Rare diseases, the number of which is estimated at between 6,000 and 8,000, affect 1 in 2,000 French people. The FDA, the American drug agency, predicts that 40 gene therapy drugs will be on the market by 2022. “Our mission is to provide treatment for severe genetic diseases, which often affect children. From the start, it’s been our priority“, recalls Frédéric Revah, General Manager of Généthon.
Many advances have been possible thanks to the Telethon, in particular with gene therapy, which uses genes as medicine. This is a single administration intended to compensate for the deficiency of a diseased gene. For this, it is necessary to introduce a healthy gene, transported by a virus (vector) into the diseased cells. Researchers have succeeded in developing treatments for diseases that were previously thought to be incurable. Here are some examples.
Spinal muscular atrophy: an identified gene
In the cases of spinal muscular atrophy, blood collection from families and patients made it possible, from 1987, to analyze the DNA in question. A few years later, a team identified the gene responsible for the disease. Genethon scientists then worked on setting up a therapeutic strategy. “Gene therapy makes it possible to focus specifically on the mutated gene and replace it with a “piece” of non-mutated DNA. It must penetrate the nucleus of diseased cells“, summarizes Frédéric Revah.
“Our daughter Victoire is now 2 years old. At eight months and a week, the doctors diagnosed spinal muscular atrophy type 1. While her vital prognosis was two years, she was able to benefit from gene therapy thanks to donations from the Téléthon. This treatment – a one-hour injection – modifies the missing gene and stops the progression of the disease. Today, there is no more degeneration. Victoire is a curious and fulfilled little girl. She thwarted the predictions, she is still with us. She is sitting and holding her head. She is also learning four-legged. She is making progress every day. To accompany her on a daily basis, she benefits from sessions with a physiotherapist, a psychomotrician, an occupational therapist, and she also does balneotherapy. For the future, she dreams of going to school, playing sports like all the other little girls of her age.“, testifies Lætitia Hénin, mother of Victoire, two years old.
A pioneering discovery that allowed many others. And that is really the ambition of the Telethon: each project allows learning about other diseases. The larger the donations, the more the research saves lives.
Myotubular myopathy: first spectacular results
A revolution, the image of Jules whose life has changed thanks to this advanced science. The little boy, suffering from myotubular myopathy, was forced to permanently wear a respiratory device because of a mutation in the MTM1 gene.
Thanks to the Telethon, he received an injection intended to bring a healthy copy of the defective gene into his muscle cells on January 29, 2020. Ten months after the injection, the results were spectacular. Jules sat up, started eating alone, talking, etc. A second birth for the little boy.
Leber optic neuropathy: a drug awaits marketing authorization
Another challenge in which the Genethon teams took part: restoring the vision of patients suffering from Leber’s hereditary optic neuropathy. This genetic disease results from the anomaly of a mitochondrial gene which causes an alteration of the nerve cells composing the optic nerve. The disease is believed to cause blindness in approximately 1,400 to 1,500 people per year in the United States and Europe. Patients have been able to benefit from gene therapy treatment in clinical trials.
A real scientific feat since it involves correcting a localized anomaly in the mitochondria. This medicine is awaiting marketing authorization worldwide.
A new therapy for a rare liver disease
the Crigler-Najjar syndrome, a rare genetic liver disease, is characterized by the abnormal accumulation of bilirubin in all tissues of the body, and in particular in the brain. The accumulated bilirubin then causes intense and chronic jaundice that becomes toxic to the brain.
To maintain bilirubin levels below the toxicity threshold, there is currently only one solution: spend 10 to 12 hours a day under a UV lamp. In collaboration with Italian and Dutch teams, Généthon has developed a drug candidate which makes it possible to transfer a copy of the gene responsible for the disease. A clinical trial was conducted to assess its tolerance and define its optimal dose. The first results are encouraging.
How to donate to the Telethon?
In 2021, the AFM-Téléthon is supporting 40 trials in progress or in preparation on 31 rare diseases (vision, muscles, blood, etc.). To support the research, all you have to do is go on the Telethon.fr website and donate the amount of money you want.
You can also set up a direct debit. During the Telethon, you can make a donation by calling 36 37 or by visiting the website. Note, for example, that for a donation of 100 euros, 8.40 euros are used for management costs, 10.70 euros for collection costs and 80.90 euros are dedicated to the fight against diseases (Cure missions, Helping and Communicating).
Our expert : Frédéric Revah, general manager of Généthon (Telethon laboratory)
