Question

Name two genetic diseases in humans.

Answer 1

• Haemophilia and Down syndrome
• Above mentioned both the disease are genetic disorders.
• Haemophilia is a sex-linked recessive disorder. This disease is mostly seen in males and females are usually the carrier of the disease. The recessive allele for the disease is present on the X chromosome. This disease is usually passed on from the carrier female to its male progeny who is affected by the disease as males have only one X chromosome in their genotype, while the female progeny of the carrier female can either be a carrier or not it depends on which X chromosome from the mother is passed down to the female as one X chromosome comes from the father. For a female to be affected by this disease both the parent have to be the carrier or the mother has to be affected by the disease ie should be homologous for the disease genotype. In this disease, a protein in the cascade of blotting clotting process is not formed or is defected due to which even in a simple cut the blood will not clot and will continue to bleed.
• Down Syndrome is a chromosomal disorder which is caused by the trisomy condition of the chromosome number 21 one where there is 3 chromosome present in the place of a pair of 2 chromosomes. The individual who is affected with the disease has a retarded growth with small stature, round head, round and bulging eyes, furrowed and thick tongue; metal growth is also retarded in these patients.