Question

Which of the following is a recessive genetic disorder?

• A. Huntington's disease
• B. Sickle cell anemia
• C. Achondroplasia
• D. Marfan syndrome

Hint:

If a question lists common genetic diseases, remember that Sickle Cell, Cystic Fibrosis, and Phenylketonuria (PKU) are classic examples of autosomal recessive inheritance.

Answer 1

The Correct Option is B

The question asks to identify a recessive genetic disorder from the given options. Let's analyze each option to determine the correct one:

1. Huntington's disease: This is a dominant genetic disorder caused by a mutation in the HTT gene. Since it is dominant, individuals with just one copy of the mutated gene will exhibit symptoms. Therefore, it is not a recessive disorder.
2. Sickle cell anemia: This is a recessive genetic disorder caused by a mutation in the HBB gene on chromosome 11. An individual needs to inherit two copies of the mutated gene (one from each parent) to exhibit the disease. Therefore, sickle cell anemia is indeed a recessive genetic disorder.
3. Achondroplasia: This is a dominant genetic disorder affecting bone growth, leading to dwarfism. Since it is caused by a dominant gene mutation, it is not a recessive disorder.
4. Marfan syndrome: This is a connective tissue disorder caused by a mutation in the FBN1 gene. It follows an autosomal dominant inheritance pattern and thus is not a recessive disorder.

Based on the evaluation of the options, Sickle cell anemia is the correct answer as it is a recessive genetic disorder.