Question

Which of the following occurs due to the presence of an autosome linked dominant trait?

• A. Sickle cell anaemia
• B. Myotonic dystrophy
• C. Haemophilia
• D. Thalassemia

Answer 1

The Correct Option is B

An autosomal dominant trait is a trait that is expressed when at least one dominant allele is present on one of the non-sex chromosomes (autosomes). In terms of genetic disorders, the presence of one copy of the mutant allele is sufficient to cause the disorder. Let’s analyze the options:

1. Sickle cell anaemia: This is an autosomal recessive disorder, not autosomal dominant, caused by a recessive allele.
2. Myotonic dystrophy: This is indeed an autosomal dominant disorder characterized by progressive muscle wasting and weakness. The trait is expressed even if only one copy of the mutated gene is present.
3. Haemophilia: This is a sex-linked recessive disorder, not autosomal dominant, typically associated with the X chromosome.
4. Thalassemia: This is generally an autosomal recessive disorder affecting the blood.

Based on the characteristics of the disorders and the definition of an autosomal dominant trait, the correct answer is Myotonic dystrophy.