The cause for vascular malformations is usually sporadic (occurs by chance). However, they can also be inherited in a family as an autosomal dominant trait. Autosomal dominant means that one gene is necessary to express the condition, and the gene is passed from parent to child with a 50/50 risk for each pregnancy.
Males and females are equally affected and there is great variability in expression of the gene. Vascular malformations are a manifestation of many different genetic syndromes that have a variety of inheritance patterns and chances for reoccurrence, depending on the specific syndrome present.