Question

True statement regarding Huntington’s chorea is

• A. There is a loss of function type of mutation
• B. It is an autosomal recessive
• C. It is a trinucleotide repeat expansion type of disorder
• D. Increased number of CAA repeats

Answer 1

The Correct Option is C

Huntington's chorea, also known as Huntington's disease, is a neurodegenerative genetic disorder characterized by the following key points:

1. Trinucleotide Repeat Expansion: Huntington's disease is indeed a trinucleotide repeat expansion disorder. It involves the expansion of the CAG (cytosine-adenine-guanine) repeat in the HTT gene.
2. Autosomal Dominant Inheritance: The disease is not an autosomal recessive condition. It follows an autosomal dominant pattern of inheritance, meaning only one copy of the mutated gene from either parent is sufficient to cause the disorder.
3. Gain of Function Mutation: This disorder results from a gain of function mutation due to the expanded CAG repeats, leading to the production of an abnormally long polyglutamine tract within the huntingtin protein, which is toxic to neurons.
4. Incorrect Repeat Type: The statement about increased number of CAA repeats is incorrect in the context of Huntington’s disease. It specifically involves CAG repeats.

Given these explanations, the true statement regarding Huntington’s chorea is: It is a trinucleotide repeat expansion type of disorder.