Mendelian Inheritance COPY COPY COPY Flashcards
What do disease associated mutations do
Alter protein function as it will have a non functioning or missing protein
What causes sickle cell disease
Abnormal HB gene
What type of inheritance does sickle cell disease show
Autosomal recessive
Where is sickle cell disease most prevalent
Africa
Mediterranean
Middle-East
India
What does SCD do to RBCs
Causes them to become sickle shaped which causes pain, tissue damage,infection and even death
What kind of problems can SCD cause
Problems with anaesthesia
Also: severe pain, cold, dehydration, infections, jaundice, stroke, leg ulcers, eye problems and kidney problems
In a family pedigree what shape are the boys
Square
In a family pedigree what shape are the girls
Circle
What is it called hen there is a risk of 0
Population risk
What is the chance of having a carrier child when the mother and father are both carriers of an autosomal recessive disorder
1/2 (50%)
What is the chance of having an affected child when the mother and father are both carriers of an autosomal recessive disorder
1/4 (25%)
What is the chance of being a carrier when your mother and father are both carriers of an autosomal recessive disorder and you know you do not have the disorder (e.g. 23 years old and have no symptoms of the disease)
2/3 (66%)
What is the chance of being a carrier when the mother and father are both carriers of an autosomal recessive disorder and you know you do not have the disorder (e.g. 23 years old and have no symptoms of the disease)
2/3 (66%)
What is the chance of being unaffected when your mother and father are both carriers of an autosomal recessive disorder and you know you do not have the disorder (e.g. 23 years old and have no symptoms of the disease)
1/3 (33%)
What is the chance of having a carrier child when only one parent is a carrier of an autosomal recessive disorder
50%
What is the chance of having an unaffected child when only one parent is a carrier of an autosomal recessive disorder
50%
What is the chance of having an affected child when only one parent is a carrier of an autosomal recessive disorder
0%
What can CF affect
Sinuses Lungs Skin Liver Pancreas Intestines Reproductive organs
What happens to the airways in CF
Airway walls tend to have thick, sticky mucus which blocks the airway and they may have bacterial infections and blood in their mucus
What is the chance of a child being a carrier if the grandparents are both carriers (and mother is definitely unaffected) and the father is from the UK where there is a 1/25 chance of being a carrier
The child’s mother’s chance of being a carrier is 2/3
The child’s father’s chance of being a carrier is 1/25
So the chance of both of them being a carrier is 2/3 x 1/25 = 2/75
So the child’s chance of being a carrier is 2/75 x 1/4 = 1/150
The child’s chance of being a carrier is 1/150
What is the chance of a child being a carrier if the grandparents are both carriers (and mother is definitely unaffected) and the father is from the UK where there is a 1/25 chance of being a carrier
The child’s mother’s chance of being a carrier is 2/3
The child’s father’s chance of being a carrier is 1/25
So the chance of both of them being a carrier is 2/3 x 1/25 = 2/75
So the child’s chance of being a carrier is 2/75 x 1/4 = 1/150
The child’s chance of being a carrier is 1/150.
What is the chance of a child being a carrier when the child’s maternal cousin (mother’s nephew) has CF
The child’s mother chance of being a carrier is 1/2 (as she either is a carrier or not and she definitely does not have the disease)
The child’s father is ignored in this situation as it is very unlikely he has the disease
So the child’s chance of being a carrier is 1/2 x 1/2 = 1/4
What is the chance of having a carrier child when the father is a carrier of an autosomal dominant disorder
1/2 (50%)
With autosomal dominant disorders can there be skipped generations
No
