Rare diseases in Croatia--lesson learned from Anderson-Fabry disease.

es, have a very low incidence and include diseases that occur at a prevalence of less than 5 cases per 10 000 people in the overall population (1). New rare diseases are discovered every year, and some of today’s known diseases in this category have patient populations of fewer than a hundred (2). In a country like Croatia (population of 4.5 million), most physicians do not see a single patient with a rare disease during their entire career. Hematologists, pathologists, and other specialists in main hospital centers would probably see not more than one case in several years. Rare diseases are mostly genetic. Many of them are life-threatening or chronically debilitating. The prevalence of rare diseases may vary between different populations. In some populations they may be slightly more frequent than in others, which is especially true for genetic, infectious, or malignant diseases. For example, cystic fibrosis is very rare in Asia but relatively common in Europe. Other diseases, such as many rare forms of cancer, have no apparent pattern of distribution but are simply rare in most countries. European Organization for Rare Diseases (EURODIS) estimates that there are between 5000 and 8000 distinct rare diseases affecting 68% of the population (3). From a societal point of view, many patients and families affected by a rare disease are often isolated and thus vulnerable to stress. The life expectancy of patients with rare diseases is significantly reduced. Many of them have disabilities that may become a cause for discrimination, which in turn might reduce educational, professional, or social opportunities for these persons. The research on rare diseases is scarce. The lack of specific health policies and the scarcity of expertise translate into delayed appropriate diagnosis and difficulty of access to care.