Question

What is the genotype and phenotype of a carrier of sickle-cell anaemia?

Options

• HbA HbS; Severe anaemia, sickle-shaped RBCs

• HbS HbS; Severe anaemia, sickle-shaped RBCs

• HbA HbA; Normal RBCs

• HbA HbS; Mostly normal, mild anaemia under stress

Answer 1

An individual with genotype HbA HbS is a carrier of sickle-cell trait. The phenotype shows mostly normal red blood cells with only mild anaemia under stress conditions. This heterozygous state provides some protection against malaria while avoiding the severe symptoms of the homozygous sickle-cell disease.