Injecting DNA into a cell

Whose rights? Genetic testing before birth

Genetic advances have great potential for improving health, but they also raise questions about privacy and who should have access to personal information such as genetic data. Take a look at the made-up scenario below to explore issues that are far from black and white

Parents who are worried about their children inheriting harmful mutations now have several options. Prenatal genetic testing can be used to detect mutations in an embryo or fetus that are linked to particular conditions. Using in vitro fertilisation, it’s also possible to create and select embryos that don’t have the harmful mutations. Read the text below and study our imaginary headlines, then see what you think about the questions that follow.

Prenatal genetic testing

Alternative headlines: Prenatal test for autism would deprive world of geniuses; Gene test hope for autism
CC BY

‘Big Picture: Genes, Genomes and Health’ (2010)

Parents at high risk of having a child with a genetic condition will be given genetic counselling and will then be offered prenatal genetic tests. A limited number of diseases can be detected in this way, including sickle-cell disease, muscular dystrophy, Tay-Sachs disease, mitochondrial disease and cystic fibrosis. Prenatal genetic testing is also used to detect chromosome disorders such as Down’s syndrome.

Tests for several other conditions are in development. Some people argue that we should do all we can to rid society of any debilitating condition. Others think that tests for an increasing number of disorders would discriminate against ‘differently abled’ people, producing a society that’s intolerant of difference.

The headlines show how two papers tell the story in very different ways: the first more positive, the second less so. With these in mind, think about your own views and answer the questions that follow.

Q: Who do you think should be offered prenatal genetic testing? For what kinds of conditions?

Preimplantation genetic diagnosis

Alternative headlines: Baby to be born free of breast cancer after embryo screening; Genetic embryo screening: where will it end?
CC BY

‘Big Picture: Genes, Genomes and Health’ (2010)

This is a particular kind of prenatal testing. Embryos are created by IVF, then one cell is taken from each embryo and tested for the presence of a particular genetic mutation before an embryo is selected for implantation. This procedure can help people who carry disease-causing mutations that could affect their children. Preimplantation genetic diagnosis can be used to test for more than 100 conditions.

The list of mutations that can be identified using preimplantation genetic diagnosis includes the BRCA1 and BRCA2 mutations that indicate an increased risk of breast cancer. Women with a family history of breast cancer have used the technique to conceive babies free of the mutations.

The headlines show how two papers tell the story in very different ways: the first more positive, the second less so. With these in mind, think about your own views and answer the question that follows.

Q: Do you think that parents should be allowed to use preimplantation genetic diagnosis to screen embryos in this way?

Preimplantation tissue typing

Alternative headlines: My little brother was born to save my life; Concern over spare part babies
CC BY

‘Big Picture: Genes, Genomes and Health’ (2010)

This allows parents to select an embryo that could become a ‘saviour sibling’, a brother or sister who can donate ‘matched’ stem cells to a sick sibling affected by an illness such as leukaemia. Here, parents select an embryo for implantation that has the same tissue type (i.e. that is matched for human leukocyte antigen) as the sick child.

The Human Fertilisation and Embryology Authority (HFEA) licenses preimplantation tissue typing (to produce ‘saviour siblings’) on a case-by-case basis in the UK. The first such licence was granted in 2002.

The headlines show how two papers tell the story in very different ways: the first more positive, the second less so. With these in mind, think about your own views and answer the question that follows.

Q: Do you think it’s fair to select an embryo in this way to save a sibling?

What regulation is there?

Prenatal diagnosis has no special legislation apart from that covering termination of pregnancy (abortion). The decision about whether to have a test during pregnancy is made between the woman, her family and the doctors looking after her.

Genetic tests during pregnancy are available on the NHS if there is a family history of a condition or if they are offered as part of a population screening programme. The UK National Screening Committee decides which conditions are screened for. Although some additional tests may be available through private clinics, there is no test to screen all of the genes in a fetus or embryo.

The HFEA oversees all IVF procedures and research on embryos in the UK.

Sex selection is only allowed for medical reasons, for instance to avoid having a child affected by an X-linked disorder such as Duchenne muscular dystrophy. Such diseases, in which mutated genes are carried on the X chromosome, more often affect males (who have one X chromosome) than females (who have two).

Q: Who should decide what prenatal genetic tests and screening are carried out?

Lead image:

A fertilised mouse oocyte having human DNA microinjected into one of its pronuclei.

M Osmond/Wellcome Images

Further reading

About this resource

This resource was first published in ‘Genes, Genomes and Health’ in January 2010 and reviewed and updated in December 2014.

Topics:
Genetics and genomics, Medicine, Health, infection and disease
Issue:
Genes, Genomes and Health
Education levels:
16–19, Continuing professional development