 Until today, three case reports have described the successful use of the mTOR inhibitor Rapamycin for the therapy of patients with segmental overgrowth and PTEN germline mutation. The Investigator recently started with off label use of Rapamycin in these patients. First results with successfully treated patients have been presented at The Annual meeting of the German Society of Human Genetics in 2011 and the meeting of the International Society on the Studies of Vascular Anomalies in 2012. In one patient with segmental overgrowth syndrome and response to Rapamycin, the investigators could identify a PI3KCA mutation in one lesion. This case is currently prepared for publication. Interestingly, response on mTOR inhibition could be demonstrated in some patients although lack of mutation in the published genes responsible for overgrowth syndromes. 