Lecture 16: Gene - Function - Clinic Flashcards
What does gene identification allow for?
): the occurrence in members of a population of combinations of linked genes in non-random proportions
What percent of mutation are only responsible for what percent of familial cancers?
16%
Account for 5-10% of all breast cancers
In the USA what percent is a woman likely to get breast cancer?
12%
What percent does the BRA1 or BRA2 gene increase the risk of breast cancer by?
85%
Give 3 advantages of testing for the BRCA genes in women?
1) women may take preventative measures to help reduce risk of breast cancer
2) other family members may decide they wish to be tested for BRCA
3) women with breast cancer may have better responses to certain treatments that are specifically designed for BRAC positive patients
Gove three disadvantages of testing for the BRCA genes in women?
1) women may have difficulty telling their family members
2) women who test positive for BRCA mutations may falsely believe they will never get breast cancer
3) positive tests may cause complications with life insurance
Other than breast cancer, give three other diseases that presymptomatic testing can be used for:
1) Huntington’s
2) retinits pigmentosa
3) colon cancer
What is the name of the new prenatal diagnostic technique used at week 10?
NIPD (non-invasive prenatal diagnosis)
How does NIPD work?
placental DNA in the maternal serum is NGS genome sequenced to identify trisomies
Give three types of prenatal diagnosis:
1) NIPD
2) chorionic villus sampling
3) aminocentesis
What week would chorionic villus sampling take place?
11 weeks
What week would amniocentesis take place?
17 weeks
Which body oversees preimplantation diagnosis?
the Human Fertilisation and Embryology
Describe how ‘saviour siblings’ can be created from preimplantation diagnosis:
human leukocyte antigens can be selected to match cord blood stem cells for siblings
What is preimplantation genetic diagnosis?
allows detection of genetic abnormalities prior to implantation
What is non-disclosure?
where a mother wants to know if her child will be affected by a genetic disease but does not want to know if she is at risk
What is precision therapy?
a strategy that integrates molecular information with clinical data to select the best therapeutic intervention
What is gene therapy?
the use of genetic material (DNA or RNA) as medicine
When is gene therapy used?
often to replace mutated genes, silence overactive genes or provide our immune cells with the tools they need to recognise and kill cancer cells and infections
What is the name of the rare inherited eye disorder associated with the RPE65 gene?
Leber’s congenital amaurosis
True or false: Leber’s congenital amaurosis causes blindness
true
Does Leber’s congenital amaurosis follow a dominant or recessive inheritance pattern?
recessive
What gene is associated with Leber’s congenital amaurosis?
RPE65
What does RPE65 gene produce?
protein involved in phototransduction
Describe the gene therapy used to cure Leber’s congenital amaurosis:
a sub-retinal injection between photoreceptors and retinal pigment epithelium containing adeno-associated virus containing human RPE65 and human RPE65 promoters is given
What is CRISPR?
editing a gene with a specifically designed synthetic guide molecule after cutting defective target DNA out of the strand
What is pharmacogenetics?
the correlation between the effect of drugs and the genetic constitution of patients
What are cytochrome P450 oxidases?
a family of enzymes found predominantly in the liver responsible for the metabolic elimination of most drugs and converting pro-drugs into their inactive forms
Describe CYP2D6 as an example of pharmacogenetics:
Some people have very active CYP2D6 genes while others done and having poor CYP2D6 activity is associated with worse survival when using tamoxifen so now genetic testing for CYP2D6 polymorphisms are carried out privately
What is the role of CYP2D6?
It is involved in the rate determining step in converting tamoxifen to its active metabolite endoxifen
What is the name of the branch of preventative medicine where clients can be tested for multiple different genes associated with diseases?
Direct-To-Consumer testing
