Rare diseases, such as unusual hereditary conditions and some less common forms of cancer, affect many more people than most of us would imagine. In the EU, diseases are defined as rare if they afflict no more than five in 10,000 people. But put that in the context of more than 6,000 rare conditions so far identified and the total numbers affected - including the families of those that suffer from them - and we are well into the millions in the UK alone.
But, despite the millions of dollars spent worldwide on developing new therapeutic drugs, the treatments approved to tackle these rare conditions remain pathetically few. The biggest obstacle to improvement is money. Most drugs are licensed for use in conditions where the drug manufacturers are both able to recruit enough patients into clinical trials and where the products will yield enough sales to justify running those trials in the first place. So, people with rare diseases find their access to effective medication either limited or non-existent.
The first genetic condition ever identified, Alkaptonuria (or AKU) is a case in point. It's over a hundred years since AKU, more commonly known as black bone disease - for the discolouration and damage it causes to the bones and cartilage - was identified. Yet there has never been an effective treatment for it and people with AKU, who see the symptoms appear typically in their 20s and 30s, suffer chronic health problems that often lead to destruction of the cartilage and early joint replacement surgery.
A relatively small number of people with AKU have been identified in the UK (around 70) but experts, who describe the disease as a severe form of arthritis, to which it's closely linked, believe there's a much larger number who are living with AKU undiagnosed.
This month, the AKU Society - a small UK patient charity supporting those with the condition - launched a campaign to raise funds for a late-stage clinical trial of a drug that does promise a treatment for AKU. It could in turn give hope to some of the eight million in Britain who suffer from osteoarthritis, to which AKU is closely linked.
Dr Lakshminarayan Ranganath, co-founder of the AKU Society and one of the country's leading experts on the condition, says "Anything we can do to understand AKU will undoubtedly help us to understand other forms of arthritis."
The drug nitisinone, which is already marketed for another hereditary condition has been shown in previous clinical trials to relieve AKU patients' symptoms but because of the estimated £5m costs of mounting a late-stage clinical trial and the relatively small patient population, no organisation has yet put up the funding.
Taking the drug over this final development hurdle would create the first ever treatment for AKU, as well as a better understanding of osteoarthritis and its potential treatment - a hugely significant benefit in an area of unmet medical need. Some well-funded organisation, ideally a pharmaceutical company, should put the money up for the trial. Research into rare conditions such as this one really shouldn't be left to charity.