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: Pathology
The following diseases have a defect in DNA repair mechanism except for 
Select and explain. 
A. Xeroderma pigmentosum, B. Huntington’s disease, C. Fanconi syndrome, D. Hereditary non polyposis colon cancer
B: Huntington’s disease
Answer: B: Huntington’s disease 
Explanation: Inherited autosomal recessive syndromes of defective DNA repair
Ataxia Telangiectasia
Bloom syndrome
Fanconi anaemia
Xeroderma pigmentosum
Hereditary Nonpolyposis cancer
Huntington’s disease is an example of trinucleotide repeat disorders