The main aim of the study is to test a relatively new medical technology called Whole Body Magnetic Resonance Imaging (MRI), in patients with these syndromes, to see if cancers can be detected at an early stage which may, in turn, allow for more effective treatment. The investigators have chosen Whole Body MRI scanning because this scan allows doctors to look at the entire body in one examination. By using this technology, participants are not exposed to radiation, which is of particular importance for individuals who have a higher cancer risk due to a diagnosis of LFS.