Hemangiomas (from our understanding from the largest publications) occur in about 3-4% of the population. There is a huge difference in prognosis and need for treatment and response to treatment from where it occurs. We don’t know who it happens in or why it happens. In general, there are a couple of syndromes that are more likely to have hemangiomas. There are many that are more likely to have port-wine stains such as Sturge-Weber. In general, we don’t know what causes hemangiomas themselves or which mutation would cause them.