DNA repair defect is seen in: (A) Xeroderma pigmentosa, (B) Bloom's syndrome, (C) Ataxia telangiectasia, (D) All of these
Answer is D. Examples of DNA repair defects : (1) Xeroderma pigmentosa, (2) Ataxia telangiectasia, (3) Fanconi's anaemia, (4) Bloom's syndrome, (5) HNPCC.