3 Parents, 1 Child?!

3 parent

Imagine having a father, a biological mother, ANDDD another genetically related mother. Sounds crazy, but could soon be a possibility.

There has been much talk in the media recently about the new in vitro fertilization method. A ground breaking new method that will eliminate any mutations within mitochondrial DNA that can be passed from mother to child, but at the same time, creating a child from the DNA of 3 adults. After much reading of the many articles on the web, this is my quick summary of what 3 parent IVF involves!

Mitochondrial DNA?

Some diseases such as mitochondrial myopathies (muscle affecting conditions) can be caused by mutations within the mitochondrial DNA, separate to the DNA powerhouse that is the nucleus. It is the nucleus that contains 46 chromosomes, half from the mother and half from the father but it is in the cytoplasm of all but the red blood cell that mitochondria are found. These cells work hard to create energy for the cell to use in various processes, and is also where around 1% of the DNA found in a person is located. The DNA is in a circular form, and contains 37 genes.

And how is it done?

There are two methods that both result in the DNA of the child being passed down from 3 parents, and eliminates any chance of mitochondrial diseases being present in the child. Both methods involve the use of a donor, to get mitochondrial DNA without defects that may cause disease.  Every year, around 1 in 200 children are born with a mitochondrial disease.

The first  method involves creating an embryo with the intended parents sperm and egg, and the pronuclei of this removed and planted into a donor embryo, and is known as a pro-nuclear transfer.  [4]Mitochondrialdisease-creditAusSMC

Image from [4]

The other is  known as a maternal spindle transfer [1].  The chromosomes from an unfertilized egg containing defects within the mitochondrial DNA are taken and transplanted into an empty egg from a donor, and then fertilization is allowed to take place. Experiments using these methods have shown to be successful with eggs able to undergo fertilization in a lab [3].0,,16253959_401,00

Image from [3]

Will everyone be happy about this?

These new methods will help progress science in previously unimaginable ways.  However, regulation of these needs to be strictly observed.  The Human Fertilisation and Embryology Authority (HFEA) in 2008 made an amendment to the HFE 1990 Act, allowing, “regulations to be passed that will allow techniques, which alter the mitochondrial DNA of an egg or embryo, to be used in assisted conception to prevent the transmission of serious mitochondiral disease.” [2] This allows the research into replacement to go ahead but not treatment as of yet, but others have doubts as to whether it should be allowed at all.  Pro-life groups are against the creation and destruction of embryos, and wish for IVF and research on embryos to be abolished.

Others are asking if this is even needed when there are alternative solutions.  Egg donation and PGD (preimplantation genetic diagnosis) [5] are already in use and the consequences of their use known, whereas these new techniques are not totally known, and donor eggs are already high in demand.

I personally believe this is a great idea, enabling infertile couples to have more options into their quest for parenthood.  What do you reckon?

References/extra reading

[1] http://www.dw.de/three-way-ivf-faces-public-consultation/a-1625448

[2] http://www.nhs.uk/news/2012/09September/Pages/Consultation-launched-on-three-parent-IVF.aspx)

[3] http://www.nhs.uk/news/2012/10October/Pages/Three-parent-IVF-creates-viable-human-embryos.aspx

[4] http://www.sciencemediacentre.co.nz/infographics/

[5] Poulton and Oakeshott (2012) Nuclear transfer to prevent maternal transmission of mitochondrial DNA disease, BM,J 345:e6651

Sex Selection- What is it and should it be allowed?

Sex selection for personal reasons is illegal in the UK.  Full stop.  In fact, unless there is a serious medical reason in which would seriously affect the health of the child, it is illegal to choose your future child’s gender.  Is this right? Should couples with 3 boys wanting another child, but this time a girl be allowed to choose the sex of their baby? Or should it be left to mother nature and her mysterious ways? So many questions…

Why?

In some countries, such as India, finding out the sex through ultrasound before birth is illegal, due to the high occurrence of sex-selective abortions, deliberately aborting a foetus as it is of the ‘wrong’ sex, with preference usually shown to males, given that they are able to follow on the family name and allowed to get the family inheritance.  India is an extreme example, take for instance the recent horrific and deadly attack on a 23 year old girl, this shocking article shows the extreme lengths that gender has an effect on people’s lives.

