Question

Which of the following is not true to haemophilia?
A) Royal disease
B) Bleeder’s disease
C) X-linked disease
D) Y-linked disease

Answer 1

Sex-linked diseases are passed down by one of the X or Y chromosomes of families. X and Y are sex chromosomes. Dominant inheritance occurs when an abnormal gene from one parent causes disease, even though the matching gene from the other parent is normal.

Complete answer:
Haemophilia is an inherited genetic disorder that disables the body's ability to clot blood, a process needed to stop bleeding. There are several clotting factors in our blood which are responsible for clotting of blood. In haemophilia, such factors are not present in enough quantity to ensure the clot formation. The person suffering from it continues to bleed even after an easy bruising, and an increased risk of internal bleeding. Individuals with a mild case of the disease may have symptoms only after getting into an accident or during surgery. It is a sex linked recessive disorder. It is X-linked. Females are carriers of the disease due to the presence of another X chromosome, it is only expressed in males who have a single X chromosome. A carrier female has a 50% chance of passing the faulty X-chromosome to her daughter, but an affected male will always pass on the affected gene to his daughters. A son cannot inherit the defective gene from the male parent. Haemophilia is of three types, haemophilia A, haemophilia B and haemophilia C. type A and B are sex linked while type C is autosomal linked disorder.
Haemophilia B flows through the royal family of Europe. Queen Victoria was a carrier and passed the disorder to her progeny.

Therefore, the correct answer is- D. Y-linked disease.

Note: Haemophilia is a sex linked recessive disorder, linked to the X chromosome. The blood does not clot if a person gets a cut due to this disease.