CTG trinucleotide repeat disorder is associated with which gene?

CTG trinucleotide repeat disorder is associated with which gene?

• A. DMPK gene
• B. HTT gene
• C. FMR1 gene
• D. MYOD1 gene

Answer: (A)

CTG trinucleotide repeat disorder is specifically associated with the DMPK gene, which stands for Dystrophia Myotonica Protein Kinase gene. This gene is linked to Myotonic Dystrophy Type 1 (MD1), one of the most common forms of muscular dystrophy. The disorder arises when there is an expansion of a CTG trinucleotide repeat in the 3' untranslated region of the DMPK gene. In Myotonic Dystrophy Type 1, the normal number of CTG repeats is small, but as individuals age or through inheritance, the number of repeats can expand, leading to symptoms such as myotonia (delayed relaxation of muscles), muscle weakness, and multisystem involvement. This makes it distinct from other trinucleotide repeat disorders. The other genes listed are associated with different disorders: the HTT gene is associated with Huntington's disease (CAG repeat expansion), the FMR1 gene is linked to Fragile X syndrome (CGG repeat), and the MYOD1 gene is involved in certain types of muscular dystrophy but not in relation to CTG repeats. Understanding the specific associations of each gene with their respective disorders helps in accurately diagnosing and managing these conditions.

CTG trinucleotide repeat disorder is specifically associated with the DMPK gene, which stands for Dystrophia Myotonica Protein Kinase gene. This gene is linked to Myotonic Dystrophy Type 1 (MD1), one of the most common forms of muscular dystrophy. The disorder arises when there is an expansion of a CTG trinucleotide repeat in the 3' untranslated region of the DMPK gene.

In Myotonic Dystrophy Type 1, the normal number of CTG repeats is small, but as individuals age or through inheritance, the number of repeats can expand, leading to symptoms such as myotonia (delayed relaxation of muscles), muscle weakness, and multisystem involvement. This makes it distinct from other trinucleotide repeat disorders.

The other genes listed are associated with different disorders: the HTT gene is associated with Huntington's disease (CAG repeat expansion), the FMR1 gene is linked to Fragile X syndrome (CGG repeat), and the MYOD1 gene is involved in certain types of muscular dystrophy but not in relation to CTG repeats. Understanding the specific associations of each gene with their respective disorders helps in accurately diagnosing and managing these conditions.