L17 - genetics Flashcards Preview

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Flashcards in L17 - genetics Deck (30):
1

true or false

many renal diseases are inherited even when they only occur in one family member

true

many apparently sporadic diseases are genetic

2

true or false

affected family members DNA is more useful tha unaffected when checking for mutation

false

equally useful

3

Describe Scalp-ear-nipple syndrome?

ectodermal dysplasia

rare AD

renal abnormalities

potentially due to missense mutations in KCTD1 transcription factor

4

An AD disease wilth mutations in TFAP2A causing branchial and periauricular skin defects is....

branchio-oculo-facial syndrome

5

What does TFAP2 control?

expression of keratin, collagen - explains skull defect, thinned membrane and astigamatism

6

What is a missense mutation?

where one AA is replaced by another

- can build up in ER and cause ER stress

7

What is a nonsense mutation?

is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and in a truncated, incomplete, and usually nonfunctional protein product.

8

Describe the CRISPR technique

used to target and correct mutation

cuts out the mutationa dn provides a template of normal DNA that can be copied

1. desig ss DNA oligonucleotides
2. Anneal ss oligos to generate ds oligo
3. dilute to working concentration
4. clone to nuclease vector
5. transform e.coli cells and select for expression
6. Analyse transformants for insert by sequencing
7. Prepare purified plasmid DNA and transfect patient fibroblasts

9

True or false

you need a monoclonal population of cells for the CRISPR technique

true

10

True or false

the mutations tha cause disease are often difference between each family which makes gene editing labourious and not as good

true

also risks of transfected cells

11

Future treatments for genetic dieases will..

be a cocktail of treatments

directed against underlying mutation

12

True of false

humans have much less non-coding sequences than other animals

false

much more

13

Mitochondrial DNA mutations often affect ___

muscles

increase mutations with ageing

14

about _% of RNA is messenger RNA

3%

the rest is ribosomal RNA

15

Often families too ____to work out the inheritance pattern of disease. Families may not know of other _____ family members - take alot of ___ to ask around

Often families too small to work out the inheritance pattern of disease. Families may not know of other affected family members - take alot of time to ask around

16

why is it important to do pedigree analysis?

to give genetic counselling to family members

identify novel genes for inherited disease

17

There are at least _ different genes involved in colour blindness

18

18

How is intelligence inherited?

5 themes of intelligence - 3 on X chromosome

No transmission from father to son

controversial but generally true

19

true or false

There are at least 8000 inherited diseases. Sometimes mutations in the same gene can cause different mutations. Most of us have 5 significant mutations

true

20

What is imprinting?

when the maternal or paternal chromosomal region behave differently

e.g prader willi syndrome

21

What has an increased risk with IVF and why?

Beckwith Wiedeman and angelman syndromes

loss of methylation of maternal chromosomes

22

What is locus heterogeneity/

mutations in different genes causing the same disease

23

what is allelic heterogeneity?

different mutations in a gene causing different diseases

24

What is copy number variation and where is it important?

variation in the number of copies of gene or DNA sequence

probably important in autism and schizophrenia

25

What are genome-wide association studies?

large studies that identify multiple variants each with small effect on risk of diseases

risk of false-positives tho - need to confirm with independent populations

26

85% of disease causing mutations are in ____ which make up _% of the genome

exomes - 1% of the genome

27

true or false

genes for many rare diseases are still unknowm

true

28

What is gene discovery based on?

shared haplotypes (a group of genes within an organism that was inherited together from a single parent.)

uses multiple bioinfromatics steps

pathogenic varient then identified

confirm by demonstrating variants in other families with same condition

29

Name some drugs where prospective genotyping/phenotyping may be useful

antidepressants
Warfarin
Perhexiline
Proton pump inhibitors

30

Why test for mutations/

Diagnosis

genotype-phenotype correlations and predicting clinical outcome

treatments will be tailored to mutation type