Why are rare diseases difficult to prevent and control?

February 28 is the 16th "International Rare Disease Day". This year's theme is "Light up Your Life", which aims to raise public awareness of rare diseases and rare disease groups, help rare disease patients receive timely diagnosis and intervention, and improve their quality of life.

So what are rare diseases and how to reduce their occurrence? Let’s talk about it today!

01. What is a rare disease?

Rare diseases, as the name suggests, are rare. Although there may be multiple factors causing them, in most cases, rare diseases are generally congenital diseases. According to the "China Rare Disease Research Report", it takes an average of 5.3 years and 2-3 misdiagnoses for rare disease patients to be diagnosed.

It should be pointed out here that congenital diseases are not necessarily diseases inherited from parents as everyone thinks. It is also possible that the parents themselves are fine, but the children have problems. Even the parents are not carriers of the disease. This is caused by random errors in the development process.

Therefore, a major problem with rare diseases is that they are difficult to prevent and control.

02. Why are rare diseases difficult to prevent and control?

Why are rare diseases difficult to prevent and control? Because the human body is constantly changing. Whether it is external factors, such as physical factors, chemical factors, or biological factors, or even without these factors, the body's own replication errors may lead to the occurrence of rare diseases.

For adults, because their development has basically stagnated, even if they are exposed to these mutations, they often do not cause major problems or are confined to limited areas.

But this is not the case for fetuses. They are in a rapid differentiation and proliferation process starting from 1. As a result, once a mutation occurs, it may continue to spread to more tissues and organs as cells proliferate.

Because of this, we will find that a lot of content, especially medical-related, is very concerned about infants and young children. For example, pregnant women are generally not allowed to be exposed to X-rays. Similarly, many medicines will also be marked "Use with caution in pregnant women". The reason behind this is the concern that the chemical components of the drugs will affect the fetus.

Because we cannot control the direction in which it mutates. Although organisms have repair mechanisms, we cannot control the direction in which the repair mechanisms go.

How big is the human genome? 3 billion base pairs , which means it is extremely difficult for us to study the consequences of a specific mutation. As a result, our current speculation and understanding of rare diseases are often based on limited cases.

Moreover, it often happens that mutations in multiple genes lead to the same consequence. For example, there are currently many speculations about ALS, such as SOD1, TDP-43 and KIF5A (kinesin family member 5A), which are all strongly related to ALS.

In short, rare diseases are currently confusing and you can hardly predict who will get a rare disease.

03. How to reduce the occurrence of rare diseases?

To reduce the occurrence of rare diseases, the only way at present may be prenatal genetic screening, which can compare genetic screening with known rare disease genes to avoid the birth of children with rare diseases.

Of course, there are some ideas to explore the treatment of rare diseases, such as gene editing, but these are still in the research stage.