Lack of awareness of rare diseases in adults It remains a reality for a large part of the population, even though, collectively, they affect millions of people worldwide and several million in Spain alone. These are rare diseases with highly diverse symptoms that can drastically impact daily life, work, personal relationships, and the finances of families living with them.
Between 6% and 8% of the world's population Many people have one of these conditions; although each rare disease affects only a small group of people, collectively they represent a genuine public health problem. In Spain, it is estimated that nearly three million people are affected. Despite this, social ignorance, delayed diagnosis, a lack of specific treatments, and an enormous emotional and financial burden for patients and caregivers persist.
What is considered a rare disease and how many exist?
Less than 1 in every 2.000 inhabitants This is the standard definition in Europe for considering a disease rare. Some sources use very similar figures, such as fewer than 5 people per 10.000. Although the threshold varies slightly depending on the country or organization, the idea is the same: these are diseases that appear in a very small number of people compared to the total population.
Between 5.000 and 8.000 pathologies Many of these diseases are currently considered rare, and international organizations already report more than 7.000 well-described ones. The number of described rare diseases continues to grow thanks to improvements in diagnostic techniques and genetic research.
Around 70-80% have a genetic originIt is estimated that most cases are due to alterations in one or more genes, either inherited or resulting from new mutations. The rest may be related to immunological or environmental factors, infections, or mechanisms that are still poorly understood. In many cases, the underlying process remains unclear.
Approximately two-thirds debut in childhoodHowever, a significant percentage of people reach adulthood without a clear diagnosis or with a disease that manifests late, which further complicates its detection and treatment within the usual health circuits.
It is estimated that around 350 million people In the world, people could live with one of these pathologies; in countries like Spain or Chile, the global figures are impressive: in our environment it is estimated that more than three million people live with a rare disease, while in Chile it is said that around one million are affected.
Main characteristics of rare diseases
Low prevalence It is only the starting point; what truly marks the lives of patients is everything that stems from that rarity and the associated complexity.
Wide variety of symptoms This means that, even within the same disease, two people can show very different manifestations in severity, evolution and affected organs, which complicates the diagnosis.
About 1 in 5 patients People with rare diseases suffer persistent pain, and about half have some type of motor, sensory or intellectual limitation that compromises their autonomy.
More than 70% have a disability certificateMany of these women require approximately five hours of care daily, almost always provided by their families. This represents a physical, emotional, and financial burden that is rarely offset by available public resources.
More than 90% lack curative treatments And, in many cases, only symptomatic or supportive approaches are available, aimed at controlling complications and improving quality of life.
Fewer clinical trials and studies This is a direct consequence of its rarity: there is less accumulated experience among healthcare professionals, and this affects the development of effective therapeutic strategies and access to medicines.
Examples of common rare diseases in adults
Some diseases are relatively better known. because they have been disseminated in the media, awareness campaigns, or patient associations.
Amyotrophic lateral sclerosis (ALS) It is a neurodegenerative disease that causes a progressive loss of motor neurons; the prevalence is around 5-9 cases per 100.000 people and it usually appears between the ages of 40 and 60.
Marfan syndrome It is a hereditary connective tissue disorder that affects the skeleton, eyes, lungs, heart, and blood vessels, with a risk of cardiovascular complications such as aortic involvement.
hairy cell leukemiaHairy cell leukemia, also called hairy cell leukemia, is a subtype of chronic lymphoid leukemia that affects more men than women and is characterized by fatigue, frequent infections, and splenomegaly.
Cystic Fibrosis It is another disease with a significant presence in adults today thanks to advances in treatment that allow for greater survival and quality of life.
Myasthenia gravis and other rare neuromuscular disorders require specialized attention and a careful rehabilitation approach.
Some particularly striking rare diseases
There are extremely rare syndromes that attract attention due to their unique clinical manifestations and, sometimes, their medical history.
Fragile X syndrome It is one of the most frequent hereditary causes of intellectual disability and is due to an alteration in the X chromosome.
