This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Trinucleotide repeats found ina) Huntigton's diseaseb) Spinocerebellar ataxiac) Amyotropic lateral sclerosisd) Sclerosis 
Select and explain. 
A. ac, B. a, C. ad, D. ab
D: ab
Answer: D: ab 
Explanation: Examples of trinucleotide repeat mutation :-


Huntignton's disease      
Spinocerebella ataxia 
Friedreich ataxia      
Fragile - X-syndrome
Dystrophia myotanica
Dentorubral pallidoluysiane atrophy
X-chromosome spinobulbar muscular atrophy