People with Huntington's disease often start to experience symptoms a number of years before the condition is actually diagnosed. This is particularly true in cases where someone is unaware that the condition runs in their family.
If you're showing features of Huntington's disease and it's known to run in your family, or if your doctor strongly suspects that you have the condition, genetic testing can be carried out to confirm the diagnosis.
It's important to realise that the diagnosis is based on the doctor recognising a combination of a number of factors – neurological examination, family history and genetic testing. It's possible to have the gene change and still be healthy. This is known as "premanifest Huntington's disease".