Genetic Testing

Make a list of all the genetic tests babies

get (you will probably have had

these!)

Genetic screening

All babies in the UK are screened for the following:• Hypothyroidism• Cystic fibrosis• Phenylketonuria (PKU)• Medium-chain acyl-coenzyme A

dehydrogenase deficiency (MCADD)• Sickle-cell disease (only in families at risk)

Genetic Screening

• Lesson Learning Outcomes:

Increasing Difficulty

Describe the process of

PGD

Suggest what PGD might be used for.

Consider the ethical

implications of genetic screening.

What is genetic screening and is it ethical?

IVF

• What do you know about IVF?

Genetic Screening

• Video 1• Video 2

• Watch these video clips

• What might we use PGD for?

Sorting Time

• Put the cards into the correct order.

• In your books turn this into a cartoon that shows how PGD is carried out

Uses of PGD• Spider diagram what it might be used for and

what some of the consequences of its use might be!

Uses of PGD

Video Time!

• Video 3

• When you are watching this video make notes on:– What is it?– Why you might get it done?– What are the risks?– What are the potential ethical outcomes?

Rainbow Groups• PICK A COLOUR• Find out some information about genetic

screening

Share Time

• Share the information you have found out

Work in Pairs

• Answer the following question:

• Do you agree or disagree with the genetic testing of newborn babies and the setting up of a DNA database? Explain your reasons.

Drugs and Genetic Screening

• In 2009 Carolyn Major started to take the medicine she hope would cure her cancer. Instead, four days later; she was in an intensive care ward with her heart struggling to keep going. She is one of a small group of people whose bodies react very badly to the anti cancer drug. Carolyn was lucky, She recovered with no permanent damage done to her heart and so far the cancer hasn’t returned either.

• In the future the genetic testing of adults may make problems like this a thing of the past. Doctors think they can use genetic tests to match medicines to some patients. Some people produce enzymes that break down drugs very quickly, so they need higher doses of a medicine than most other people. Other people don’t produce enzymes to break down certain drugs in their body so they can be poisoned by medicine that is meant to help them. In the future, genetic testing may show if people have the genes for these enzymes so we can all be given the drugs that work best for our bodies’ genotype

Screening a Foetus• If a couple know they are at risk of having a child with a genetic disorder

such as cystic fibrosis they can have tests to see if their child has the disease. During pregnancy cells from the developing foetus can be collected and the genes examined. This can be done in two ways:– Amniocentesis Test – where a needle is used to withdraw some amniotic fluid

from the mothers uterus. This fluid contains foetal cells. This test is carried out at 15 – 18 weeks. There is a 1% miscarriage risk and a very small risk of infection

– Chronic Villus Test – where a suction tube is inserted into the uterus through the cervix. It is used to remove cells from the placenta. This test is carried out at 10 -12 weeks. There is a 2% chance of miscarriage and almost no risk of infection.

• The results from both of these tests are not 100% reliable. • If the foetus has inherited two recessive alleles for a recessive genetic

disorder or one dominant allele for a dominant disorder the child will have the disease. The parents may choose to end the pregnancy. This is done with a medical operation (a termination or abort)

Genetic Screening• Testing the whole population for a genetic disorder is called genetic screening.

This is now done in the UK with some genetic disorders such as cystic fibrosis, this allows the NHS to start treatment for these genetic disorders early. This means that they extend the lives of people suffering from genetic disorders.

• The decision about whether or not to carry out genetic screening is taken by governments and local NHS trusts. People in the NHS have to think about different things when they decide if genetic screening should be used including: the costs of testing everyone, the benefits of testing everyone, could the money be better spent on other things and benefit more people.

• CASE STUDY: Four of Rabbi Joseph Ekstien’s children died from a severe genetic disease called Tay-Sachs disease. In the general population one baby in every 300 000 has Tay-Sachs disease but in the 1980s one baby in every 3600 born to European Jewish families was affected and died. In 1983 Rabbi Ekstein set up a genetic screening programme. Couples planning to marry were genetically tested. If they both carried the recessive allele they were advised either to not marry or to have prenatal screening and terminate effected pregnancies. As a result of this genetic screening Tay-Sachs has almost disappeared from Jewish communities.

Who should know the results?• Insurance companies assess what a persons risk is of dying earlier than average.

If they believe the risk is too high they may choose to charge higher premiums than average. Some people think that insurance companies might use the results of genetic tests in the wrong way. Individual people might do the same. But having a gene that means you have a higher risk does not mean that you will definitely die earlier. People are concerned that insurance companies might start charging higher premiums, they may say that everyone must have genetic tests or they might feel they have to keep the results of their genetic tests secret.

• Scientists already use information about people’s DNA to help them solve crimes. They produce DNA profiles from cells left at a crime scene. There is usually only 1 in a 50 million chance of two people having the same DNA profile (excluding identical twins)

• Some people think there should be a national DNA database recording everyone living in the country. If all the babies were to have their genome sequenced at birth, this will easily be available in the future. Human right’s campaigners are against a database for everyone’s DNA. They think it is an invasion of privacy and puts innocent people on the same level as criminals