GP coding of pre-symptomatic Huntington’s disease (HD)

HD is an inherited neurodegenerative disorder. It is important to know how common it is to plan services. Available clinic based surveys done before the gene test for HD was available underestimate disease burden. However, our local service data suggests that the most recent UK study using GP codes (Evans et al, 2013) over-estimates disease prevalence. We hypothesise this is because unaffected family members have been coded as if affected. To inform service planning in the UK and worldwide, we propose to assess the accuracy of GP coding of HD to improve interpretation of our pre-publication local prevalence data.