Identification of the Molecular and/or Pathophysiological Bases of Rare Diseases of Genetic Origin (or Rare Forms of Frequent Diseases Suspected of Being of Genetic Origin).

Rare diseases are conditions affecting a small number of people, requiring specific and often multidisciplinary medical care. There are over 7,000 rare diseases, around 80% of which are genetic in origin. These diseases are generally severe, chronic and progressive, and can considerably affect the quality of life of sufferers. Although significant efforts in the search for genetic causes over the last two decades have led to the identification of thousands of genes associated with Mendelian diseases, half of all individuals with a rare disease remain without a genetic diagnosis. It is important to pursue the ambition of participating in the effort set by Europe, namely the identification of a large majority of the genetic causes responsible for rare diseases, and to be able to provide genetic counselling to patients and their families. In the past, scientific research to discover genes required a large number of families and individuals, and was long and costly to carry out. Today, this approach is facilitated by next-generation sequencing. When high-throughput sequencing (HTS) identifies candidate genes or genetic abnormalities, it may be necessary to propose functional analyses to try to reach a conclusion.