inherited disorders

• what is polydactyly?

  an inherited disorder caused by a dominant allele so it can be passed on when only one parent has the disorder. this condition means extra fingers or toes are present.
• what is cystic fibrosis?

  an inherited disorder caused by a recessive allele. it affects cell membranes across the body
• screening of the embryo can be completed from 10 weeks of pregnancy but there is a risk of miscarriage
• how does embryo screening happen?

  a fine needle is passed through the abdomen into the uterus and a small piece of the developing placenta is removed. This is analysed to see if alleles that cause polydactyly or cystic fibrosis are present.

  This testing is usually only done when there is a family history of the disorder.

  Screening is costly and not 100% reliable.
• • Embryos can be screened for parents undergoing IVF.
  • the egg and sperm are mixed and fertilisation occurs in a laboratory. usually several embryos are produced.
  • the embryos are then screened. any embryos which have the faulty alleles are not implanted into the mothers uterus.
  • only healthy babies will be born.
• what is gene therapy?

  replacing the faulty allele with a normal allele.

  This cant be done to gametes so can only occur in an individual who already has inherited the disorder.

  gene therapy is still being researched and is not always successful.

  it is also expensive
• gene therapy and embryo screening can be used to alleviate suffering but it is important to consider the ethical issues of these techniques
• Economic, social or ethical issues

  may cause a miscarriage

  if embryo has a disorder should they get an abortion

  is it right that only healthy embryos are implanted in IVF

  should screening be available to everyone, not just those who can afford it or have the disorder in their family history

  what if the test result is wrong