23:56 4th February 2017 | IVF & Mitochondria

Mitochondrial Replacement Therapy MRT Pronuclear Transfer Technique Maternal Spindle Transfer Mitochrondrial Disease Dysfunctional Mitochindria Mutations mtDNA nDNA RNA Molecules HFEA Genetic Disease Mitochondrial Replacement Theraphy Unexplained Infertility Genetic Modification

Three-parent IVF – officially known as Mitochondrial Replacement Therapy (MRT) – continues to raise concern in some circles while gaining traction in others.

MRT, through pronuclear transfer technique (more common in UK) or maternal spindle transfer, was pioneered to prevent the transmission of mitochondrial disease, a group of disorders caused by dysfunctional mitochondria, from one generation to the next

The Cause of Mitochondrial Diseases

Mitochondrial diseases result from mitochondria failures. Either inherited mutations or spontaneous mutations in mtDNA or nDNA, which alter the functions of the proteins or RNA molecules present, can cause mitochondrial diseases.

What Mitochondrial Replacement Therapy Entails

Essentially, defective ovum mitochondria is replaced with healthy mitochondria from a donor to help prevent passing a mitochondrial disease to a child, consequently resulting in three-parent babies.

Who has Used this Technique?

Although this innovative fertility technique was already legalised in the UK in February 2015, with the sole purpose to assist women with mitochondrial disease, the Human Fertilisation and Embryology Authority (HFEA) advised that more research was required for safety and efficiency purposes. However, on 30 November 2016, the HFEA decided that the therapy should be approved for “cautious clinical use” and 15 days later, the conclusion was endorsed by the HFEA in cases where there are risk of inheriting genetic diseases. As a result, doctors could have already started using the treatment and the first babies could be born before 2018.

The technique was pioneered by Newcastle University and several women already want the procedure. Prof Sir Doug Turnbull, Director of the Welcome Centre for Mitochondrial Research at Newcastle University, aims to treat up to 25 carefully selected patients a year with the mitochondrial donation technique (long-term follow-up of children born included).

To date, MRT research in the US has been limited and there has been no governmental approval of the technique.

In Mexico, there are no laws preventing Mitochondrial Replacement Therapy (MRT) and in April 2016 the first baby was born as a result of using the technique through maternal spindle transfer.

MRT was also used in Kiev, Ukraine, to help a couple with fertility issues. However, in this controversial (although not forbidden) case, a girl was conceived and delivered to a mother suffering from unexplained infertility as opposed to mitochondrial disease.

Although several precautions were taken in the Ukraine case, the procedure caused great concern as genetic modifications produced in girl babies can be passed onto potential future children. Boy babies carrying donor mitochondria cannot pass their modified genetics onto any potential future children. Once an embryo is formed, the masculine mitochondrion dies, i.e. only mitochondria from the mother's egg remain.

Reasons for Concern

Despite the technique enabling selective reproduction for health and safety reasons, some feel that it can, and will be, misused.

A significant argument against MRT revolves around opening the door to so-called designer babies, essentially allowing parents to select traits for their children. Many are concerned about the potential for abuse in the name of eugenics and how it relates to abortion.

There is also the fact that a child born of MRT technically has three genetic parents. The mother with the nuclear DNA; the donor mother who provided the mtDNA; and the father who provided the sperm.

Could there also be issues of identity and parental obligation in the near future?

Only time will tell.

Sources

Telegraph.co.uk                umdf.org                        Accessscience.com

academic.oup.com            ibtimes.co.u                  Thelilyfoundation.org.uk   www.umdf.org

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