Pedigrees and risk Flashcards
Basic Symbols
Why do we draw pedigrees
Spot patterns
Simple sumpary
Explain pattern to patient
Calculate risk
Identify potential carriers
Why not test for the disease
Causative gene isn’t known
Sporadic disease
Some people don’t want to know
Impossible to test every one for disease
What is amyotrophic lateral sclerosis
Motor neurone disease
85% sporadic
Steps to draw a pedigree
Start at the bottom
Choose one parent
Add other side of family
Ask about children and partners
What are some potential difficulties with pedigree diagrams
Incomplete information
Family history may not be correct
Incorrect information
What is the heterozygote advantage
Sickle cell
CF?
What is hereditary haemochromatosis
Excess iron absorption which builds up in tissues
Tiredness
Only 10% have clinically relevant iron accumulation
