inherited disorders - part 1

many of these disorders can be screened for in embryos! - cystic fibrosis - sickle cell anaemia - huntington's disease - polydactyly

what is cystic fibrosis?

• recessive allele disorder

• genetic disorder of the cell membranes

what happens when you have cystic fibrosis?

• breathing difficulties

  • mucus in the air passages

• digestion difficulties

  • mucus in pancreas

• chest infection

• stomach problems

will all people with the allele have cystic fibrosis?

• as it is recessive, only people with two copies of the allele will have cystic fibrosis

• people with one copy will be unaffected and are carriers

when will a child have cystic fibrosis?

• both parents are carriers

• parents have cystic fibrosis

what is polydactyly?

dominant allele disease

• so can be inherited if just one parent carries the defective allele

what happens when you have polydactyly?

born with extra fingers and toes (not life-threatening!)

what is Huntington’s disease?

dominant allele disease

• so can be inherited if just one parent carries the defective allele

what happens when you have Huntington’s disease?

• loss of control/co-ordination

• loss of cognitive ability

  • thinking, memory

• death

(symptoms don’t appear until 35-45)

what is sickle cell anaemia?

• incomplete dominant allele

• red blood cells are sickle-celled

  • abnormal haemoglobin = can’t carry oxygen

how is a person affected if they have SS alleles (sickle cell)?

• normal red blood cell

• no malarial resistance

how is a person affected if they have Ss alleles (sickle cell)?

• red blood cell slightly sickle celled

• person mostly healthy

• malarial resistance

how is a person affected if they have ss alleles (sickle cell)?

• normal red blood cell

• no malarial resistance