Which of the following is an example of Trinucleotide repeat mutation –
**Core Concept**
Trinucleotide repeat mutations (TNRs) are a type of genetic mutation characterized by the expansion of a specific sequence of three nucleotides (A, C, G, or T) repeated multiple times in a gene. This type of mutation can lead to various disorders, including neurodegenerative diseases. TNRs are often associated with the instability of the DNA sequence, resulting in the expansion of the repeat sequence over generations.
**Why the Correct Answer is Right**
Expansion of trinucleotide repeats can lead to the disruption of normal gene function, resulting in the expression of abnormally long proteins. This is because the expanded repeat sequence can create a new recognition site for enzymes involved in DNA replication and repair, leading to the preferential amplification of the repeat sequence. For example, the expansion of CAG repeats in the Huntingtin gene is associated with Huntington's disease, a neurodegenerative disorder characterized by the gradual degeneration of neurons in the brain.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a particular type of mutation. While it may be related to the question, it lacks the specificity required to answer the question correctly.
* **Option B:** This option is incorrect because it refers to a point mutation, which is a different type of genetic mutation characterized by a single nucleotide change.
* **Option C:** This option is incorrect because it refers to a chromosomal translocation, which is a type of genetic rearrangement involving the breakage and rejoining of chromosomes.
**Clinical Pearl / High-Yield Fact**
Trinucleotide repeat mutations are associated with a range of neurodegenerative disorders, including Huntington's disease, Fragile X syndrome, and spinocerebellar ataxia. These disorders are often characterized by the gradual degeneration of neurons in the brain, leading to cognitive, motor, and other symptoms.
**Correct Answer: C. Friedreich's ataxia is an example of Trinucleotide repeat mutation.**