Question

Which of the following statements is correct with respect to sickle cell anaemia?

• A. Homozygous individuals for HbA show the diseased character.
• B. Heterozygous individuals are affected as well as carriers.
• C. Homozygous individuals for HbS remain unaffected.
• D. Heterozygous individuals for HbS and HbA exhibit sickle cell trait.

Answer 1

Answer: (D)

Sickle cell anaemia is an autosomal recessive disease. This disease is controlled by a pair of alleles: HbA (normal dominant allele) and HbS (affected recessive allele).
Both male and female have either of the three genotypes:
1. HbA HbA: Normal phenotype.
2. HbA HbS: Normal phenotype.
3. HbS HbS: Diseased phenotype.