Saturday, 17 November 2007

Genetic disorders

Genetic disorders
1. Single gene disorders
2. Mitochondrial disorders
3. Chromosomal disorders
4. Multifactorial disorders

1 comment:

praspowt said...

Geneticists group genetic disorders into three categories:
Single gene disorders are caused by a mutation in a single gene. The mutation may be present on one or both chromosomes (one chromosome inherited from each parent). Sickle cell disease, cystic fibrosis and Tay-Sachs disease are examples of single gene disorders.

Chromosome disorders are caused by an excess or deficiency of the genes that are located on chromosomes, or structural changes within chromosomes. Down syndrome, for example, is caused by an extra copy of chromosome 21, but no individual gene on the chromosome is abnormal.

Multifactorial inheritance disorders are caused by a combination of small variations in genes, often in concert with environmental factors. Heart disease and most cancers are examples of these disorders. Behaviors are multifactorial, complex traits involving multiple genes that are affected by a variety of other factors. Researchers are learning more about the genetic contribution to behavioral disorders such as alcoholism, obesity, mental illness and Alzheimer disease. There is currently no recommended genetic testing for behavioral disorders such as alcoholism or obesity.