Transcript 1b PPT – Foetal Growth and Genetics

http://www.youtube.com/watch?v=mdGsLRGBsCU&NR=1&featu
re=fvwp
http://www.youtube.com/watch?v=duPxBXN4qMg&NR=1&f
eature=fvwp
http://www.youtube.com/watch?v=UgT5rUQ9EmQ
1. Fertilization begins when the sperm penetrates the egg and ends with the
production of a zygote. This normally takes 24 hours. This is significant as it is
the very first stage of embryonic and fetal development.
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Using the pattern parts of the egg and sperm – and the drawings on the board put together an
information diagram that you feel could help you revise from for your examination. Label each part
and explain what is happening during each process.
4. Cardiac Muscle Contraction Begins
Neural Folds/Heart Folds begin to fuse. This
happens within 21-23 days from fertilization.
The two endocardial tubes formed
previously now fuse. Together they form one
single tube generated from the cells of the
“roof” of the nueral tube. The heart tube
takes on an S-shape establishing the
asymetry of the heart. As the S-shape forms,
cardiac muscle contraction begins.
5. Kidneys Start to Produce Urine- this
happens around 44-48 days. Kidneys
remove toxins and waste from the body and
are essential to survival.
6. Brain Structure Complete – at 61-68 days.
This is necessary to control thinking,
breathing, movement, etc.
7. Fetus is Able to Hear- 22 weeks.
8. Lung Development- at 26 weeks the lungs
are developed enough to breath oxygen.
9. Use of Eyes- at 32 weeks the
baby can open and close its
eyes.
10. Birth- the baby is fully
developed and ready to be
born at 40 weeks.
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Once the baby is born it
will be made up of all
millions of pieces of
genetic information past
on from its parents. This
means everything from the
colour of the eyes, hair,
shape of hands, nails,
height the baby will grow
to and any other inherited
weaknesses – such as illness
– also emotions,
intelligence and so on.
Have people ever said to
you, "It's in your genes?"
They were probably
talking about a physical
characteristic,
personality trait, or talent
that you share with other
members of your family.
We know that genes play
an important role in
shaping how we look
and act and even
whether we get sick.
Now scientists are trying
to use that knowledge in
exciting new ways, such
as preventing and
treating health problems.
9. Use of Eyes- at 32 weeks the
baby can open and close its
eyes.
10. Birth- the baby is fully
developed and ready to be
born at 40 weeks.
Although most DNA is packaged in
chromosomes within the nucleus,
mitochondria also have a small
amount of their own DNA.
Mitochondria are structures
within cells that convert the
energy from food into a form
that cells can use. 37 genes
contain the DNA to help break
down food
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To understand how genes
(pronounced: jeens) work,
let's review some biology
basics. Most living
organisms are made up of
cells that contain a
substance called
deoxyribonucleic
(pronounced: dee-ahksee-rye-bow-noo-klee-ik)
acid (DNA).
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DNA is wrapped together
to form structures called
chromosomes
(pronounced: krow-muhsoams).
Most cells in the human
body have 23 pairs of
chromosomes, making a
total of 46. Individual sperm
and egg cells, however,
have just 23 unpaired
chromosomes. You
received half of your
chromosomes from your
mother's egg and the other
half from your father's
sperm cell. A male child
receives an X chromosome
from his mother and a Y
chromosome from his
father; females get an X
chromosome from each
parent.
Female
Male
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Thousands of genes are packed together to form
chromosomes. Most people have 46 chromosomes (23
pairs). There are 44 “non-sex” chromosomes, numbered in
pairs from 1-22, that are the same in males and females.
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We call the 23rd pair the “sex” chromosomes because
they determine a person’s sex (male or female). In
females, both sex chromosomes are similar and are called
“X” chromosomes. Males have one “X” and one “Y”
chromosome.
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Chromosomes are the
packaging for our
genetic material, or
DNA
(deoxyribonucleic
acid). DNA carries a
specific code that
gives instructions to
our body on how to
grow, develop and
function. The
instructions are
organized into units
called genes.
Some characteristics come from a
single gene, whereas others come from
gene combinations. Because every
person has from 25,000 to 35,000
different genes, there is an almost
endless number of possible
combinations!
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We start this reduction process
with a double set of chromosomes
(one from dad and one set from
mum) and reduce it down to one
set.
The double set consists of 23 pairs
of homologous chromosomes, or
homologues, one of each pair
from one parent, the other from
the other parent.
The genes are arranged along
both homologues in the same
order but carry different types of
information---blue vs brown eyes
and so on.
In the context of chromosomes,
"gene" is not used but instead
"locus" and "allele" are the correct
terms.
So what makes up the gene? Each
allele is a packet of information made
of sugars, phosphates, nitrogen bases
and hydrogen bonds!
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Now imagine that a shoelace also has
another plastic bit in the middle, and
through this you can connect a pair of
shoelaces together for storage. This is
called a centromere on a
chromosome, and it is where the
chromosome pairs connect.
Imagine a
chromosome as being
a shoelace. The plastic
bits at the end of the
shoelace keep the
material which makes
up the shoelace from
unravelling.
