Table 1.

Diseases and disorders associated with defective DNA repair.

DNA Repair Mechanism	Associated Disease/Disorder	Mutation/Deficiency Responsible	Clinical Presentation
Mismatch repair	Lynch syndrome Constitutional mismatch repair deficiency syndrome	MSH and MLH mutations [103]	Colorectal cancer, endometrial cancer [103]
Nucleotide-excision repair	Xeroderma pigmentosum disorder	Mutations in xeroderma pigmentosum complexes [104]	Neurodegeneration, photosensitivity, skin cancer [104]
Base-excision repair	Spinocerebellar ataxia with axonal neuropathy (SCAN1) Ataxia with oculomotor apraxia 1 (AOA1)	Tyrosyl-DNA phosphodiesterase deficiency [105] Aprataxin deficiency [106]	Ataxia, neurodegeneration [105,106]
DNA damage response (DDR)	Li-Fraumeni syndrome	p53 mutation [107]	Soft tissue sarcomas, breast cancer, brain tumours [107]