Huntington's family discuss how they cope with disease
31 July 2013 Last updated at 13:18 BST
Rugby player Josh Cook is 22 years old and has been diagnosed with the Huntington's gene, which means he will develop the disease when he reaches his 50s.
It affects the nervous system and will eventually leave him severely disabled.
His mum has the gene as well and will also develop the disease.
Josh talks to his mother about how they deal with day to day life with the disease hanging over them.
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