alleryStart learning →Why do hemophilia A and B appear mostly in males?
AThe genes sit on the Y chromosome
BThe genes are autosomal dominant ones
CThe defects are linked to the X chromosome
DMales make fewer clotting factors overall
Answer & Solution
Correct answer: C. The defects are linked to the X chromosome
1. Both hemophilia A and hemophilia B are linked to the X chromosome.
2. Males are XY, so they carry only one X and have no second copy to compensate.
3. A single defective X therefore manifests the disease in a male.
4. Females are XX, so they would need a defective gene from each parent to manifest it.
5. The usual pattern is transmission from a healthy carrier mother to her male offspring.
6. A Y-linked gene could not be passed from mother to son at all, so that option breaks the stated inheritance route.
7. Hemophilia C differs, being autosomal and not a true recessive, which is why it does not show this male predominance.
_Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.5 Hemostasis_
Keep practising The Cardiovascular System: Blood
Browse all The Cardiovascular System: Blood questions for NEET PG, or explore more Physiology topics.
Related questions
When type O blood is not available at a disaster scene, what do medics give to replace losBlood substitutes under development contain which oxygen carriers?In an emergency, which blood types are compatible for a type B recipient?What residual risk remains when type O blood is given to a type A recipient?Which blood type is described as the universal recipient?In an emergency with no time to cross match, which blood type is transfused, and why?A sample agglutinates in the anti-B and anti-D wells but not in the anti-A well. What is tSince RhoGAM was introduced in 1968, hemolytic disease of the newborn in the United States