Disease Symptoms Genetic Defect
Xeroderma pigmentosum Frecklelike spots on skin, sensitivity to sunlight, predisposition to skin cancer Defects in nucleotide-excision repair
Cockayne syndrome Dwarfism, sensitivity to sunlight, premature aging, deafness, intellectual disability Defects in nucleotide-excision repair
Trichothiodystrophy Brittle hair, skin abnormalities, short stature, immature sexual development, characteristic facial features Defects in nucleotide-excision repair
Hereditary nonpolyposis colon cancer Predisposition to colon cancer Defects in mismatch repair
Fanconi anemia Increased skin pigmentation, abnormalities of skeleton, heart, and kidneys, predisposition to leukemia Possibly defects in the repair of interstrand cross-links
Li-Fraumeni syndrome Predisposition to cancer in many different tissues Defects in DNA damage response
Werner syndrome Premature aging, predisposition to cancer Defect in homologous recombination
Table 18.6: Genetic diseases associated with defects in DNA-repair systems