In a little under a week I'll be trudging 26 miles around London raising money for the Alkaptonuria society.

Alkaptonuria (AKU) is a rare and little-known genetic condition, passed from parents having recessive genes to their children, if they're unlucky - only 25% of children whose parents both happen to have the recessive gene actually develop it. My son is one of the unlucky 1 in 250,000 people who has inherited AKU from me and Nicole.

Also known as black bone disease, sufferers are unable to process a specific acid which leads to its build-up in the body, leading to brittle bones and joints and early onset osteoarthritis.

The AKU Society provides support to sufferers and undertakes research for a cure. Given the rarity of the condition, they are not a large organisation and therefore rely on money from fundraising to support them, so anything you're able to give will make a real difference.