Genetic counselling Flashcards
what is genetic counselling
helping people understand and adapt to the implications of genetic disease
family and medical histories
education about inheritance
counselling to promote informed choices
what is the carrier frequency of cystic fibrosis
1 in 23
what is the newborn screening programme for CF
heel prick immuno reactive trypsinogen level
test for CF mutations
CF confirmed if 2 mutations are found
what is G551D mutation
a confirmed pathogenic CF mutation
what is R117H
a mild mutation in a small number of CF patients
makes up 10% of CF mutations identified
most heterozygotes with R117H do not have CF
the effect is dependent on intron 8 splice efficiency
5Ts is bad if found with R117H
describe the genotype-phenotype correlation
disease ranges from asthma modifier to CF syndrome to full CF with or without pancreatic insufficiency
depends in genotype- number and type of gene modifications
what is werdnig-hoffman disease
spinal muscular atrophy
recessive condition
anterior horn cell degeneration
floppy, breathing and eating problems
what gene is responsible for spinal muscular atrophy
SMN1 survival motor neurone 1
How many generations should be analysed
3
what is allele drop out
false negative due to failure to amplify a mutation
what are the questions that post termination genetic counselling attempts to answer
was the diagnosis confirmed why did it occur can we ever have a baby what tests are available in a future pregnancy did we make the right decision
how can you determine whether a mutation is the cause of a disease
look at literature
has the mutation already been described?
look at an unaffected population cohort
run programme to look at gene conservation across species
what are the issues to consider in presymptomatic testing
is there preventative treatment patient must be fully informed health insurance employment relationships
