Opitz C syndrome is a genetic disease that causes severe disabilities in patients and has been diagnosed in three people in the Iberian Peninsula, and sixty people in the world. A team of researchers has now identified a gene that causes the Opitz C syndrome in the only patient in Catalonia diagnosed with this severe congenital disease. This new scientific advance is a first step to discover the genetic bases of this syndrome which, so far, does not offer treatment possibilities, prenatal diagnosis or genetic counseling.