Medical Mystery

Name me a medical condition that affects 2% of the UK population, that has no NICE or SIGN guidance, that only offers only a partial screen and bloods on the NHS, that has only one medicine approved for treatment for the RCP, (which was never formally trialled, but was 'grandfathered by the FDA) and where doctors who attempt to give their patients other medications that work for them are reported by other doctors to the GMC.
Stuck? Watch this video or if you don't have time, here's the transcript.
Can anyone explain this?