Genetic Diseases Are Typically Diagnosed And Treated By Geneticists

Genetic disorders take place as a result of various abnormalities or variations in the information encoded by the genes and chromosomes. As per the available information based on researches on genetic disorders, these genetic disorders can be broadly classified into four different categories, which are as follows.

Single-gene Disorders is the first type of genetic disorder which is also known as Mendellian or monogenic disorders, these occur when the changes or mutations occur in only a single gene. Some well-known instances of single-gene disorders include Marfan syndrome, cystic fibrosis, sickle cell anemia, Huntington's disease and hereditary hemochromatosis. Single gene disorders can further be classified into autosomal recessive, autosomal dominant, X-linked dominant, X-linked recessive and Y-linked disorders. Multifactorial Genetic Disorders is the second type of genetic disorder and it is also known as polygenic, these disorders occur as a result of mutations in multiple genes. These genetic disorders are really complex, difficult to analyze and hard to treat. Some well known examples of multifactorial disorders include cleft palate, autism, coronary heart diseases, mental retardation, cancer and diabetes.

Chromosomal Disorders are the third type of genetic disorder. These types of genetic disorders occur as a result of abnormalities in the chromosomal structure such as missing or presence of extra copies of chromosomes. The most recognized chromosomal disorder is the Down syndrome or Trisomy 21 where a person has three copies of chromosome 21. Other well known examples of this disorder include Klinefelter syndrome, Cri-du-Chat syndrome, Turner Syndrome and Williams' syndrome. Mitochondrial Disorders is the forth type of genetic disorder which occur when there are mutations in the mitochondrial DNA or the non-chromosomal DNA of the cell. These types of disorders are maternal in origin as only egg cells contribute mitochondria in a developing embryo. One very good illustration of a mitochondrial disorder is the Leber's Hereditary Optic neuropathy.

DNA testing or genetic testing is a relatively modern development due to advances in scientific knowledge, and besides the purpose to know the cause of genetic disorders the testing has many and varied uses including paternity testing, testing for various genetic diseases during pregnancy, or for forensic investigations. In fact the first purpose of genetic testing is called paternity testing and is used to verify who the biological father of a child is. When there is a distrust or confusion about who is the biological father of a child, this testing process can hold not only implications for the relationship both between the parents and between the father and child; but also legal and financial implications. Genetic testing in this case can be done through collecting a sample of the mother's, father's and child's DNA which are then compared at various points. This testing method of verifying paternity is a lot more accurate than older methods and is also painless as a DNA sample can be collected from a swab of the cheek.

Another use of genetic testing is to help create the family tree and verify family history. In this process parts of the Y chromosome that don't tend to change down through the generations will be compared to others. People who have a common ancestor will normally show similar characteristics in certain places of this specific chromosome and so will help establish ancestral lines.

• Felicia Byrnes
• 12/01/2009, 6:59 PM
• 0 Comments