Charcot–Marie–Tooth disease in Northern England: Figure 1

Charcot–Marie–Tooth disease (CMT) is a group of inherited disorders of the peripheral nerves.1 Clinical diagnosis of CMT can be made fairly accurately, and the clinical classification is very helpful in the identification of new disease genes. Thus far, approximately 40 genes have been implicated in CMT, but at present only a limited number of genes can be routinely tested worldwide, including the UK (http://www.ukgtn.nhs.uk/). All types of CMT are thought to affect approximately 5–40 per 100 000 individuals.2 A previous epidemiological study in the northeast of England in 1978 identified a lower point prevalence of CMT of 4.9 per 100 000.3 We re-evaluated the prevalence of CMT in this region, and report prevalence data for hereditary neuropathy with liability to pressure palsies (HNPP) in Northern England for the first time. The population of Northern England (Northumberland, Durham, Cumbria, parts of Yorkshire and Lancashire) is estimated at 2.99 million people with 259 500 in Newcastle upon Tyne, based on the 2001 UK census (Office of National Statistics; http://www.ons.gov.uk/). The Northern Genetics Service is defined by the boundaries of primary care trusts (online supplementary material) and the Newcastle upon Tyne Hospitals Foundation Trust. We identified patients in the Northern region who were alive on the prevalence day (1 September 2010) and had a clinical diagnosis of CMT through three prospective databases curated …