Inheritance Flashcards
Features of autosomal dominant inheritance
Affected people in each generation
Males and females
All forms of transmission incl male to male
Risk of inheritance in autosomal dominant
50%
Variable penetrance (likelihood disease manigest if gene change present)
Autosomal recessive inheritance features
Cant always follow disease through pedigree
Males and females affected
Risk of inheriting recessive disease if parents are carriers
25% if both parents carriers
50% - carrier but inaffected
25% chance not carrier or affected
Children of affected parent risk of carrying disease
100% - all children of affected individual will be carriers
Risk of siblings of affected individual being a carrier
2/3
Why do X linked conditions affect men
Women have two X chromosomes - other allele makes up for it
Clues in x linked recessive inheritance
More than one generation affected
Only males effected
No male to male tranmission - males dont pass chromosome to their son
Risk of disease inheritacne X linked recessive
25% risk affected male in each pregnancy
Risk of unaffected male per pregnancy X linked
25%
Risk of unaffected male each pregnancy X linked
25%
Chances of non carrier female without condition
25% chance
Risk of carrier daughters and sons
50% risk
What is important to ask in a family history of genetics
Relationship breakdonw - divorce/estrangement
Adoption/other biological relationships/non paternity
Causes of daeth other than natural eg accidental, suicide, drug/alcohol related
Bereavment incl miscarrigae and abortion
Consanguinity - incest
What is a genomic test types
Analysis of DNA
Diagnostic - Test which seeks to confirm a clinical diagnsois
Predictive - test offered to relatives of someone confirmed genetic cancer