Núria Noel
Núria Noel
Project manager in Sant Joan de Déu

Why is understanding the natural history of a disease so important?

Natural history of a disease
Some diseases are so rare that their natural history has not even been described. These pathologies are practically unknown. But, why do experts insist on knowing in depth the natural history of diseases? What benefits can this bring to patients? In this article we explain it to you using clear examples and a lay language.

We are currently in the middle of a global pandemic caused by the new SARS-CoV-2 coronavirus, which causes a disease (COVID-19) that was completely unknown a few months ago, even to the medical and scientific community. Little by little, scientists are getting to understand all the aspects of this virus and the disease it causes. How is it spread, what are the symptoms and who does it affect with more virulence are questions that have been answered as the virus spread throughout the globe and the infected cases increased. How does the virus cause the disease or what is its progress like after the acute phase (what new symptoms or complications does it cause?) are other questions that are still unanswered.

Precisely, "the progression of a disease process in an individual over time, in the absence of treatment" is what the US CDC (Centers for Disease Control and Prevention) defined as the natural history of a disease. And, although there is no a unique description for this term, it is understood that it is the process that begins at the moment prior to the onset of the disease, going through its pre-symptomatic (before manifesting symptoms) and clinical (symptomatic) phases, until that the disease "is over". The latter may imply that the patient is cured, remains chronically disabled due to the disease or has died without external intervention.

The importance of understanding the process or natural history of a disease is based on the fact that, in theory, several factors (such as treatments) can be introduced during this process, with the aim of intervening and modifying the natural course of the disease. The interest of doctors and scientists in expanding knowledge about the course of a disease is important in the case of “new diseases” such as COVID-19, but also in the field of rare diseases, where there is a lack of medical data.


It is easy to imagine that the more cases of the same disease we describe, the more we will know about its natural history. And it is for different reasons. On the one hand, it will allow defining common characteristics for all the patients affected by the disease. And, on the other hand, the probability of seeing people affected in different stages of the disease will be greater, which will help doctors to differentiate and describe the differential features of each of these stages. Nor should we forget that “practice makes perfect” and to achieve perfection it is necessary to deal with many cases. Rare diseases affect very few people in the world and with these few cases the experience cannot be concentrated and unified, making it difficult for doctors to increase their knowledge on these pathologies.

Share4Rare has launched a research project to study the natural history of rare paediatric tumors

Paediatric cancers are considered ultra-rare diseases because of their low prevalence. Currently, there is a real need for research projects to increase knowledge about the natural history of these tumours, as well as to improve the management of these diseases and the quality of life of patients who suffer from them. For this reason, Share4Rare has designed the study A better understanding of Paediatric Rare Tumours, aimed at studying these cases in depth and analysing their characteristics and needs. In this research project we are seeking to collect data on the following oncological pathologies:

  • Gliomatosis cerebri
  • Xeroderma pigmentosum
  • Paediatric melanoma
  • Retinoblastoma
  • Rare pancreatic tumours
  • Vasculopathies

Very few cases of these types of children tumours have been described and, although we might think this is good news, it is precisely the low prevalence of these diseases that greatly obstructs improving their knowledge. COVID-19, however, has affected hundreds of thousands of people worldwide, and precisely that large number of patients will help to better understand the disease in the near future. At Share4Rare we work hard so this can also happen for peadiatric rare tumours. We want to break the barrier of what is “scarce" and help to prevent these diseases from being unknown, even if they are rare.

Related diseases
Giant congenital melanocytic nevus
Gliomatosis cerebri
Neuroendocrine pancreatic tumour
Paediatric melanoma
Parkes-Weber syndrome
PI3K related overgrowth syndrome (PROS)
Proteus syndrome
Solid pseudopapillar neoplasm of the pancreas
Sturge-Weber syndrome
Xeroderma pigmentosum