Question

which genetic disease never has healthy carriers?

• sickle-cell anemia
• huntington disease
• cystic fibrosis
• tay-sachs disease

Explanation:

• Sickle - cell anemia: It is an autosomal recessive disorder. People with one copy of the mutant gene (carriers) have sickle - cell trait and are generally healthy.
• Huntington disease: It is an autosomal dominant disorder. If a person has the mutant allele, they will develop the disease. There are no healthy carriers as having the allele means having the disease.
• Cystic fibrosis: It is an autosomal recessive disorder. Carriers (heterozygotes) are healthy.
• Tay - Sachs disease: It is an autosomal recessive disorder. Carriers (heterozygotes) are healthy.

Answer:

B. Huntington disease