Quote:
Originally Posted by Mehrankhan
Thanx friend... aik request aur hay.. kindly tell me about chromosomal abnormalities.. do they come in paper??? Give any link on this topic too..
Thanku..
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Yes,it is Important.
Human Chromosomal Abnormalities
1. Down Syndrome(Extra X chromosome)
2.Klinefelter Syndrome(XXY in Male)
3. Fragile X syndrome
4. Meta Females(XXX)
5. XYY Syndrome
6. Turner Syndrome XO
1.Down syndrome
It is caused by an extra chromosome 21. People with Down syndrome are usually mentally retarded and have a host of physical defects, including heart disorders. Other individuals, called Down syndrome mosaics, have a mixture of normal cells and cells with three copies of chromosome 21, resulting in a mild form of the disorder.
2.Klinefelter's syndrome
In this Syndrome a male has two X chromosomes (XXY). This condition occurs in 1 out of every 2,000 births (1:800 males about). Men with Klinefelter's syndrome have small testes and are usually sterile. They also have female sex characteristics, such as enlarged breasts (gynecomastia). Males who are XXY are of normal intelligence or affected by a mild delay or behavioural immaturity. However, males with more than two X chromosomes, such as XXXY, XXXXY, or XXXXXY are mentally retarded.
3.Fragile/Weak X chromosome:
An Abnormality in X chromosome.it causes learning disabilities,mental retardation,delayed speech etc.
4.Meta Females
Females with an extra X chromosome (XXX) are called metafemales. This defect occurs in 1 out of every 800 females Metafemales have lowered fertility (oligomenorrhea and premature menopause), but their physical appearance is normal
5.XYY Syndrome
Males with an extra Y chromosome (XYY) have no physical defects, although they may be taller than average. XYY males occur in 1 out of every 2,000 births (1:800 males about). It is not associated with increased aggressive and criminal behaviour as initially thought.
6.Turner Syndrome
Females with only one X chromosome (XO) have Turner syndrome. Turner syndrome is also called monosomy X and occurs in 1 out of every 5,000 births (1:2,500 females). People with Turner syndrome have sex organs that do not mature at puberty and are usually sterile. They are of short stature and have no mental deficiencies.