Inherited diseases

• Cystic fibrosis is a disorder that affects plasma membranes

  This is a genetic disorder caused by a recessive faulty gene
• • Polydactyly is a congenital condition characterized by having more than the usual number of fingers or toes on the hands or feet.
  • Polydactyly is caused by a dominant allele, meaning that only one copy of the gene from either parent is needed to express the trait.
  • Surgical intervention may be considered to remove or correct the extra digits, depending on the severity and impact on function.
  • Individuals with polydactyly can lead normal, healthy lives, and the condition may not necessarily cause any functional impairment.
• • Cystic fibrosis and polydactyly are genetic disorders
• • Cystic fibrosis is caused by a recessive allele which means two copies are required for it to be expressed
  • It causes mucus to be too thick causing issues with breathing, digestion and reproduction
• • Polydactyly is caused by a dominant allele, which means only one copy is required for it to be expressed
  • It causes an extra digit to be present on fingers or toes
• Genetic tests are now available to test the DNA of cells. These tests can show people if they carry a faulty allele which could cause a genetic disorder. This is called genetic screening
• It is also possible to screen embryos and foetuses during pregnancy for the alleles that cause inherited disorders.
• Embryos can also be screened before they are implanted in the mother during in vitro fertilisation (IVF) treatment.
• What is one alternative for couples with an inherited disorder?

  Testing embryos produced by IVF
• Why do couples test embryos before implantation?

  To ensure only healthy babies are born
• What choices do parents have if a fetus is affected by a genetic disorder?

  Keep the baby or have an abortion
• What is the purpose of having an abortion in this context?

  To prevent the birth of a child with serious problems
• What can parents do after deciding not to keep an affected fetus?

  Try again to have a healthy baby
• What is pre-implantation embryo screening used for?

  Avoiding another affected pregnancy
• What are the steps involved in embryo testing before implantation?

  • IVF is performed to create embryos
  • Embryos are tested for genetic disorders
  • Only healthy embryos are implanted
• The processes used to collect cells from a developing fetus increase the risk of miscarriage. So, in some cases, a healthy fetus will be miscarried as a result of a test to see whether it has a genetic abnormality, which is obviously very distressing for the parents.
• The screening procedures can give a false positive or a false negative result. This can lead to the termination of a healthy pregnancy or the unexpected birth of a child with a genetic disorder.
• Embryo screening also means that people have to make decisions about whether or not to terminate a pregnancy. This is never an easy decision.
• Each couple, faced with the knowledge that their embryo is affected by a genetic disorder, makes their decision based not only on their scientific understanding of the situation explained by their doctors, but also on their emotions and their own ethical framework and religious beliefs.
• Screening is expensive. Some people think everyone should have the tests regardless of the cost. If a couple have a child affected by a genetic disorder it can be very costly for society to provide health care and support for the family.
• Some people are concerned that genetic screening could give rise to a demand for 'designer babies'. This would occur if parents used genetic screening to choose children with 'desirable' characteristics, such as a particular sex, good looks, or intelligence.