Narod SA. Tamoxifen ChemopreventionâEnd of the Road?. JAMA Oncol. 2015;1(8):1033â1034. doi:10.1001/jamaoncol.2015.2247. Download citation file:
About Rare Diseases. A rare disease is defined by the European Union as one that affects less than 5 in 10,000 of the general population. There are between 6,000 and 8,000 known rare diseases. Around five new rare diseases are described in medical literature each week.
Rare Diseases. Canavan disease is one of a group of genetic disorders called leukodystrophies that result in defects in the myelin sheath that covers nerve cells in the brain. In Canavan disease, a âgenetic mutation on chromosome 17 causes a deficiency of an enzyme called aspartoacylase.