Genetics and sudden death Flashcards
What is penetrance?
The likelihood of having a disease if you have a gene mutation
If you have a gene mutation with 100% penetrance, what would that mean?
It means you will always get the disease if you have the mutation
Describe Mendelian disorders
Essentially a disease that is predominantly caused by a change in a single gene (high penetrance)
If there was a mutation in the exon part of the gene, what are the 4 possible consequences?
Potential to change 1) change to an amino acid sequence 2) or create stop 3) or cause frameshift 4) or have no effect
What is the cDNA sequence?
The mature mRNA sequence with the introns removed, referenced to the first base of the first codon
Describe this mutation, SMAD4:p.Cys162Ter
The cystine in the peptide sequence of SMAD4 at position 162 has mutated to a stop codon
Describe this mutation, SMAD4:c.471A>T
The adenine in position 471 in the cDNA sequence has mutated to a thymine
What is the mode of inheritance in dissecting aortic aneurysm?
Autosomal dominant (sporadic) - ACTA2 gene accounts for 10% of cases
List some features of Marfan’s syndrome
Tall and slim, disproportionately long arms, legs and fingers, protruding sternum either outward or dips inward, a high, arched palate and crowded teeth, heart murmurs, extremely short sighted, curvature of the spine and flat feet
What is the likely mutation causing Marfans syndrome?
Fibrillin gene mutation
List some features of Loeys Dietz syndrome
Bifid uvula, widely spaced eyes, strabismus and cleft palate
What mutation causes Loeys Dietz syndrome?
Mutations in TBR1 or TBR2
What does next generation sequencing allow?
Analysis of large panels of genes
What is the prevelance of a high penetrance genetic cardiac disease?
1 in 200 (at least)
