Question

In the following mendelian disorder substitution of Glutamic acid (Glu) takes place by the valine (Val)?
1. Phenylketonuria
2. Haemophilia
3. Sickle cell anemia
4. Turner's syndrome

Answer 1

Correct Answer - Option 3 : Sickle cell anemia

The correct answer is Sickle cell anaemia.

• Sickle cell anaemia is a mendelian disorder in which substitution of Glutamic acid (Glu) takes place by the valine (Val).

• It is an autosomal linked recessive trait.
• This disease is transmitted from carrier parents to offspring.
• This disease is controlled by two alleles HbA and HbS.
• The homozygous chromosome of this allele is disease-causing whereas heterozygous is not.
• Substitution of codon takes place at the sixth place of the beta-globin chain of haemoglobin molecules.
• Due to which the structure of RBC changed from biconcave disc to elongated sickle cell.