The 2026 Telethon fundraising campaign aims to reach around 100 million euros to support research on rare diseases. Over the past decades, the Telethon has transitioned from basic research to achieving significant therapeutic breakthroughs, notably in gene therapy. A prime example is the treatment for spinal muscular atrophy (SMA), which has saved many children's lives through early genetic screening and innovative therapies developed by the Telethon's Généthon laboratory. The campaign also funds clinical trials for Duchenne muscular dystrophy, sickle cell disease, and other conditions, with promising results such as improved motor functions and slowed disease progression. The funds are allocated to various missions, including 'Guérir' (Heal), which finances clinical trials, research laboratories, and patient support programs. Additionally, a third of the budget supports family assistance, training professionals, and providing respite care. The Telethon has already raised a total of 3 billion euros over 40 years, primarily during its annual mobilization weekend, with contributions from over four million donors. Recent achievements include the generalization of SMA newborn screening in France, early treatment options, and ongoing trials for other rare diseases. Despite these advances, critics highlight the need for increased efforts in early diagnosis and ethical considerations in genetic research. The campaign continues to emphasize transparency and the importance of collective effort in fighting rare diseases.