Dr Melanie: Living with a rare disease

Great support can be found if you know where to look

Rare diseases each affect fewer than one in 2,000 people, but there are around 8,000 of them, with more being discovered each week. That means over 3 million people in the UK currently live with one, and one in 17 of us will develop one during our lifetimes.

Some are quite well-known – like the respiratory disorder cystic fibrosis (with over 10,000 people on the UK Registry) and Huntington’s disease, a degenerative, neurological condition thought to affect over 5,000 UK adults. But the general public has never heard of most rare diseases and some only affect tiny numbers.

What causes these diseases?

Three-quarters start in childhood, and four out of five have a genetic link. There could be a single abnormal gene that may be dominant (so that if you get it from either parent, you get the disease – for example, in Huntington’s) or recessive (where you get an abnormal gene from both parents – for example, in cystic fibrosis).

Some rare diseases are the result of a chromosomal abnormality, and some such abnormalities, like that which causes Down’s syndrome, can be tested for in early pregnancy.

Other diseases may be triggered by environmental factors, such as infections and allergies, degenerative changes, deficiencies or toxins. The devastating effects of the drug thalidomide, for example, which was commonly prescribed for pregnancy sickness in the late 50s and early 60s, are well documented. Low folic-acid levels in early pregnancy can result in spina bidifa in the baby.

What problems can they cause?

If you have a rare disease, even your doctor may know little or nothing about it. In fact, in one survey, 40% of people said they’d had difficulty getting diagnosed. There’s little information on the internet, and research or treatment

funding is usually limited. Being diagnosed can bring its own problems, too: uncertainty about the disease; what and how to tell family and friends; interactions with other medical conditions; difficulties with work, insurances and benefits, and deciding whether or not to have children.

On the other hand, because heart disease, diabetes, cancer and so on affect so many, we know a lot about them: causes; if they’re inherited; how they affect body cells; symptoms; how to diagnose and monitor them, and the lifestyle changes and treatments that work best.

Numbers also mean the NHS funds specialist services for these conditions, drug companies will research potentially profitable new treatments, and there are many charities and support groups.

Some progress

In 2013, the Department of Health & Social Care launched the UK Strategy for Rare Diseases, aimed at improving awareness, diagnosis, research, resources and care pathways, and empowering patients.

This has included antenatal screening and cascade testing (looking for affected relatives), the 100,000 Genomes

Project (50,000 volunteers’ genetic blueprints analysed so far), the UK Genetic

Testing Network (a worldleading nationwide network of 13 NHS Genomic Medicine Centres) and a Patient Empowerment Group.