Who is Genetic Disorders ?

A genetic disorder is a condition caused by abnormalities in genes or chromosomes. While some diseases, such as cancer, are due to genetic abnormalities acquired in a few cells during life, the term "genetic disease" most commonly refers to diseases present in all cells of the body and present since conception. Some genetic disorders are caused by chromosomal abnormalities due to errors in meiosis, the process such as the reproductive cells which produce sperm and eggs. Examples include Down syndrome (extra chromosome 21), Turner Syndrome (45X0) and Klinefelter syndrome (a male with 2 X chromosomes). Other genetic changes may occur during the production of germ cells from the father. One example is the mutation of repeat expansion of the trio that can cause fragile X syndrome or Huntington's disease. The defective gene can also be inherited intact from the parents. This can often happen unexpectedly when two healthy carriers of a defective recessive gene reproduce, but can also happen when the defective gene is dominant. About 4,000 genetic disorders are currently known, with more being discovered. Most disorders are quite rare and affect one person in every several thousands or millions. Cystic fibrosis is one of the most common genetic disorders, around 5% of the population of the United States carry at least one copy of the defective gene. Some types of recessive gene disorder confer an advantage in heterozygous state in certain environments.