List of genetic disorders

From ArticleWorld

Genetic disorders are afflictions of genetic nature, caused by an abnormal expression of genes. There are various reasons for the appearance of these genetic disorders, including gene mutations, abnormal chromosome numbers, defective genes etc. At the moment, about 4,000 genetic disorders are known, but the list is expanding.

Common genetic disorders

There are many genetic disorders that can occur in humans, but most of them only seldom appear. The most common ones include:

• Angelman Syndrome is usually caused by the loss of normal maternal contribution to a part of chromosome 15. It is associated with severe learning difficulties and a typical facial appearance.

• Canavan disease appears because of a defective ASPA gene, causing progressive damage to the nerve cells located in the brain.

• The Charcot-Marie-Tooth disease is an inherited, incurable neuropathy which causes the loss of muscle tissue in feet and legs, but also in hands and arms in advanced stages.

• Color blindness is a common color deficiency which causes the inability to distinguish between some or all colors. It can also have non-genetic causes.

• Cystic fibrosis is an autosomal recessive hereditary affection of the exocrine glands, affecting the lungs sweat glands and the digestive system.

• Down's Syndrome is usually caused by a trisomy of chromosome 21, associated with learning difficulties and physical disabilities.

• Haemophilia is an affection that impairs the body's ability to control bleeding.

• Joubert Syndrome is a somewhat less common genetic disorder that affects the brain's ability to maintain balance and coordination.

• Kleinfelter's Syndrome is a disorder caused by a chromosome X non-disjunction in males, causing infertility and sometimes language impairment.

• Neurofibromatosis is an autosomal dominant genetic disorder that causes various physical affections.

• Pelizaeus-Merzbacher disease is a central nervous system genetic disorder which causes delays in coordination, motor abilities and intellectual functions.

• Phenylketonuria is a genetic disorder characterized by the lack of phenylalanine hydroxylase in the human body, causing progressive mental retardation and brain damage.

• Prader-Will Syndrome is a genetic affection in which some genes of the chromosome 15 are missing or unexpressed, mental retardation, hypotonia and morbid obesity later.

• Spina bifidia is a genetic disorder characterized by incomplete closure of some vertebral arches of the spine, causing malformations of the spinal cord.

• Tay-Sachs disease is a deadly genetic disease occurring because large quantities of ganglioside GM2 accumulate in the nerve cells in the brain.

• Turner Syndrome is a genetic disorder cause by a non-disjunction in a female's sex chromosome.

The genetic disorders themselves are not treatable, but various medical actions can be taken to lighten the symptoms.