Moebius syndrome It causes facial paralysis and limitation of lateral eye movement due to involvement of cranial nerves VI and VII, which hinders expression and communication.
Prader-Willi syndrome It is characterized by hypotonia, developmental delay, obsession with food, and a tendency towards obesity that requires multidisciplinary follow-up.
Hutchinson-Gilford progeria It is a syndrome of accelerated aging that carries a high risk of cardiovascular and cerebrovascular complications.
Congenital Insensitivity to Pain (CIP) It alters the perception of pain and temperature, increasing the risk of undetected trauma and injuries.
Gilles de la Tourette syndrome It is characterized by motor and vocal tics that can intensify in stressful situations and require psychological and social support.
Other rare syndromes: from childhood to adulthood
The orderly transition from pediatric to adult services This is a growing demand, as many childhood-onset syndromes reach adulthood and require adapted resources.
achondroplasia It is the most common type of dwarfism of genetic origin and requires follow-up in adulthood due to joint, spine and respiratory problems.
Bardet-Biedl syndrome It combines visual, endocrine, and morphological alterations, with renal and cardiac risk that requires close medical monitoring.
Phenylketonuria It is a metabolic disorder that, if detected by newborn screening and treated with a low phenylalanine diet, allows for a virtually normal life.
Angelman syndrome It causes developmental delays, balance problems, and significant speech difficulties, and many people require ongoing support into adulthood.
tuberous sclerosis It causes benign tumors in the brain and other organs and usually requires a multidisciplinary approach throughout life.
The challenge of diagnosis in adults
Many patients go through several consultations and tests. before obtaining a diagnosis, which often turns the search into a real odyssey.
The scarcity of information and specific studies This leads many professionals to not initially consider a rare disease, and the overlapping symptoms with common pathologies contribute to the diagnostic delay.
Gene sequencing and molecular studies They are becoming increasingly crucial for accurate diagnosis, although the genes responsible for approximately half of rare genetic diseases have only been identified.
The programs of newborn screening They have marked a turning point in pathologies such as phenylketonuria, allowing treatments to be initiated that change the prognosis when detected at birth.
The role of Primary Care It is fundamental in early detection: family doctors are usually the first point of contact and those who notice details that do not fit into usual patterns.
Social, economic and emotional impact
Schooling and access to employment These are areas particularly affected by the lack of resources and the general lack of knowledge about these diseases.
Stigma and isolation These are recurring problems that generate a need for psychosocial support and visibility.
The economic burden Between treatments, therapies and travel, plus the possible reduction in working hours of the main caregiver, it represents a high impact on the family economy.
Family support It is often a determining factor: more than 70% of people with rare diseases need help with basic activities, which can lead to emotional overload and extreme fatigue in caregivers.
Patient associations They offer information, support, and a collective voice to demand changes in public policies and health resources.
Research, orphan drugs and the future
Genetic sequencing technologies and personalized medicine They have opened new avenues of treatment and diagnosis for pathologies that were previously considered untreatable.
orphan drugs They receive regulatory incentives due to their high cost and small number of patients, although their development remains complex from a commercial point of view.
Access to these treatments remains unequal due to differences in funding, cost-effectiveness assessments and organization of health systems between countries and regions.
Reference centers and collaborative research networks They allow for grouping cases, sharing information, and designing robust clinical trials despite the small number of patients.
Training in medical genetics as a specialty and increased investment in R&D would help improve diagnosis and family counseling, progressively reducing the cost of sequencing techniques.
Awareness campaigns such as “Rare yes, present too” They seek to remind us that, although they are in the minority, these diseases deserve the same attention and resources as other more prevalent pathologies.
Understanding how rare diseases manifest in adults and what challenges they entail It allows us to look beyond the numbers and recognize the real impact these conditions have on the lives of millions of people. Behind every diagnosis lies a story of searching, of fighting against ignorance, and of demanding basic rights in diagnosis, treatment, research, and social support. The better we understand these conditions, the easier it will be to build a healthcare system and a society that truly meet the needs of those living with them.
