Patricia Maroño

Patricia Maroño

Marketing Assistant

World Rare Disease Day

Today, February 29, World Rare Disease Day is celebrated under the slogan "Prevention is better than cure for rare diseases".

For a pathology to be classified as a rare disease (RDD), it must affect a certain number of people. In this sense, there is no worldwide agreement on what the prevalence should be, but in Europe, RRD is defined as affecting less than 1 in every 2,000 inhabitants.

Approximately 80% of RRDs are genetic in origin, while the remaining 20% are the result of infectious, immunological, degenerative or proliferative diseases. The most important problem faced by patients and their families is the delay in diagnosis. The data indicate that half of the patients wait more than four years for diagnosis, and in 20% of cases it can even take more than a decade. This time will depend on two variables: how clear the patient's signs and symptoms are and the degree of knowledge about the disease in question.

In order to understand this delay, it must be taken into account that 2 out of 3 cases appear in the first years of life, which complicates the correct diagnosis, since during childhood the signs and symptoms usually present in a poorly defined manner, in addition to the great variability that patients can show in their symptoms. This situation highlights the need for specific studies to identify the cause of RRD and, therefore, reduce the time needed to reach a diagnosis. The problem of diagnostic delay is compounded by the fact that only 5% are treated.

Characteristics and diagnosis

Most of the RRDs are chronic and degenerative diseases, so patients suffering from them face chronic pain, motor, sensory or intellectual difficulties, which cause physical, intellectual, vision or hearing disabilities, among others. All this translates into an impact on their quality of life and also, in parallel, on the lives of the people around them, who have to face added difficulties in their daily lives.

Leyre Larzabal, Clinical Genetics Manager

Since 80% of RRDs have a genetic basis, it is essential to perform a genetic study to try to obtain additional information that will help clinicians in the correct management of the disease. The process consists of obtaining a biological sample from the patient, usually blood or saliva, which is sent to the laboratory, where the DNA is extracted. This DNA is sequenced and a complex bioinformatics analysis is carried out on this data to identify all the variants or changes in the DNA of the sample under study. Subsequently, the geneticists will be in charge of relating these changes to the clinical presentation of the patient to identify those that are the cause of the disease.

In certain situations, such as the presence of a heterogeneous and complex phenotype that raises suspicion of several genetic diseases or that does not correspond to any known genetic disease, current technology allows the simultaneous analysis of the more than 20,000 genes present in humans, called whole exome study, or even the analysis of the entire genome as a whole. In pediatric cases, it will often be necessary to use a different approach called exome trio, in which samples from the patient and his or her parents are sequenced and analyzed. This approach has been shown to improve the diagnostic performance of the patient's genetic study in isolation.

In Dreamgenics we collaborate with some EERR associations, as is the case of the Association of Neuromuscular Diseases of the Principality of Asturias (ASEMPA), the Tarlov Cysts Association y Objetivo DiagnósticoIn this way they can better understand how these studies can help to correctly diagnose their disease and the implication that the information obtained has, both for them and for their relatives.

If you are a patient or an association, and you want us to help you, you can contact us by writing an email to or by calling 613 031 849 to speak with our geneticist Leyre Larzabal.

Interested? Subscribe to our newsletter