In the past decade many couples have decided to go abroad to become pregnant, spending thousands of pounds to ensure they get their desired child, and sometimes illegally.  American law is less restrictive on these matters and so many have flown across to access this legal sex-selection process [1].human-sex-chromosomes

How can it be done?

  • In vitro fertilisation/ Pre-implantation genetic diagnosis (IVF/PGD)

Take a look at this short video that goes over the basics of PGD:

This is the only really trusted selection method allowed in the UK and is purely to prevent a child being born with a serious medical condition.  Some diseases are genetic, and can be sex-linked, meaning only one sex is affected, though often the other gender can be a carrier.  This is shown in the X-linked recessive disease, Duchenne muscular dystrophy in which only boys are affected, resulting in muscle degeneration, leading onto death at an early age.  A female can survive but be a carrier of the disease, whilst all boys will be affected.

The method requires IVF to be carried out but has an almost 100% chance of getting the desired baby gender.  Before the fertilised egg is transferred into the woman for implantation, the cells are analysed to find out the sex of the embryo.   As described in the video, a needle is inserted into the 3-5 day old blastocyst and a cell taken for analysis.  Only female embryos are taken forward to be implanted, eliminating any risk of the woman carrying a male child with the Duchenne muscular dystrophy.  There is no risk of harming the embryo by carrying out pre-implantation analysis on it.

Pre-implantation diagnosis can be used to select for embryos are of the desired gender, and only these embryos used in the IVF process that follows [2]. This method identifies embryos that contain either only X sex chromosomes (for a girl) or X and Y chromosomes (for a boy) but can also be used to screen for genetic conditions or to identify embryos that are at risk from genetic diseases.  This knowledge can then be used to choose genetically healthy embryos, preventing diseased children in couples that are known to be suffering or carriers of genetically inherited diseases such as cystic fibrosis or Huntington’s disease.  These diseases are caused by a single gene mutation, enabling scientists to easily identify affected embryos.

Pink or blue clothes?babay clothes

Other options, such as a maternal blood sample or an ultrasound scan can be used to carry out prenatal sex testing of the foetus before birth, but these require a growing embryo within the uterus, and so are useful for preparing for the child’s arrival, but no good for the prevention of sex-linked diseases, or for couples wanting to ‘balance’ their families.

So what have we learnt?  Different countries have different beliefs and laws about sex selection, whether for the prevention of children with genetic diseases, or just due to the parent’s desire.  The only reliable way to check pre-implantation is by PGD.

Would PGD prevent the horrific attacks on women in India, or is this completely irrelevant and is society that needs to change, and not the way we chose our child’s gender, and that any child is a blessing? In what situation is PGD acceptable…?

References/extra reading

[1] British couples flying to US for banned baby sex selection, The Telegraph, available at: http://www.telegraph.co.uk/health/healthnews/9504503/British-couples-flying-to-US-for-banned-baby-sex-selection.html

[2] Sex (Gender) Selection, available at: http://www.lajollaivf.com/fertility-treatments/sex-gender-selection-san-diego/

Multiple pregnancy IVF

This news article came out yesterday in The Guardian online, reporting on the use of multiple embryos being transferred into the uterus during IVF.  The article focuses on a study carried out by scientists at the Leicester Infertility Centre.  

A pretty interesting read, and gives the view that using a single embryo in the IVF process has just the same chance as multiple embryos for a healthy live birth, without the risks associated with multiple births, such as high blood pressure and pre-eclampsia.  There is also a much higher risk of twins or triplets being born prematurely, leading to a risky start in life with the possibility health problems after birth and later on in life.

The article says how single embryo transfer should implemented in the UK, reducing multiple birth pregnancies, preventing health risks to the mother and child.

Are Men Needed Anymore?

Came across this the other day- http://www.bbc.co.uk/news/world-us-canada-19879113

Pretty interesting news article.  What would be the consequences of this?  Imagine a world where you can become the father or mother of a child even if your sperm or eggs would not allow you to do so naturally by taking another of your cells and turning into a cell carrying the right DNA to create a child?

sperm around egg

Amazing technology that could give infertile couples another option in the aim for a child.  However, although the research has worked on mice, there is a long way to go until this technique could even be thought of to be used in IVF on a daily basis, the scientists involved have set themselves a target of 2 years to create usable sperm and 5 years for eggs.  I wish them all the very best of luck!

What are your thoughts on this?