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GENETIC DISORDERS



        Any variation in number of chromosomes (increase or decrease in the number of chromosomes) from normal number, or a change in the shape of a chromosome during the fertilization which leads to severe abnormality or disorder in the child after birth is called genetic disorders. The treatment of genetic diseases is not still possible, but the scientists are doing their best to find out their treatments. The important examples of genetic disorder are:

    1. Down’s syndrome
    2. Turner’s syndrome
    3. Klinefelter’s syndrome
    4. Supermales
    5. Superfemales

1. Down’s SyndromeKaryotype of a person suffering from Down’s syndrome

        Down’s syndrome is a genetic disorder. It is caused by the presence of an extra chromosome in 21st pair. This means that a person suffering from Down’s syndrome possesses 3 chromosomes in its 21st pair of chromosome, which can be seen clearly in the figure of the karyotype of the person suffering from Down’s syndrome.

Symptoms

Person suffering from Down’s syndrome        A person suffering from Down’s syndrome shows mental retardation, rounded face, broad forehead, flattened nose, widely separated eyes, permanently open mouth, protruding tongue, short neck, flat hands and stubby fingers.

2. Turner’s Syndrome

Women suffering from Turner’s Syndrome        This genetic disease is found in women. The women suffering from Turner’s syndrome have only 45 chromosomes as compared to the normal number of chromosomes of 46.

Symptoms

       The women suffering from Turner’s syndrome are sterile with reduced ovaries, underdeveloped breasts, loose skin of the neck and abnormal intelligence. Such women may not menstruate or ovulate.

3. Klinefelter’s Syndrome

Person suffering from Klinefelter’s Syndrome        This disorder is found in males. In this disease the concerned person possesses one more chromosome. Thus he possesses 47 chromosomes as compared to the normal number of chromosomes of 46.

Symptoms

       The person who suffers from klinefelter’s syndrome is a sterile male with small testes, long legs, mental retardation, and obesity. Such persons also have characteristics of females such as breasts and less hair on the body.

4. Supermales

       This disorder is also found in males. In this disorder the male possesses one additional Y chromosome. Their genotype can be represented as 44 autosomes + XYY.

Symptoms

       Such males usually suffer form unusual height, mental retardation and more aggressiveness than normal males.

5. Superfemales

       This disorder is found in females. In this disorder the females possess one additional X chromosome. Their genotype can be represented as 44 autosomes + XXX.

Symptoms

       Such females usually suffer from mental retardation and abnormal sexual development.




Test Your Understanding and Answer These Questions:




  1. What are genetic disorders? Name some genetic disorders.

  2. What is Down’s syndrome? What are symptoms of Down’s Syndrome?

  3. What is Turner’s syndrome? What are symptoms of Turner’s Syndrome?

  4. What is Klinefelter’s syndrome? What are symptoms of Klinefelter’s Syndrome?

  5. What are supermales? What are symptoms of supermales?

  6. What are superfemales? What are symptoms of superfemales?