Characteristics of rare diseases
Rare Diseases
The modern health care system has made leaps and bounds in the past few decades. With the exponential growth of the system, people with illnesses can often go to the hospital expecting a diagnosis and proper treatment to follow. Unfortunately, there are thousands of known diseases, many of which are considered rare diseases.
A rare disease is defined as any disease that is not common. A rare disease usually has such a low prevalence in a population that doctors may have trouble diagnosing and treating the disease, being that they would likely only expect to see one case per year. Many of these rare diseases are genetic and, therefore, are present throughout the victim’s entire life. Many of these diseases do not show symptoms until later in life, and therefore are very hard to diagnose. Some rare diseases, however, appear early in life, affecting children. It is estimated that 30% of children suffering from a rare disease will die before reaching the age of 5.
There is no single definition of rare diseases, due to the many different systems of measurement around the world. For example, in the United States, a rare disease is defined as such only according to prevalence. If a disease affects less than 200,000 people in the United States, or 1 in every 1,500 people, it is considered rare. In Japan, the disease is only considered rare if its affects fewer than 50,000 patients, or 1 in every 2,500 people. The European Commission on Public Health defines them as life-threatening or debilitating illnesses that require combined efforts to address, due to their low prevalence.
The term orphan disease is often used interchangeably with rare disease in the United States due to the lack of treatment, lack of resources, and severity of the disease. Europe, however, distinguishes between rare diseases and neglected diseases in the category of orphan diseases.
The rest of this article will focus on some of their characteristics:
- They are usually genetic, and therefore chronic. There are an estimated 80% of rare diseases that are genetic. A genetic disease is usually very hard to diagnose, as symptoms often do not show until later on in life. In cases that are not genetic, infections and allergies may be the cause of illness.
- A disease’s rarity is dependent on the population that is being studied. For example, cancer is very rare in children, but some forms of cancer are very common amongst adults.
- In some rare diseases, symptoms may appear at birth or during childhood. Many others, however, only show symptoms when adulthood is reached, or even later.
- While many are chronic and incurable, there are short-term medical conditions that are also considered rare diseases.
- The European Organization for Rare Diseases estimates between 5,000 and 7,000 rare diseases. There substantial amount of individual rare diseases causes a relatively large percentage of the population (6-8%) to be infected by one.