Aiming for treatment they have spent more than 30 years describing, understanding and diagnosing the most common hereditary form of stroke, CADASIL. For this, the four French neuroscientists (from Paris Diderot and Paris Descartes) are now receiving the world’s most valuable prize for brain research – the Lundbeck Foundation Brain Prize, worth 1 million euros.
Each year 17 million people worldwide suffer a stroke. Around 30 percent of these are mini strokes caused by changes in the small vessels of the brain. To begin with, these strokes cause temporary symptoms such as weakness, numbness and impaired coordination. However, they tend to relapse, and since each new mini stroke affects the brain’s function, depression, concentration difficulties and dementia often follow in their wake.
In 1976, Professor Marie-Germaine Bousser was consulted by a middle-aged man who had suffered a minor stroke and showed clear signs of rapidly progressing dementia. His disease presentation was highly unusual, and less than 10 years later, the patient’s offspring developed similar symptoms.
Professor Bousser realised that this had to be a hereditary disorder, as yet undescribed. In order to solve this conumdrum she took the initiative to collaborate with colleagues at Lariboisière Hospital from Greater Paris University Hospitals /AP-HP, Inserm and Paris Diderot University : Professor Hugues Chabriat, Dr Anne Joutel and Professor Elisabeth Tournier-Lasserve. This working relationship would continue for more than 30 years.
The four scientists are now being awarded The Brain Prize, worth 1 million euros, for their comprehensive, in-depth and relentless research efforts. Together, they have solved the puzzle and shown that this is a hereditary disease, caused by a mutation in the NOTCH3 gene on chromosome 19. Mutations in this gene result in accumulation of protein in the walls of the small blood vessels. The changes occur throughout the body but only cause symptoms from the brain. The disease is hereditary, and children of mutation carriers have a 50% risk of inheriting the disease, which is known as CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy). The team has developed a diagnostic test and is involved in testing a potential treatment in animal models.