How is a rare disease diagnosed?

What is a rare disease?

A rare disease is considered so for a matter of incidence , since it occurs in less than 1 case per 2,000 inhabitants . Although this estimate varies depending on the area, in the United States the ratio is 1/1,300 inhabitants, in Japan 1/2,500 inhabitants, and in Australia 1/15,000 inhabitants. For practical reasons, we will focus on the European Union criterion, which is applicable to our territory.

Rare diseases bring with them an additional problem, in addition to the symptomatology: the lack of treatment resources. Because these are very rare diseases, the amount allocated to drug research is substantially reduced. This creates even greater difficulties in all aspects of treatment. It is not surprising, therefore, that the diagnosis of a rare disease must be made as soon as possible.

On the other hand, a rare disease can be suffered, a priori , at any time in life, even before birth. The problem is that many of these conditions are genetic in origin, and the diagnosis is usually made during childhood.

But what happens when symptoms are barely perceptible, or when they only appear at a certain point? This is where diagnostic techniques come in to help pinpoint the problem as quickly as possible.

Diagnosis process of a rare disease

First of all, it's worth noting that not all rare diseases are genetic in origin; some are environmental, or share both factors. This is crucial when targeting potential treatments. That said, to confirm or rule out a particular disease, the process follows these steps: steps :

1. Initial consultation with a medical specialist

The first step is to go to a specialist to check if the symptomatology is compatible with a rare disease. If there is no history of it, you'll normally have previously seen a general practitioner. If there's any doubt or strong suspicion of having that disease, you'll move on to the next phase.

Since some rare diseases are silent in their initial stages, we recommend that you see a doctor as soon as possible. In many cases, quality of life can improve substantially with early diagnosis.

2. Identification of possible family history

The ID of possible family history It's a powerful indicator for comparing the incidence of rare diseases. This is something specialists often ask, but it's also a good idea to make them aware of it. This way, the detection process can be accelerated because more specific tests will be ordered.

It is clear to everyone that genetic inheritance has an importance that goes beyond external characteristics. Therefore, if a family member has suffered from a rare disease, the chances of are hereditary are tall.

3. Laboratory and imaging tests

Subsequently, they will be carried out laboratory tests to determine the severity of the problem beyond what is visible. Typically, blood, urine, and possibly stool tests will be performed; in more specific cases, amniotic fluid (prenatal) tests or biopsies may be performed. Other options include: Imaging tests , such as X-rays, CT scans, and mammograms, among others. With all this information, possible diagnoses will be much more specific.

We must emphasize, however, that these tests must be properly scheduled and supervised. In fact, depending on the type of rare disease, some tests will be prioritized over others; and this is important when it comes to making an accurate diagnosis.

4. Genetic testing

Genetic testing is the next phase of the process, and can be done prenatal, in children or adults. Here, there is already a strong suspicion; therefore, various options are used, depending on the case:

• Screening for monogenic diseases: When it comes to single-gene disorders, tests can be performed to see if there is a specific mutation in this case. There is also a microarray test, which performs this function. Obviously, there must first be sufficient evidence that this is the cause of the disease.
• Screening for chromosomal abnormalities: Chromosome testing allows us to see if there are any alterations or modifications. It's undoubtedly a way to rule out, but also to focus on if a problem is identified. Since there are numerous rare diseases based on chromosome abnormalities, it's common.
• Genetic compatibility test: Genetic compatibility testing is often used before conceiving to check whether the offspring are likely to suffer from any genetic diseases.
• Genome sequencing: Genome sequencing works because it can reveal several possible mutations that cause rare diseases. In this sense, it should be complemented by some type of query of genetic information databases.
• Genetic panel: Genetic panels allow you to check, using a selection of specific genes, whether they contain variations or mutations. They are used when a fairly precise range of possibilities has already been defined.

The great advantage of these tests is that they provide a very high, almost definitive, accuracy rate. Therefore, at this point, a diagnosis will be much easier to make.

5. Confirmation of the diagnosis of a rare disease

Finally, and in the context of clinical and genetic testing, a more accurate diagnosis . However, it is essential that, in the case of a rare disease, a specialist make the diagnosis. This way, the various clinical treatment options can be considered.

Let us also remember that the diagnosis can be  prenatal or even prior to conception. In the second case, we would be talking about probabilities, but it is a useful variable for making family planning decisions.

In summary…

Diagnosing a rare disease is the responsibility of a physician, but testing can be done to determine if there is a possibility. Genotics You'll find a complete list of laboratories, test types, prices, and delivery times for you to compare. Get to know us. better!