RASA1 and hereditary hemorrhagic telangiectasia: Although the appearance and location of the cutaneous capillary malformations or telangiectases described in RASA1-related disorder/Capillary Malformation-AVM Syndrome (CM-AVM) are distinguishable from those in HHT, there is enough similarity that making the distinction can be difficult for clinicians without specific expertise in the identification of vascular malformations.