Misha was born on July 3, 2025. Six days later, on the 9th, his mother, Madona, received a call from Vall d'Hebron University Hospital in Barcelona requesting her admission. The heel prick test performed on her son at the hospital where he was born showed results that were confirmed shortly afterward: severe combined immunodeficiency (SCID). This disease is caused by a disorder of several genes that prevent the development of the immune system, responsible for fighting all kinds of infections. The first response is to isolate the patient. So Madona and her son went to live in a hospital room while they waited for Misha to receive the treatment that would cure him. He had to reach three months of age or weigh five kilos. "I was with him in the hospital the whole time until they were able to perform a transplant. It was very hard, although Dr. Andrea Martín's medical team made everything very easy for us," Madona recalls. Severe combined immunodeficiency (SCID) is one of the many and diverse rare diseases that exist, and this Saturday, February 28th, is the day commemorated. "A disease is considered rare when it affects fewer than one in 2,000 individuals. It's a small part of the population, but precisely for that reason, extra effort must be dedicated to dissemination, so that affected families can have the option of consulting the appropriate referral centers and so that the country's healthcare centers are prepared to care for these patients, with complex conditions that affect..." says a pediatrician and member of the Pediatric Infectious Diseases and Immunodeficiencies Unit (UPIIP) at the Vall d'Hebron University Hospital.