This is an MRC funded single centre, phase II, double-blinded, randomised control drug trial. It will be conducted at the University Hospital Birmingham and the University of Birmingham will act as Sponsor. Eligible participants will be randomly assigned to AZD4017 or a placebo ('dummy' with no active drug) for 3 months with a follow up a month later. Investigations during the study will include bloods, urine samples, pregnancy tests, lumbar punctures, DXA scans and small fat/skin biopsies. Participants will benefit from increased monitoring and a potential improvement in their condition.