MAP project

2. WORLD’S FIRST BABY BORN WITH NEW « 3 PARENT » TECHNIQUE
In 2005, a couple gave birth to a baby girl. It was then that they discovered the probable cause of their fertility
problems : a genetic mutation in the mother's mitochondria. Their daughter died at the age of six.The couple's
second child had the same disorder, and lived for 8 months.
A five-month-old boy is the first baby to be born by using a new technique that incorporates DNA from three
people. He is showing no signs of the disease of their parents.
The controversial technique, which allows parents with rare genetic mutations to have healthy babies,
has only been legally approved in the UK. But the birth of the child, whose Jordanian parents were treated by a
US-based team in Mexico, should fast forward progress around the world.
The boy's mother carries genes for Leigh syndrome, a fatal disorder that affects the developing
nervous system. Genes for the disease lay in the DNA in the mitochondria which provide energy for our cells and
carry 37 genes that are passed down to us from our mothers. This is separate from the majority of our DNA,
which is located in each cell's nucleus.
Around a quarter of her mitochondria have the disease-causing mutation. While the mother was
healthy, Leigh syndrome was responsible for the deaths of her two children.
Doctor Zhang has been working on the way to avoid mitochondrial disease using the so-called
«three parent» technique. In theory, there are a few ways of doing this. The method approved in the UK is called
pronuclear transfer and involves fertilising both the mother's egg and a donor egg with the father's sperm. Before
the fertilised eggs start dividing into early-stage embryos, each nucleus is removed. The nucleus from the donor's
fertilised egg is discarded and replaced by that from the mother's fertilised egg.
But because of the parents' religion, they are Muslims, they were opposed to the destruction of two
embryos. So the Doctor took a different approach, called « spindle nuclear transfer ». He removed the nucleus
from one of the mother's eggs and inserted it into a donor egg that had had its own nucleus removed. The
resulting egg – with the nuclear DNA from the mother and the mitochondrial DNA from a donor – was then
fertilised with the father's sperm.
Lycee et college Victor Duruy Team

4. After the successful procedure of the three-parent baby in Mexico, the same
procedure was applied in Ukraine. The child was born on January 5th. A team
led by fertility researcher Valery Zukin at the Nadiya clinic in Kiev helped the
baby's parents to conceive by using an in vitro fertilisation (IVF) technique
called pronuclear transfer. Baby’s mother had been trying to conceive for years
and had been through four unsuccessful rounds of conventional IVF. Although
her eggs were fertilised successfully, they stopped growing before they could be
implanted in her womb. The condition is known as an embryonic arrest. Dr.
Zukin’s team made a hybrid embryo. Mother’s egg was fertilised with her
partner’s sperm and then the resulting pronucleus was transferred into an egg
from a donor female. The embryo was then implanted into the mother’s womb.
The result was a baby with the genetic identity of both parents, along with the
mitochondrial DNA from the donor.
The genetic test performed on the baby shows that the child is completely
normal. These days in Zukin’s clinic are expecting another three-parent baby to
be born to a mother infertile for seven years.
School of Midwifery Team