Question: 140: Which of the following occurs due to the presence of autosome linked dominant trait ?
(1) Haemophilia
(2) Thalessemia
(3) Sickle cell anaemia
(4) Myotonic dystrophy
Answer: Option (4)
Explanation:
Autosomal dominant traits are expressed even when only one copy of the mutant allele is present on an autosome.
Myotonic dystrophy is a well-known autosomal dominant disorder characterized by progressive muscle weakness and delayed muscle relaxation.
Haemophilia is an X-linked recessive disorder and therefore not autosomal dominant.
Thalassemia and sickle cell anaemia are autosomal recessive disorders and require two copies of the mutant allele for expression.
Hence, the disorder that occurs due to an autosome linked dominant trait is myotonic dystrophy.