Inserm research director at the Grenoble Institut des neurosciences, and Alexandra Durr, professor at Sorbonne University tried to understand what was happening upstream of the stage when adults develop symptoms. They have therefore studied human embryos, some with the inheritance of the disease and others, without.
The researchers realized that from the embryonic stage the carriers of the gene were distinguished from the others. The anomaly present at this time of development was confirmed by then studying mouse embryos. “This is the first time that abnormalities in brain development have been detected in this disease. In addition, these are relatively large and extensive although we are not yet able to determine their direct consequences ”, specify Sandrine Humbert and Alexandra Durr who led this work.
They tried, at this stage of the study, to explain why the disease was taking so long to develop: “We hypothesize that the brain very early sets up compensation mechanisms that allow normal functioning. It could also be the same in people with mutations associated with other types of degeneration such as Alzheimer’s disease or amyotrophic lateral sclerosis “.