Chromosomes have
similar 'plastic bits' at
each end called
telomeres. They
protect the ends of the
chromosome from
degradation.
Task 1
1.
2.
Draw up a pair of
homologues that
could relate to the
DNA of your mother
or father.
Now think about
you – what DNA
homologue
information have
you inherited from
your mother and
father.
1.
Now draw a
diagram of the
homologue with the
information you
think has been
linked (allele or
locus)
Now looking at the gene pool –
begin to compile diagrams –
again to help you memorise and
revise from.
 What are Chromosomes?
1.
How many from the female egg
and male sperm make up a
zygote?
2.
What is DNA?
3.
Looking at the pictures you have
brought from home, look at the
similarities between your siblings,
mother and father and aunts
and uncles and grandparents.
4.
List these similarities
5.
Now draw a diagram of two X
chromosomes and the short
strand P and long Strand Q
chromosome information explain how your parents
genetic information has resulted
in your identified similarities.
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Discuss as a group
what DNA (genetic)
information has been
past onto you.
Genes play an important role in
shaping what we are today and for all
our so-called genetic traits. The genetic
information of parents is passed down
to their children, grand children, or
even great grand children. Similarly we
have also inherited a number of
genetic traits from our ancestors.
All our physical characteristics,
personality traits, and talents can be
the result of the genetic make up of our
ancestors.
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The chromosomes carry genes, which
are the segments of DNA that determine
factors and a whole range of
characteristics. The color of our hair, our
height, and even our predisposition to
health concerns are some of the genetic
traits that we have inherited from out
parents.
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Genetic information is contained in
the genes of a person and as the
cells of the body duplicate, the
genetic information is passed to the
new cells.
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In our genetic make up, certain
genes are dominant and influence
the genetic trait of a person even if
only one copy of that dominant
gene is present in that pair of
chromosomes. On the other hand,
certain genes are recessive and do
not affect the genetic trait of a
person even if they are present on
both chromosome pairs.
For example,
spina bifida (a
neural tube
 Our genetic make-up is also
defect) in
responsible for a number of
health problems that we face. newborns can
Some examples of genetic, or be avoided if
their mothers
inherited, health problems
include obesity, heart
take folic acid
disease, cancer, diabetes,
during early
and hypertension.
pregnancy and
 Many health concerns come continue taking
about due to a combination
it until their
of our inherited genetic
doctor advises
make- up and environmental them to stop.
triggers, such as unbalanced
diet, chemical exposure, and
unhealthy lifestyle.
Cri-du-chat (cat's cry) syndrome, also known as 5p- (5p
minus) syndrome, is a chromosomal condition that results
when a piece of chromosome 5 is missing. Infants with this
condition often have a high-pitched cry that sounds like
that of a cat. The disorder is characterized by intellectual
disability and delayed development, small head size
(microcephaly), low birth weight, and weak muscle tone
(hypotonia) in infancy. Affected individuals also have
distinctive facial features, including widely set eyes
(hypertelorism), low-set ears, a small jaw, and a rounded
face. Some children with cri-du-chat syndrome are born
with a heart defect.
 How common is cri-du-chat syndrome?
 Cri-du-chat syndrome occurs in an estimated 1 in 20,000 to
50,000 newborns. This condition is found in people of all
ethnic backgrounds.
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Cri-du-chat syndrome is caused by a deletion of the end
of the short (p) arm of chromosome 5. This chromosomal
change is written as 5p-. The size of the deletion varies
among affected individuals; studies suggest that larger
deletions tend to result in more severe intellectual disability
and developmental delay than smaller deletions.
 The signs and symptoms of cri-du-chat syndrome are
probably related to the loss of multiple genes on the short
arm of chromosome 5. Researchers believe that the loss of
a specific gene, CTNND2, is associated with severe
intellectual disability in some people with this condition.
They are working to determine how the loss of other genes
in this region contributes to the characteristic features of
cri-du-chat syndrome.
 Read more about the CTNND2 gene and chromosome 5.
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Most cases of cri-du-chat syndrome are not
inherited. The deletion occurs most often as a
random event during the formation of
reproductive cells (eggs or sperm) or in early
fetal development. Affected people typically
have no history of the disorder in their family.
About 10 percent of people with cri-du-chat
syndrome inherit the chromosome
abnormality from an unaffected parent. In
these cases, the parent carries a
chromosomal rearrangement called a
balanced translocation, in which no genetic
material is gained or lost. Balanced
translocations usually do not cause any
health problems; however, they can become
unbalanced as they are passed to the next
generation. Children who inherit an
unbalanced translocation can have a
chromosomal rearrangement with extra or
missing genetic material. Individuals with cridu-chat syndrome who inherit an unbalanced
translocation are missing genetic material
from the short arm of chromosome 5, which
results in the intellectual disability and health
problems characteristic of this disorder.
What are the symptoms of Cri-du-Chat
syndrome?
Babies with cri-du-chat are usually small at birth, and may have respiratory problems. Often, the
larynx doesn't develop correctly, which causes the signature cat-like cry.
