RIT1 and vascular anomaly: However, with a total of three cases in the cohorts of vascular anomaly patients studied by this consortium, they are evidently much less common than variants of MAP2K1 or KRAS. Considering the total number of AVMs sequenced and of AVMs harbouring a RIT1 mutation, we roughly estimate the prevalence of RIT1 mutations in AVMs at approximately 1 out of 30.