Lecture 6 Flashcards
autosomal recessive inheritance
manifested when you have an alteration in both copies of the gene
if both parents carry an autosomal recessive disorder what is the chance of the child being affected
1 in 4
if a child is not affected what is the chance of them carrying the condition
2 in 3
pseudodominant inheritance
Since both parents carry the recessive allele, there is a 25% chance with each pregnancy that their child will inherit two copies of the recessive allele and therefore exhibit the trait.
The trait is then expressed in multiple generations of a family, resembling dominant inheritance even though the trait itself is recessive
autosomal recessive disorder in Western Europe
cystic fibrosis
autosomal recessive disorder in West Africa
sickle cell anaemia
autosomal recessive disorder in Middle and Far East
thalassaemia
sickle cell anemia
red cells becomes more fragile and break up
blockage of small blood vessels with fragmented red cell
Thalassemia
autosomal recessive disorders with chronic anemia
alpha thalassaemia
underproduction of alpha globin from the alpha globin gene cluster on chromosome 16
- common in south East Asia
Beta Thalassaemia
underproduction of beta globin from the beta globin gene on chromosome 11
- common in Mediterranean
Cystic Fibrosis
thick mucous secretions in lungs, digestive system and pancreas
what is the frequency of cystic fibrosis in Ireland
1 in 1600
damage done to lungs in Cystic Fibrosis
large volumes of infected sputum, chronic infection with damage to bronchi and fibrosis of lung
damage done to digestive system due to cystic fibrosis
blocked pancreatic ducts
failure to absorb food
in infants - blocked bowel due to thickened meconium
