On February 24, the Second Conference on Rare Diseases was held at the Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM) CSIC-UAM to commemorate Rare Disease Day, which takes place on February 28. Once again, this event highlighted the commitment of scientists to researching rare diseases, disseminating acquired knowledge, and providing all necessary support to patients and their families.
A disease is considered rare or uncommon when it affects fewer than 5 in 10,000 people. However, since there are approximately 7,000 different rare diseases, it is estimated that, collectively, they impact around 6% of the population, representing a significant global health burden and a high healthcare cost. These diseases pose a major challenge in medicine and research, as each has different causes and symptoms, requiring highly specialized medical expertise and scientific knowledge—something difficult to achieve given the limited number of patients compared to more common diseases. Between 70-80% of rare diseases have a genetic origin, with most caused by mutations in genes that encode proteins with little or no known function. As a result, securing resources to study the molecular and pathogenic bases of these diseases, develop new treatments, and explore potential cures is a considerable challenge.
For the second consecutive year, the Instituto de Investigaciones Biomédicas Sols-Morreale, through its Rare Diseases Department, has organized the II Rare Diseases Conference to raise awareness of the rare conditions studied at the IIBM. Last year, during the I Rare Diseases Conference, the speakers were researchers from the IIBM’s Rare Diseases Department. This year, however, four researchers from other IIBM departments who also work on rare diseases (Teresa Iglesias Vacas, Soledad Bárez López, Silvia Martín-Puig, and Isabel Lastres Becker) were invited, along with patient associations and clinical experts. Additionally, two external researchers were invited to open and close the event: Dr. Belén Pérez, a researcher at the Centro de Biología Molecular Severo Ochoa (CSIC-UAM), part of the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) and the Instituto de Investigación Biomédica del Hospital Universitario La Paz (IdiPAZ), as well as the deputy director of the Centro de Diagnóstico de Enfermedades Moleculares (CEDEM); and Dr. Encarna Guillén Navarro, president of the Asociación Española de Genética Humana (AEGH), researcher at the Instituto Murciano de Investigación Biosanitaria Pascual Parrilla and CIBERER, currently head of the Genetics Department at Hospital San Juan de Dios in Barcelona, and strategic director of the ÚNICAS-SJD project. Hosting this event at the IIBM provided a unique opportunity to exchange scientific information, share personal experiences from patients and their families, and highlight the urgent need for increased investment in rare disease research.
During the opening session, IIBM director Pilar López Larrubia introduced the CSIC Rare Diseases Network (RER-CSIC), created in 2024, which she coordinates alongside Pascual Sanz from the Instituto de Biomedicina de Valencia. So far, RER-CSIC encompasses 127 CSIC research groups distributed across six work areas. Pilar explained that the network's objectives are focused on promoting collaborative research in these pathologies.
Belén Pérez discussed the difficulties in diagnosing diseases related to metabolic disorders and how the application of recently implemented omics technologies has made it possible to diagnose extremely complex cases due to the nature of mutations in the implicated genes. Currently, 1,988 rare metabolic diseases have been cataloged, of which only 275 have treatments, and more than 30% remain undiagnosed. Fortunately, initiatives are now in place to collectively study all undiagnosed rare diseases.
Two members of the Asociación Española de Paraparesia Espástica Familiar spoke about diseases that cause paraparesis—serious conditions that still lack an adequate therapeutic plan. María José Rangel Viejo detailed the many limitations faced by these patients and the extensive care they require, including physiotherapy, orthopedics, and more. There are 129 genes associated with paraparesis, and one of the conditions, SINO Syndrome, was discussed by Teresa Iglesias. This pediatric disease affects motor neurons that innervate the lower limbs, among other symptoms. Mutations in the KIDINS220 gene, studied in her laboratory, cause this syndrome.
Soledad Bárez presented her research on Allan-Herndon-Dudley Syndrome, a disorder caused by deficiencies in the thyroid hormone transporter in brain barriers and the plasma membrane of neural cells, known as MCT8. In animal models, her team is testing various drugs to repair MCT8 deficiency and is also exploring gene therapy experiments to introduce the transporter. Following this, Eva María Fernández Alcolado, the mother of a patient affected by this disease, shared the many challenges faced by families, including the lack of support, bureaucratic obstacles, difficulties balancing work and caregiving, and the shortage of speech therapists in hospitals. Eva María remarked that “rare diseases still do not exist” in terms of public awareness and support.
Next, we learned about Kawasaki Disease. Elisa Fernández Cooke, a pediatrician at Hospital Universitario 12 de Octubre, emphasized the importance of early diagnosis in children with clinical suspicion to prevent giant aneurysms, the most serious complication associated with this rare disease. Elisa is committed to teaching primary care pediatricians how to distinguish this condition from other infections. Silvia Martín Puig then explained the new multi-omics analysis strategies used in her laboratory to explore the molecular basis of Kawasaki Disease, identify diagnostic biomarkers, and detect possible genetic variants associated with the condition through translational research. María José García Fernández described the objectives of the Asociación de la Enfermedad de Kawasaki (Asenkawa), which include supporting families through accompaniment programs and raising awareness about the disease and its potential long-term effects to better manage the uncertainty that comes with a Kawasaki Disease diagnosis.
Frontotemporal dementia (FTD) primarily affects the frontal and temporal lobes of the brain, leading to hippocampal atrophy. It is the most common form of dementia in people under 65. Isabel Lastres is leading crucial research on the molecular basis of this disease to open new avenues for developing treatments that could alter its progression—something currently unavailable for FTD. Miguel Ángel Maroto Serrano, from the Madrid delegation of the Asociación de Demencia Frontotemporal (AhoraCentros), described the challenges faced by caregivers and the lack of specialized social and healthcare resources. He also explained the signs and symptoms of this devastating dementia, which often manifests in people still of working age. Early diagnosis is essential, and cognitive stimulation in mild stages can help slow the decline. These collective efforts are crucial to advancing the understanding and treatment of FTD, a disease that, while less well-known than Alzheimer’s, significantly impacts the quality of life of both patients and their families.
The closing session was led by Encarna Guillén Navarro, who spoke about the ÚNICAS project, an initiative by Hospital San Juan de Dios. This platform aims to integrate hospitals that treat pediatric rare diseases, with goals including comprehensive care for children in the hospital system, accelerating diagnoses, applying advanced therapies, and even enabling patient monitoring from home through telemedicine. A Precision Medicine Center will soon open next to Hospital San Juan de Dios to serve rare disease patients and their families in a supportive environment.
The organizers of this event were Soledad Bárez, Paula Clemente, Ricardo Escalante, Miguel Fernández-Moreno, Silvia Murillo, Víctor L. Ruiz Pérez, and Belén Peral