By Emma Innes PUBLISHED: 05:37 EST, 5 June 2013 | UPDATED: 05:49 EST, 5 June 2013 Two-year-old twin sisters are not able to enjoy playing in the park or to go on holiday because the excitement could kill them. Darcie and Evie Chapman, from Warrington, Cheshire, are the only twins in the UK to have a severe form of epilepsy called Dravet Syndrome. Seizures can lead to SUDEP (sudden unexplained death in epilepsy patients) and the condition leads to delays in development, feeding problems, sleep problems and behavioural problems. Evie and Darcie Chapman have a severe form of epilepsy called Dravet Syndrome. It causes seizures, developmental delays, behavioural problems and feeding difficulties. They are pictured with parents, Mark and Natalie
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Darcie and Evie Chapman, from Cheshire, both have Dravet Syndrome
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Their seizures can be triggered by excitement and extremes of temperature
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The syndrome also causes developmental delays and behavioural problems
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Their seizures are now successfully controlled using medication
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May be eligible for treatment with special high-fat diet when they are older
Ms Chapman, a project manager for a building company, explained: '@placeholder had a fit first.