Mosaic RASopathies

Mosaic RASopathies are a group of developmental syndromes with highly variable phenotypes typically involving the skin, eyes, brain, and cardiovascular and/or skeletal systems caused by mosaic mutations in the genes of the RAS/MAPK pathway. The degree of organ involvement and the extent of disease are dependent on multiple variables, including the timing of the post-zygotic mutation during embryogenesis, the affected cell lineages, and the extent of altered RAS/MAPK activation. Mosaic RASopathies and their molecular backgrounds are becoming increasingly recognized due to more widely available genetic testing as well as advances in sequencing technologies.