Genetics in Cardiology Flashcards Preview

Medicine MD3001 cardiovascular system > Genetics in Cardiology > Flashcards

Flashcards in Genetics in Cardiology Deck (30):

what are Common Cardiology defects in downs syndrome?

atrial septal defect
ventricular septal defect
atrioventricular canal defect
patent ductus arteriosus


what is the overall effect of cardiology defects in down's syndrome?

mixing of oxygenated blood with deoxygenated blood making the system less efficient


what genetic defect causes downs?

trisomy of chromosome 21


how do you find out what causes the heart defects in people suffering from downs syndrome?

look at DNA of people with downs syndrome
see the DNA make up of the chromosome
compare the DNA make up the chromosome with other people who have downs and hence start looking at the genes which cause heart problems


what gene usually predisposes heart defects in people with downs syndrome?

DSCAM on chromosome 21


what are genes DSCAM and COL6A2 involved in?

cell migration and adhesion
involved in causing heart defects in people suffering from downs syndrome


what are there abnormalities caused by 22q11.2 deletion syndrome?

abnormal faces
thymic aplasia
cleft palate


what cardiac abnormalities arise from 22q11.2 deletion syndrome?

tetralogy of fallot
interruption of the aortic arch
ventricular septal defects


how does 22q11.2 deletion syndrome occur?

chromosome 22 has a long range of repeat
DNA recombination can occur in these genes which are repeated
rearrangement occurs: DeNovo, or when we carry the deletion


how does 22q11.2 occur without deletion?

Mutaion on TBX1
can be base substitution- missence
can be deletion of amino acid- nonsense


What is TBX1?

transcription factor
DNA binding factor looking for partner sequences of DNA and can regulate how much mRNA binds to sequence and how much protein is produced from the gene


how does too low or too high TBX1 prevent transcription?

too high- cant find partner combined and cant cause transcription of genes
too low- dimerises to self and inactive dimeric form blocks heterodimer hence still preventing transcription of genes


what is hypertrophic cardiomyopathy?

ticketing of heart walls and inter ventricular septum
the thickness is disorganised, fibrotic as if scarred


how is hypertrophic cardiomyopathy inherited?

autosomal dominant manner
both males and females affected in every generation


what is locus heterogeneity?

defects in more than one gene but still in a single gene


how many different genes cause hypertrophic cardiomyopathy?

11 different genes


how is hypertrophic cardiomyopathy seen on an ECG? what causes this?

-long QT interval
-delay in repolarisation of cardiac cells, mutations in K channels resulting in long QT interval = issue with sodium channel


what do loss of function mutations affect?

can affect the way a portion of a channel is embedded in a membrane
also affect the cytoplasmic loop within the cell


define allelic heterogeneity

different mutations in the same gene all leading to a condition


which channel can be affected by allelic heterogeneity?

KCNQ1 channel and hence cant pump K out of the cell


what is an example of a gain of function mutation?

sodium channel stays open


what is Penetrance?

not everyone with a mutation will have any symptoms


why is it important to identify if individuals have mutations with reference to drugs?

patients with mutations in C-loop then therefore B blockers struggle to reduce complications
if patients have mutations in transmembrane proteins B-blockers will have no effect on these patients


what is familial hypercholesteraemia?

high serum cholesterol in blood
associated with morbidity at a young age
xanthoma- deposits


what is the Simon Broome Criteria for familial hypercholesteraemia?

people have high cholesterol so how to determine if its familial:
studies of extended family
1st degree relative= child share 50% of information with
2nd degree= grandchild 25% of information is shared with


how is familial hypercholesteraemia inherited ?

autosomal dominant manner


describe what a compound heterozygote is

individuals with different mutations causing there disease/condition
when they pass on their genes the individual affected receives different mutations from each individual
hence they are more severely affected
no functioning genes in this pathway


what types of genes are affected in familial hypercholesteraemia?

genes in pathway controlled with removing cholesterol from the blood
LDL-receptor pathway


what is treatment for familial hypercholestermia? what is the issue with this treatment?

once you identify a family member who has the condition you can treat the disorder with statins
-not everyone responds to statins


what is cascade testing?

if a mutation is identified in a family you should then test other members of the family

Decks in Medicine MD3001 cardiovascular system Class (44):