Question
Question: Phenotypically females having rudimentary ovaries, underdeveloped breasts, short stature, webbed nec...
Phenotypically females having rudimentary ovaries, underdeveloped breasts, short stature, webbed neck, often subnormal intelligence suggests
A.Down’s syndrome
B.Klinefelter’s syndrome
C.Turner’s syndrome
D.Haemophilic syndrome
Solution
We know that certain diseases are inherited to the children from their parents. These diseases are called genetic diseases. Genetic diseases are classified into two groups. They are mendelian disorders and chromosomal disorders.
Complete answer: We know that certain diseases are caused because of mutations that happens in a single gene. These disorders are called Mendelian disorders. Chromosomal disorders are caused by changes in the number and arrangements of the chromosomes.
Turner’s syndrome is a chromosomal disorder caused due to the absence of one of the X chromosomes in females. Chromosomes of these patients are represented as ’45 with X0’.
Here, the patients are phenotypically female. But as they lack one of the X chromosomes, they have underdeveloped secondary sex characters. These are short statured females with rudimentary ovaries. Because of this reason, these individual are not able to reproduce and are considered sterile. Underdeveloped breasts, webbed neck and mental retardation are also common in Turner’s syndrome.
Down’s syndrome is caused by an extra copy of chromosome in chromosome 21. It is called trisomy of 21 as one chromosome is added. This disease is commonly called Mongolian idiocy.
In Klinefelter’s syndrome, extra X chromosome is seen in males. Here, the person is phenotypically male with some feminine characters.
Hence the correct option is C.
Note: Haemophilia is actually a disorder in which excessive bleeding is seen in patients even from small injuries. It is sex linked recessive disease and consists of two types. They are haemophilia A and B. As the disease is sex linked and recessive in nature, males are more susceptible to this disease than females. It is because both the X chromosomes should be diseased for the females to be haemophilic, but for males, only one is necessary.