Rare Disease Day is observed each year on the last day of February to shed a light on thousands of obscure conditions that affect patients around the world.

Rare Disease Day was first launched in 2008 in Europe by Eurodis, a non-governmental alliance of rare disease patients' organisations, to make policy makers and the general public more aware of the challenges faced by rare disease sufferers and their families.

This year's theme is research. With many events taking place around the globe, the tagline of this year's campaign is "with research, possibilities are limitless" – drawing attention to the fact that more research is urgently needed to help patients.

What is a rare disease?

Also known under the name "orphan disease", the definition of a rare disease varies from one country to the next.

In the US for instance, a disease is considered rare when 200,000 Americans or fewer suffer from it at any given time – that's one in 160 people. In Europe, "rare diseases" refer to any condition that affects 1 in 2,000 persons.

In both cases however, a rare disease affects a proportion of the population so small that very little is known about it and very little research is carried out to find treatments. This means that patients face significant hurdles to receive appropriate care and support.

Facts about rare diseases

Rare diseases affect between 25-30 million people in the US (about 1 American in 10) and approximately 30 million people in the European Union (3.5 million in the UK). About half of the individuals suffering from these conditions are children.

Rare disease Day is held each year at the end of February. Rare Disease Day

The term "rare disease" covers a wide range of disorders with very diverse symptoms.

To name but a few : lymphocytic leukemia, cystic fibrosis (characterised by an obstruction of the lungs by mucus), Duchenne muscular dystrophy ( a degeneration of the muscles) , microcephaly (an abnormally small head), Tourette's syndrome (a neurological disorder).

Globally, more than 6,000 diseases can be classified as "rare". However, the number of person affected vary greatly from one disease to another.

For instance, in the case of about 50 of rare diseases, thousands of patients are affected. In contrast, in the case of around 500 diseases, only a couple hundreds patients are diagnosed.

As much as 80% of those diseases could be caused by genetic factors. Around 65% are considered to be very serious and can cause the person to lose all autonomy.

Why more research is needed

With its tagline the 2017 campaign highlight one of the most important challenges that patients face – a lack of research focusing on their disease and, thus, a lack of therapeutic options.

Additionally, little research means incomplete scientific knowledge about the causes and symptoms of these diseases and this often leads to a delay in diagnosis. Because many symptoms can be confused with that of other illnesses, people are also often misdiagnosed.

Because of the scarcity and diversity of rare diseases, research efforts need to focus on bringing together scientists from around the world to share their data on patients.

"Research needs to be international to ensure that experts, researchers and clinicians are connected, that clinical trials are multinational and that patients can benefit from the pooling of resources across borders", campaigners point out on their website.

What is possible

A recent study, published in Disease Models & Mechanisms by a group of researchers from Pakistan, Europe and Singapore is an example of what is possible when scientists decide to work together. Working closely in collaboration, they have identified and characterised a previously undiscovered rare deafness-dystonia syndrome in a family living in a remote region of Pakistan.

Five of the eight children they studied had developed a hearing impairment at the age of six months which ended in profound deafness by 10 years old. Delayed motor development and subsequent regression were also observed. It has been named as "Siddiqi syndrome" for Dr Saima Siddiqi from Pakistan who first met the family.

With genetic sequencing, the team was able to identify a single homozygous nonsense mutation in the gene coding for a protein known as FITM2 – it is involved in lipid droplet formation and energy metabolism. This is the first step to finding drug targets and treatments for the disease and it raises new hopes that the patients will be able to receive appropriate care in the future.