"UVB rays cause sunburn," she says, "UVA rays cause suntan, and both of them contribute to skin damage, skin cancer and DNA mutations, which predisposes to cancer".
Similarly, clinical studies on PINK1 gene mutations, which predispose individuals to PD, showed that, although none of the young heterozygous affected family members were aware of symptoms, they already exhibited unilaterally reduced or absent arm movement or rigidity (Hedrich et al., 2006; van Nuenen et al., 2009).
However, one in 500 people has a maternally inherited genetic mitochondrial DNA (mtDNA) mutation, termed m.1555A>G, which predisposes to extreme idiosyncratic hypersensitivity to aminoglycosides, resulting in permanent and profound deafness.
Similarly, preventive surgery is limited to those with a mutation in E-cadherin, which predisposes to hereditary diffuse gastric cancer (Lynch et al, 2008).
They also tested five healthy women with a family history of breast cancer and mutations on the BRCA1 gene, which predisposes to the disease.
Peutz-jeghers syndrome (PJS) is a rare autosomal dominant disease due to mutations in the tumour-suppressor gene STK11 [62], which predisposes not only to hamartomatous gastrointestinal polyps and mucocutaneous pigmentation, but also to numerous malignancies, including gynaecologic ones, the latter having a reported relative risk of 27.7 % in comparison to the general population [63].
In general, host genetic factors include gene mutations, resulting in an absent or deficient protein, which predisposes for disease.
Disrupted imprinting caused by mutations in the KCNQ1 gene cause Beckwith-Wiedemann syndrome (BWS), which predisposes to cancer [20] [22], and KCNQ1 knockout predisposes to gastric metaplasia [11].
A familial syndrome characterized by germline mutations in PTEN appear to be responsible for Cowden's syndrome, which predisposes to the development of several types of malignant neoplasms, including breast cancer.
