We are ending the month of February, and this means that the Rare Disease Day is approaching. Marfan syndrome, Williams syndrome, DiGeorge syndrome, Crohn’s disease, Fanconi anaemia, mucopolysaccharidosis, among many others make up the list of these diseases. Why are they called minority diseases or rare diseases?
WHAT ARE MINORITY DISEASES?
A minority disease is that which affects less than 1 in 2,000 people. Although individually they are rare, there are many diseases of this type (6,000-7,000), so there are many affected patients.
Although the definition of minority disease is what I have just said, in the pharmaceutical industry it is that disease in which it is not profitable to develop a drug due to the low number of patients, the limited information available, the poor diagnosis, the lack of clinical studies and the difficult location of patients. It is for this reason that the families themselves create their own foundations to obtain financing for the investigation of these diseases.
A few years ago these diseases were socially forgotten, but, fortunately, they are now socially transcendental and recognized.
As I said, there are around 7,000 minority diseases described and every year between 150 and 250 new ones are described, thanks to new technologies.
A large number of these diseases affects children, that is, they manifest themselves at an early age. It is necessary to know that most have a genetic basis, caused by mutations in specific genes such as cystic fibrosis or several muscular dystrophies. But there are also related to environmental factors, such as some types of anaemia due to lack of vitamins or due to medications. This is the case of malignant mesothelioma, a breast cancer, in which more than 90% of cases are due to asbestos exposure. However, there are still many without knowing their origin or data on their prevalence.
MINORITY DISEASES IN NUMBERS
The fact that these diseases affect few people and the ignorance of their symptoms by the public and professionals, it is estimated that the time that elapses between the appearances of the first symptoms until diagnosis is 5 years. In 1 of every 5 cases, more than 10 years may pass until the correct diagnosis is obtained. This means not receiving support or treatment or receiving inadequate treatment and worsening the disease.
Not all hospitals have the means to treat those affected, for this reason it is estimated that practically half of sufferers have had to travel and travel in the last 2 years out of their province because of their illness, either in look for a diagnosis or treatment.
Minor diseases represent a significant economic cost. The cost of diagnosis and treatment accounts for around 20% of the annual income of each affected family. This means an average of more than 350€ per family per month, a figure very representative of the high cost involved in the care of rare diseases. The expenses to cover in the majority of cases are related to the acquisition of medicines and other health products, medical treatment, technical aids and orthopaedics, adapted transport, personal assistance and adaptation to housing.
TREATMENT FOR MINORITY DISEASES
Only 1-2% of minority diseases currently have some type of treatment, therefore, much remains to be investigated.
There are 4 basic types of treatment for rare genetic diseases:
PHARMACOLOGICAL THERAPIES
It consists in the modification of a normal or pathological biochemical reaction by an external chemical agent.
The development of a drug is a very expensive process and difficult to quantify. Currently many millions have to be invested for a new drug to reach the patient.
But what is a medication? A medicine is a small organic molecule, which typically has to be:
- Specific to solve a molecular problem (ex: prevent an abnormal interaction between two proteins)
- Very active and very tuned for your target
- Very little toxic
- Distribute well throughout the body and reach the target tissue
- Cheap to produce or, at least, that can be synthesized in industrial quantities
- Stable
- New (patentable)
- It has to be commercialized
GENE THERAPY
Attempt to correct defective genes responsible for diseases in the somatic (non-sexual) line, either by:
- Loss of function: incorporate the normal gene (ex: phenylketonuria)
- Function gain: eliminate the responsible mutation, eliminating the protein (ex: Huntington)
Limitations:
- Only the reversible characteristics of a genetic disease can be corrected
- The size of the DNA to be incorporated in the patient’s genome
- Immune response against the viral vector (retroviruses, adenoviruses, adenoassociates)
- Inactivation of an essential gene that can cause a problem greater than the disease
- Directionally to appropriate target cells
CELLULAR THERAPY
Describes the process of introducing new cells into an affected tissue, with or without previous gene therapy. It is necessary to introduce many cells because the treatment is effective and, sometimes, these cells can go to unwanted tissues or have some types of abnormal growth.
SURGERY
For example in congenital heart defects.
RARE DISEASE DAY
For rare diseases to cease to be, Rare Disease Day is celebrated on the last day of February, with the aim of raising awareness and awareness among the public about rare diseases; as well as showing the impact on patients’ lives and reinforcing their importance as a priority in public health.
It was established in 2008 because, according to the European Organization for Rare Diseases (EURORDIS), the treatment of many rare diseases is insufficient, as well as in social networks to support people with minority diseases and their families. In addition, while there were already many days devoted to people suffering from individual diseases (such as AIDS, cancer, etc.) before there was not a day to represent people suffering from minority diseases. It was chosen on 29th February because it is a “rare” day. But it is celebrated on the last day of February in years that are not leap years.
Then I leave the promotional video for the Rare Disease Day 2015:
Video 1. Rare Disease Day 2015 Official Video (Source: YouTube)
REFERENCES
All you need is Biology 
