By definition, a rare disease affects fewer than 1 in 2,000 people. 

That’s why they’re called ‘rare’. However, when we consider that there are 7,000 different types of rare disease affecting 300 million people (a number close to the population of the United States), perhaps they’re not so rare after all.

With these figures in mind, in 2025 the 194 member states of the World Health Organization (WHO) unanimously approved a historic resolution: a document that recognises these diseases as a global health priority and establishes a 10-year action plan. The goal? To incorporate them into national agendas, increase investment in research and promote the sharing of data between countries.

If we could perceive it, what sound would ageing make? What notes would represent the changes in shape, structure and colour that occur over the years? And, conversely, what signals would our body emit if it were capable of reversing that process?

Perhaps such a sound exists but we’re simply not capable of hearing it. Something similar occurs in our latest Snapshot of the Month. As if we were experiencing sensory synaesthesia, the scientific image in question awakens seemingly unconnected or even contradictory sensations: a changing stillness or a deafening silence. And the discovery behind it is no less disconcerting: it reveals a key mechanism involved in the ageing,

We ask the experts, Guadalupe Sabio and Beatriz Cicuéndez: How can we approach weight from a scientific view?

A new year has begun and, with it, new (or renewed) resolutions. Perhaps to take up a new hobby? Join a gym? Go on a diet to lose a few kilos? In any case, it’s common for our weight to figure prominently in a lot of these proposals, as indeed it has in many headlines recently.

Ozempic, Mounjaro, Wegovy… The emergence of new drugs that promise rapid, almost miraculous weight loss has once again placed weight at the centre of social debate, from the press to social media and everyday conversations. But what if we look beyond the number shown by the scales and take this issue to the lab?

Every five minutes, someone in the world is diagnosed with multiple sclerosis (MS). This disease affects more than 2.8 million people worldwide, including 55,000 in Spain. It usually appears between the ages of 20 and 40 (being the second leading cause of disability among young people) and three out of every four sufferers are women.

MS is an neurodegenerative disease of autoimmune origin that affects the brain and spinal cord. It occurs when the immune system mistakenly attacks the protective layer of neurons (called the myelin) and their axons (the part that connects them to other nerve cells). When this insulating layer and part of the neurons are damaged, communication between the brain and the rest of the body is interrupted,

Meningitis is a serious infectious disease that inflames the membranes protecting the brain and spinal cord, called meninges. Detecting the disease in its early stages is essential to prevent its most severe forms, which can even lead to death. However, the current diagnostic method, a lumbar puncture, is invasive and particularly complicated with infants, who often present with very non-specific symptoms. Furthermore, lumbar punctures to diagnose meningitis are costly tests that require a high level of specialisation and resources. As a result, they are performed less frequently in low- and middle-income countries.

Is there a way to improve and facilitate the diagnosis of meningitis? Sara Ajanovic, a paediatrician and researcher at ISGlobal and Vall d’Hebron Hospital,