In the last leap year in 2008, 29 February was chosen to mark Rare Disease Day by EURORDIS, the European Organisation for Rare Diseases. This year, this rare day will again serve to raise awareness of the plight of patients with rare disorders.

Rare diseases fail to attract commercial research efforts because of the small number of people affected (fewer than 5 in 10,000). Examples include the nerve disorder Charcot–Marie–Tooth disease and Proteus syndrome, which causes excess overgrowth of tissues.

As a result, only a handful of scientists, often working in isolation, dedicate their research to a particular rare disease. But such select studies can deliver groundbreaking insights into more general disease processes. Exposure of molecular mechanisms underlying rare diseases therefore has the potential to help many other patients.

Also on 29 February, the first international congress dedicated to rare diseases will be held in Basel, Switzerland (www.react-congress.org). It will highlight the recently established International Rare Diseases Research Consortium (IRDiRC), which plans to coordinate international policy-making with results from national research projects. These initiatives should eventually translate scientific advances into benefits for patients.