Briefly speaking, rare diseases suggest diseases with low prevalence. Well-known rare diseases include: Spinocerebellar Ataxia, Phenylketonuria, Mucopolysaccharidoses, Osteogenesis Imperfecta (Glass Dolls), Thalessemia and so forth. The number of patients with these rare diseases ranges from hundreds to thousands. Moreover, there have been only several cases of certain rare diseases in the world. Most rare diseases are results of genetic defects, and are often described as congenital diseases. Genetic defects are sometimes caused by sporadic mutation or by inheritance. However, causes of certain rare diseases still remain unknown.
The possibility for this kind of serious health risk at birth is present in all pregnancies. The rate of babies born with the effects of a genetic disease or damage due to complications is around 3-5%. This figure, though seemingly a small consideration, is a real risk that affects millions of births each year. There are about 35,000 genes in human body and each one of us carries around 5 to 10 defective genes. If both parents carry the same defective gene, the risks are much higher that their baby will inherit an active, dominant form of the disease and show the physical effects. The prospective parents could seek out medical counseling to discuss their family histories, their current genetic makeup, and their risks for passing on negative genetic effects. It is also important for the parents to be aware of the lifestyles and environment that they live in which could adversely effect their own health as well as increasing the risks for genetic defects in their children. |
