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Genetic disorders that can be revealed by kariotype analysis.

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Genetic disorders that can be revealed by kariotype analysis Among the numerous genetic disorders that contemporary medicine knows about are some that are caused by changes in number and structure of chromosomes. Therefore, they can be investigated by kariotype analysis. I would like to describe some of the most well-known disorders caused by numerical aberrations in chromosomes. First of all, numerical changes can be either: * Polyploidy - condition in which there are more than two complete sets of corresponding chromosomes. Triploidy and tetraploidy are the most common forms of polyploidy. It is naturally occurring in plants. In humans, polyploidy is lethal. * Aneuploidy - condition in which in one pair of chromosomes there is one more (trisomy) ...read more.


is usually lethal in early foetal development. There are few genetic diseases that are results of aneuploidy: 1. Down's Syndrome - it is the most common of trisomies (1/650 newborns) and perhaps also the most well-known. It is caused by trisomy in the 21st pair of chromosomes?. Among the symptoms is always mental retardation to different extent. Other phenotypic features are various - they occur to different extent, be present, or not at all. Some of the most common phenotypic features include: big distance between I and II toes, open mouth, short neck, short and broad palms, big tongue, heart defects. 2. Edwards' Syndrome - occurs in 1/3500 newborns and is caused by trisomy in the 18th pair of chromosomes. ...read more.


The frequency of appearance is 1/2500 newborn girls. In Poland, there are about 9000 women with the disease and 100 are born with it annually. The characteristic features of girls suffering from the disorder are: too much skin on the neck, lymphatic oedema of limbs, being short height, reproductive organs not fully developed, numerous defects of internal organs. A girl treated with growth hormone, taking it everyday for several years, can eventually reach the height of a small normal woman as an adult. It is worth noting that the risk of giving birth to a child showing aneuploidy rises with the age of the mother. Therefore, if the mother is over 35, or genetic disorders occurred in close family of either the father or the mother, the prospective parents are advised to seek help from genetic counselling. ...read more.

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