What are rare diseases?
A disease is defined as “rare” when its prevalence, meaning the number of cases observed in a given population, does not exceed a certain threshold, which in Europe is set at 0.05%, or no more than one case per 2,000 people.
Currently, about 10,000 rare diseases are known and diagnosed. However, thanks to continuous scientific progress, particularly in the field of genetic research, this number is constantly increasing. It is estimated that approximately 70% of rare diseases are caused by a genetic mutation, while the remaining 30% are due to infections, allergies, degenerative diseases, and proliferative diseases (tumors).
Causes of rare diseases
There are several processes that can lead to the onset of a rare disease. These are:
- Genetic mutations: A genetic mutation is a stable change in the DNA sequence of a particular gene, which is responsible for encoding a specific protein.
- Chromosomal alterations: A chromosomal alteration is a stable anomaly of a chromosome, the DNA-protein structure containing an organism’s genetic material. Chromosomes contain multiple genes, so chromosomal alterations lead to changes in multiple gene sequences.
- Infectious agents: The most common are bacteria, viruses, fungi, and parasites. Diseases caused by these agents are known as rare infections.
- Degenerative processes: The loss of normal anatomy or histology of an organ or tissue.
- Neoplastic proliferative processes: Diseases caused by the excessive and uncontrolled growth of certain cells in a tissue or organ, similar to cancerous mechanisms.
Challenges of a rare diseases
For many years, rare diseases have posed significant challenges due to the difficulty doctors (both general practitioners and specialists) face in providing an accurate diagnosis. This makes it impossible to develop an effective therapeutic plan (if one exists) that can truly help treat the disease or at least alleviate its symptoms.
As previously mentioned, most rare diseases are caused by genetic defects, which cannot yet be repaired. Therefore, a definitive cure for these conditions is not possible.
Another challenge lies in the development of treatments, which is why they are often called “orphan drugs.” Generally, unless specific incentives are provided, pharmaceutical companies are not interested in developing these treatments, as they cater to a limited number of patients and generate a negative economic return. For this reason, treatments are often expensive and, in many cases, not even available in certain countries. Due to these factors, rare diseases are often debilitating, chronic, or permanent, and can lead to fatal consequences.
Some data
Despite the term “rare,” these diseases are more common than one might think. Approximately 300 million people worldwide suffer from a rare disease, including 30 million in Europe and 2 million in Italy. Among these patients, about 70% are under the age of 14, and sadly, 30% do not reach their fifth birthday. Rare diseases are responsible for 35% of infant deaths within the first year of life.
According to the “Kakkis Every Life Foundation,” 95% of rare diseases do not have an FDA-approved drug, and for 50% of these conditions, no foundation is dedicated to developing appropriate treatments.
Examples of rare diseases
- Osteogenesis Imperfecta: Caused by mutations in genes responsible for collagen production, a crucial protein for bone structure. It results in bone fragility and a high tendency for fractures. It affects one newborn per 15,000–20,000 births.
- Allergic Angiitis: A rare disease caused by an allergic reaction. It leads to vasculitis (inflammation) of small and medium-sized blood vessels, initially affecting the respiratory tract and presenting symptoms similar to a common allergy (asthma and allergic rhinitis). It can be fatal if it affects the blood vessels supplying the heart. It affects 1–9 people per 100,000.
- Tongue Cancer: A neoplastic disease affecting 10 people per 100,000 annually in Europe. Its causes are still unknown, but alcohol and tobacco abuse are believed to be key factors.
- Smallpox: A rare, highly lethal disease caused by a viral infectious agent.
- ALS (Amyotrophic Lateral Sclerosis): A degenerative disease that affects motor neurons in the central nervous system, leading to difficulties in breathing, walking, speaking, swallowing, and moving. It affects 1–2 people per 100,000 and is an extremely severe disease with a fatal outcome.
- Trisomy 13: A disease caused by chromosomal alteration; it is characterized by the presence of three copies instead of the usual two of chromosome 13, even at the embryonic stage. It is a severe condition that often leads to death before birth or within the first seven days of life. It affects one newborn per 12,000.
Progeria, the disease at the center of our project, is also classified as a rare disease. Our choice was not random: we strongly believe that research in this often-neglected field is of utmost importance. Every step forward in understanding even one of these rare diseases can lead to new discoveries that benefit not only those directly affected but also medicine and biology as a whole. Through this project, we have the opportunity to bring this topic to an international stage, iGEM, and we hope to inspire many future researchers.