Genetics in Cardiology Flashcards
what percentage of people with Down syndrome have a heart defect
50%
what are the common side effects of Down syndrome
- atrioventricular septal defect
- ventricular septal defect
- atrial septal defect
- patent ductus arterioles
DSCAM and COL6A2 transgenics
- Cell Migration
* Cell Adhesion
CATCH-22
- Cardiac abnormalities
- Abnormal Facies
- Thymic aplasia
- Cleft palate
- Hypothyroidism
Cardiac abnormalities
- Interruption of aortic arch
- Tetralogy of Fallot
- Ventricular septal defect
tetralogy of Fallot
The deoxygenated blood that is returning to the heart from the body (via the superior/ inferior vena cava) is supposed to be re-oxygenated by the lungs (via the pulmonary artery). But, it is not because of the stenosis. Instead, this deoxygenated blood is re-routed back to the body (through the displaced aorta)! Alas, this deoxygenated blood cannot feed the brain the oxygen it needs, the reticular activating can’t function without proper oxygenation and thus it shuts down, resulting in syncope.
DiGeorge Syndrome
22q11.2 deletion syndrome
Why do deletions arise?
- LCR-low copy repeats
- Non allelic homologous recombination
- Mostly de novo rearrangements but can be inherited
Mutations in TBX1
Mostly new mutations. Frameshift-nonsense. Base pair substitution-missense.
Long QT
udden death. Also read about hypertrophic cardiomyopathy.
Locus heterogeneity
mutations in different genes cause same phenotype
mutation sin the KCNQ1 channel - loss of function mutation
not enough potassium goes out of the cell therefore delayed repolarisation
Gain of function mutation - SCN5A Na+ channel stays open
oo much Na+ goes into of cell ie constant depolarisation, makes it difficult to repolarise. Remember that mutations can be both loss of function OR gain ot function.
Familial Hypercholesterolemia
• High concentration of serum LDL cholesterol (total cholesterol>7.5mM)
- Xanthoma
- Atherosclerosis
risk in women of Familial Hypercholesterolemia
30% risk in women before 60 years
