RASopathies are a group of rare genetic conditions caused by mutations in genes of the Ras-MAPK pathway. Abnormalities of this pathway have profound effects on development and can cause one of several different syndromes, including:
- Cardio-Facio-Cutaneous syndrome (CFC)
- Costello syndrome (CS)
- Legius syndrome
- Neurofibromatosis type 1 (NF1)
- Noonan syndromess (NS)
- Noonan with Multiple Lentigines (NSML) (formerly called LEOPARD (LS)).
These syndromes share many clinical features in common with one another, such as distinct facial features, developmental delays, cardiac defects, growth delays, neurologic issues, and gastrointestinal difficulties. While these individual syndromes are rare, as a group, the RASopathies are among the most common genetic conditions in the world.