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.
Medical Definition of Severe combined immunodeficiency disease. Severe combined immunodeficiency disease: A combined deficiency of the immune system in which its two major weapons, antibodies and T cells, are genetically missing or disabled. Severe combined immunodeficiency disease (SCID) is rare. The chances of a child being born with SCID are about one in 500,000 births.