Gene to Function to Clinic Flashcards
who was mary-claire king
famous for identifying breast cancers
what is the average female risk of developing breast cancer and what genes affect this
12% normal risk
BRCA1/2 increases risk to 85% and increase overran cancer risk (more so by BRCA1 than 2)
what are the advantages of testing for BRCA mutation
relief of knowing
women respond better for treatment designed for people who are BRCA positive
may take preventative measures knowing they have a higher risk
may encourage other family members to get tested
what are the disadvantages of BRCA testing
may worry people and after life and increase risk
difficulty of telling family members
may give false hope of not getting cancer as they are BRCA negative
positive people have to deal with increases in insurance
why is prophylactic surgery beneficial in cancer
remove ovaries after family - reduces risk by 85%
preventative mastectomy - reduces risk by 90%
what is presymptomatic screening used for
for late onset disorders such as Huntington’s, cancers or retinitis pigmentosa
predict but can’t prevent
why is diagnostics and counselling important in cancer screening
confirm clinical diagnosis
identify carriers of recessive mutations
identify cases of non-penetrance
what are the types of prenatal diagnosis can occur
amniocentesis - 17 weeks
chorionic villus smapling - 11 weeks
NIPD - 10 weeks (maternal serum contains foetal DNA)
describe preimplantation diagnosis
biopsy taken from each embryo before implantation and only the unaffected embryos are implanted
what is classic gene therapy
introduction of functional genes in the from of DNA to replace mutated genes
how is gene therapy used to treat lebers congenital amaurosis (LCA)
rare inherited eye disorder
caused by RPE65 mutation (affects transduction)
sub retinal injection with adenoassocited virus containing RPE65 and promoter been shown to restore in canine model
what is CRISPR
new method of gene editing allowing replacement of mutated gene
what is the most important enzyme in the liver asosicted with converting drugs to their active from
cytochrome P450 oxidases
describe the polymorphisms of CYP2D6
metabolises 25% of drugs
6-10% caucasians are non metabolises ie no active CYP2D6
7% of caucasians are ultra rapid metaboliser ie multiple copies of CYP2D6
how do cyp2d6 polymorphisms affect tamoxifen
poor metabolisers due to weak cyp2d6 have less conversion to the active endoxifen and have worse survival rates
