It is a genetic anomaly. There has been very little research into BWS because it is such a rare condition. The current research hasn't found any specific links to it. Some studies may link IVF, but these are not definitive and have small samples of patients. Hereditary cases are thought to be rare, but there isn't much study on this. Because BWS is also often missed or misdiagnosed, many people may be unaware they even have it. Further study is needed to give a solid outline on this syndrome.