All of the following diseases are caused by trinucleotide repeat mutations affecting non-coding regions except?
A. Fragile X syndrome
B. Myotonic dystrophy
C. Spinocerebellar ataxia
D. Friedreich ataxia
Correct answer : C. Spinocerebellar ataxia
- Fragile X syndrome, Myotonic dystrophy and Friedreich ataxia are examples of trinucleotide repeat disorders with expansions affecting non-coding regions.
- Spinocerebellar ataxia, Huntington’s disease and Spinobulbar muscular atrophy are trinucleotide repeat disorders with expansions affecting coding regions.
Ref: Robbins & Cotran, Pathologic basis of disease, South Asia edition, Vol 1, p168