Typically, genetic disorders are caused by abnormalities in a person's genome. This abnormality can be trivial or major. They generally range from discrete mutations to gross chromosomal abnormalities. Certain genetic disorders are inherited from parents, and other disorders are the result of mutations in a group of genes, or a single gene. The types of human genetic disorders can be divided into three categories: single gene inheritance, multifactorial inheritance, and mitochondrial inheritance.
Typically, mutations occur randomly or may be related to certain types of environmental exposure. Generally, genetic disorders that are caused by mutations in single genes include cystic fibrosis, Marfan syndrome, and sickle cell anemia. These genetic disorders occur in approximately one of 200 births, and are referred to as monogenetic disorders. Cystic fibrosis is a genetic disorder that is familiar to many. It is characterized by copious amounts of thick mucous that is difficult to expectorate, which causes intractable coughing.
Multifactorial inheritance conditions are caused by mutations in more than one gene. In addition, they may also be caused by environmental factors as well. Examples of these genetic disorders include heart disease, Alzheimer's disease, and heart disease. In addition, chronic diseases such diabetes, cancer and arthritis are examples of this type of disorder. Multifactorial inheritance disorders are also associated with inherited traits such as height, skin color, and eye color.
Generally, chromosomal abnormalities cause genetic disorders such as Turner syndrome, cri du chat syndrome, which translates into "cry of the cat," and Klinefelter syndrome. These types of genetic disorders generally occur as a result of cell division problems. Down syndrome, for example, is a disorder that happens as a result of having three copies of the chromosome 21. Another term that refers to Down Syndrome is trisomy 21. Typically, Down Syndrome is diagnosed at birth, however, it can take months before it becomes apparent.
Other types of genetic conditions include mitochondrial inheritance disorders. These conditions are caused by a mutation in nonchromosomal mitochondria DNA. Mitochondria refers to small organelles involved in the process of cellular respiration and is found in plant cytoplasm and animal cells. Included in the list of mitochondrial diseases are myoclonus epilepsy, Leber's optic atrophy, which is an eye disease, and mitochondrial encephalopathy, which is a type of dementia.
It is important to note that many of these conditions are uncommon, however, great strides in research are being conducted into the cause and treatment of such conditions. Typically, many large university teaching hospitals have departments specifically dedicated to genetics and related disorders. Genetic testing is available to individuals who may be seeking information about their genetic disposition. In addition, these tests may be beneficial to rule out certain genetic conditions.