Mendelian Inheritance Flashcards
What do disease-associated mutations alter?
Protein structure and thus function
How many babies are born with sick cell disorders in UK?
1/2500
What is gene in affect and what does it cause in sickle cell disorders?
Abnormal haemoglobin gene and cause RBC to become sickle-shaped, causing pain, tissue damage, infection and death.
What genes do carriers have?
One functioning gene and one non/partially functioning gene
If both parents are carriers, and their sibling is affected, what is the chance of someone being a carrier?
2/3
If one parent is a carrier and the other a non-carrier, what is there chance of child being a carrier?
1/2
What disorder results in carriers of condition to be less prone to getting malaria?
Sickle Cell
How many people are carriers for cystic fibrosis in UK?
1/25
What type of gene mutation is cystic fibrosis?
Single gene
If one parent is a carrier of cystic fibrosis, what is the fraction of them having a baby which is affected?
1/100
1 in 4 chance of child getting it, times 1 in 25 chance of having cystic fibrosis
What is achondroplasia?
Autosomal dominant disorder where an abnormality in one of the genes produces an abnormal protein, upsetting growth of bone
If you know that one sibling is a carrier for a recessive genetic disorder (i.e. CF) what is chance of sibling being a carrier if they dont express condition?
1/2 (parents either FFxFf or FfxFf)
In autosomal dominant disorder what is the chance of child being affected if one parent has disorder and one parent doesn’t?
1/2
Can a person be a carrier for a dominant condition?
No, as dominant allele expresses condition - unaffected child must have double recessive gene
Principles of autosomal dominant inheritance?
- 1/2 chance of inheriting
- No skipped generation
- Equally transmitted by men and women (male to male transmission)
