Question

Which of the following is not an X-linked recessive disease?
A. Beta-thalassemia
B. Haemophilia
C. Colour blindness
D. Glucose-6-phosphate dehydrogenase deficiency

Answer 1

Disease is the illness of the body. Disease is the abnormal condition which negatively affects the structure and function of the body.

Complete Answer:
A. Beta-thalassemia: Beta-thalassemia is an inherited blood disorder. In this disease the production of Haemoglobin gets reduced.
- Haemoglobin is an iron containing protein in red blood cells which is responsible for the transport of Oxygen to all the cells of the body.
- Low level of haemoglobin leads to lack of oxygen in many parts of the body in affected persons.
- Affected people also have anaemia which is caused by the shortage of red blood cells and which cause pale skin, weakness, fatigue, etc.

B. Haemophilia: Haemophilia is also called as the bleeder's disease in which a person bleeds a lot even on a small injury.
- Haemophilia is a X-linked recessive genetic disorder in which people loses the ability of forming blood clots which result in both external and internal bleeding.
- There are two types of haemophilia.
Haemophilia A – It is caused by the low amount of blood clotting factor VIII.
Haemophilia B – It is caused by the low level of clotting factor IX.

C. Colour blindness: Colour blindness is an X – linked recessive disorder.
- This disease can be inherited from the parents to the offspring.
- Colour blindness is a disease in which an affected person loses its ability to differentiate into different colours or see colours.
- The colour blindness is caused by the problem in the development of the one or more sets of the cone cells of the eyes which are responsible for colour vision.

D. Glucose-6-phosphate dehydrogenase deficiency: Glucose-6-phosphate dehydrogenase deficiency disease (G6PDD) is an X-linked recessive disorder which results in the defective glucose-6-phosphate dehydrogenase enzyme.
- It is an inborn error of metabolism that predisposes to red blood cell breakdown.
- The affected person shows symptoms like yellowish fever, dark urine, shortness of breath, etc.

Note: X-linked recessive disorders mostly occur in the males because males have only one X chromosome. A single recessive gene on the X chromosome causes a disease in males. Male contain a second chromosome as Y. Since Y does not contain most of the genes of X chromosome, hence it can’t protect the males from the disease.