what do you mean by chromosomal disorder?describe the cause and related abnormatities in the following genetic disorder.(a)Down's syndrome
(b)klinefelter's syndrome
(c)turner's syndrome
Answers
Answer:
Klinefelter syndrome is a chromosomal condition in boys and men that can affect physical and intellectual development. Most commonly, affected individuals are taller than average are unable to father biological children (infertile); however the signs and symptoms of Klinefelter syndrome vary among boys and men with this condition. In some cases, the features of the condition are so mild that the condition is not diagnosed until puberty or adulthood, and researchers believe that up to 75 percent of affected men and boys are never diagnosed.
Boys and men with Klinefelter syndrome typically have small testes that produce a reduced amount of testosterone (primary testicular insufficiency). Testosterone is the hormone that directs male sexual development before birth and during puberty. Without treatment, the shortage of testosterone can lead to delayed or incomplete puberty, breast enlargement (gynecomastia), decreased muscle mass, decreased bone density, and a reduced amount of facial and body hair. As a result of the small testes and decreased hormone production, affected males are infertile but may benefit from assisted reproductive technologies. Some affected individuals also have differences in their genitalia, including undescended testes (cryptorchidism), the opening of the urethra on the underside of the penis (hypospadias), or an unusually small penis (micropenis).
Other physical changes associated with Klinefelter syndrome are usually subtle. Older children and adults with the condition tend to be somewhat taller than their peers.
Answer:
Chromosomal disorders is may be due to the changes in number of either autosomes or sex chromosomes or from alteration in the chromosome structure.
Chromosomal disorder is caused by the addition or loss of one (aneuploidy) or more (polyploidy) chromosomes.
(a)Drown's Syndrome :
It is due to the presence of extra chromosome no.21.
It is also referred as a Trisomy 21.
This individuals have 47 (not 46) chromosomes in all their body cells.
Symptoms :
1) abnormalities in facial structure like flattened nasal bridge , protruding lower lips,short and broad neck etc.
2) many 'loops' on finger.
3)Malformation of heart.
(b)Klinefelter's Syndrome
Its due to presence of an extra copy of X chromosomes.hence individual has 47 chromosomes with karyotype of XXY.
The individual is male having undeveloped testis , little hair on body , sterile due to abnormal seminiferous tubules, mentally retarded.
(c) Turner's Syndrome
Its caused by absence of X chromosome.hence individual has only 45 chromosomes with karyotype of XO.
Individual is female but sterile.
Have underdeveloped ovaries.
Have underdeveloped breast.
have subnormal intelligence.