Public Health, Rare Disease

Rare Diseases


What is a rare disease?

According to the European Union, rare diseases are classified as one that affects less than 5 in 10,000 of the general population. Similarly, the NIH defines it as: ‘one that affects fewer than 200,000 people’. This means that it’s possible that most people aren’t aware that rare diseases exist unless it affects them personally.  Moreover, if we consider that the world is made up of 7 billion people, these rare diseases don’t seem so rare after all. 

It is estimated that up to 25 – 30 million Americans are affected by rare diseases. Similarly, it’s said that 3.5 million people in the UK and 30 million people in Europe are already/will be affected by rare diseases. 


What causes rare diseases?

While the exact cause of rare diseases are unknown, most (around 80%) are classified as genetic disorder. They arise due to changes or mutations in genes. Often rare disease are generational meaning that they’re hereditary (and will affect more than one member in the family). There are also environmental factors at hand such as diet, smoking and chemical exposure. 

Some examples of rare diseases include:

  • Rare mitochondrial disease
  • Cystic fibrosis
  • Muscular dystrophy
  • Huntington disease

There are different types of rare diseases:


How are they treated?


There are more than 7000 rare diseases and while many of them can be diagnosed using biological sample tests, only 5% have treatment specifically tailored to them. The other 95% do not have approved treatments.

Instead, the majority of rare diseases are treated using medication that only affects the symptoms and not the cause. This is what is known as symptomatic treatment. Additionally, medications used for other conditions can be re-used to treat different rare diseases.

One major area of concern regarding rare disease is that often patients receive inadequate treatment or a delay in diagnosis. This is because not enough doctors have the know-how to deal with these conditions. Therefore, it is extremely important that the biomedical community continues to invest in research on rare diseases to insure that patients receive the best possible care.

Currently, curing rare diseases involves the use of stem cells, organ transplants and finding a suitable donor – all of which are extremely difficult to facilitate. The cost of treating rare disease is extremely high, but researchers are continuing on with the search.

What does the future hold?

In the past few years, gene therapy has been tested as treatment method, but there is hesitation due to the lack of profitability and how difficult it is to proceed from trial phases to marketing. 

There has been some success for several rare diseases using gene therapy leading to approval of some drugs for the market. However, researchers will most likely focus on more prominent rare diseases in order to get their drugs on the market. Large pharmaceutical companies and health bodies are unlikely to pay the high costs of medications for less prominent diseases meaning that there’s a huge disparity between the progress made with some rare diseases compared to others.

There is some hope for the future, though. Over the past few years there has been a great advance in CRISPR/Cas technology. CRISPR/Cas is a gene editing tool used for genetic engineering. Genetic engineering is the process in which the genetic structure of an organism is modified. DNA is either inserted, deleted, altered or replaced in the genome of a living organism. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) enables researchers to change DNA sequences and gene function while cas9 is an enzyme that acts like scissors and cuts DNA.

It’s hoped that CRISPR/Cas will be used to remove the DNA sequences that contain the mutations/alterations that cause most rare diseases.

How can people help?


There are many different ways that people can help those with rare diseases – the main one being raising awareness.

This can be done via social media; people can share stories, information and data and try to reach as many readers and listeners as possible. Awareness days are held each year, some for specific disease and more mainstream campaigns like Rare Disease Day (which is being held on February 29th 2020). People can also join organisations and arrange various activities in order to raise awareness about rare diseases.


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