People who have cri-du-chat have very distinctive features. They may have a small head
(microcephaly), an unusually round face, a small chin, widely set eyes, folds of skin over their eyes,
and a small bridge of the nose.
Several problems occur inside the body, as well. A small number of children have heart defects,
muscular or skeletal problems, hearing or sight problems, or poor muscle tone. As they grow, people
with cri-du-chat usually have difficulty walking and talking correctly. They may have behavior
problems (such as hyperactivity or aggression), and severe mental retardation. If no major organ
defects or other critical medical conditions exist, life expectancy is normal.
Although there is no real treatment for
cri-du-chat syndrome, children with the
disorder can go through therapy to
improve their language skills, motor skills,
and to help them develop as normally as
possible.
 In 80 percent of the cases, the
chromosome carrying the deletion
comes from the father's sperm rather
than the mother's egg.
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Down
syndrome is a
genetic
condition in
which a
person has 47
chromosomes
instead of the
usual 46.
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In most cases,
Down syndrome
occurs when there
is an extra copy of
chromosome 21.
This form of Down
syndrome is called
Trisomy 21. The
extra chromosome
causes problems
with the way the
body and brain
develop.
Down's syndrome is caused by having
an extra copy of chromosome 21
Common physical signs
include:
Decreased muscle tone at birth
Excess skin at the nape of the
neck
Flattened nose
Separated joints between the
bones of the skull (sutures)
Single crease in the palm of the
hand
Small ears
Small mouth
Upward slanting eyes
Wide, short hands with short
fingers
White spots on the colored part
of the eye (Brushfield spots)
Long-term (chronic)
constipation problems
Sleep apnea (because the
mouth, throat, and airway are
narrowed in children with Down
syndrome)
Teeth that appear later than
normal and in a location that
may cause problems with
chewing
Underactive thyroid
(hypothyroidism)
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Physical development is often slower than normal. Most children with Down syndrome
never reach their average adult height.
Children may also have delayed mental and social development. Common problems
may include:
Impulsive behavior
Poor judgment
Short attention span
Slow learning
As children with Down syndrome grow and become aware of their limitations, they may
also feel frustration and anger.
Many different medical conditions are seen in people with Down syndrome, including:
Birth defects involving the heart, such as an atrial septal defect or ventricular septal
defect
Dementia may be seen
Eye problems, such as cataracts (most children with Down syndrome need glasses)
Early and massive vomiting, which may be a sign of a gastrointestinal blockage, such as
esophageal atresia and duodenal atresia
Hearing problems, probably caused by regular ear infections
Hip problems and risk of dislocation
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Williams Syndrome is a
rare genetic condition,
found in one in about
7500 newborns. These
children are hypersocial, with
personalities you hardly
see outside the world
of this syndrome. They
demonstrate extreme
empathy and show
warmth and openness
even to strangers.
These children or adults are extremely
empathetic in nature. They can’t see
anyone in pain, and if such a situation
arises they are the first ones to extend
help. An experiment was carried out in
which a girl hit her knee on the table. A
typical child just watched her cry, while
the child having Williams Syndrome
showed more concern. He went to her
and rubbed her knee. He even asked
“What happened?”.
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With such empathy
comes lack of fear. These
children are not aware of
somebody’s ill intensions
to harm them, neither are
they scared of dangerous
situations or objects. If
they are given a spider,
they’ll most likely pet it,
rather than being scared.
Such extreme innocence
can have real life
consequences, and for
the same reason, such
people are always in
need of protection, since
they are incapable of
detecting danger or
defending themselves on
their own.
Studies show that the Syndrome is
caused by the absence of around 26
genes on chromosome 7, and it can
have extreme effects on physical,
behavioural or cognitive composition
of a person. This deletion of
chromosomes takes place during the
production of a sperm or egg cell.
However, the reason as to why the
absences of these genes result in hyper
social behavior remains a mystery.
Most adults and children with Williams
syndrome lead full, active and healthy
lives, but it's important to be aware of
the possible problems that may arise
and to address them as soon as
possible. For this reason, an expert
team is needed that includes doctors
and nurses, as well as the skills of
occupational speech therapists,
physiotherapists and teachers.
http://geneticsf.labanca.net/
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Turner’s Syndrome is a medical disorder that
can only occur in girls because they only
have two X chromosomes. The disease
consists of one X chromosome’s parts missing
or not there altogether. Boys with this disorder
do not finish developing because they have
an X and Y chromosome. Without the X
chromosome, no one could live off of a Y
chromosome. This disorder was founded by
Dr. Henry H. Turner (an endocrinologist) in
1938.
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One in every 2,500 births will be diagnosed
with Turner’s Syndrome. Some of the physical
symptoms of this disorder are a short stature,
lack of menstruation and breast
development, infertility, a “webbed”neck,
abnormal bone growth (especially in the
hands and elbows), and edema (extra fluid)
in the hands and feet as infants. Girls with this
disorder may also have a low-self esteem due
to their different appearance, difficulties with
math, and skills like visual organisation and
map-reading.
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There is no specific cure for this disorder. If
diagnosed as a growing child, growth
hormones could be given. When the girl
reaches 12 or 13 years old, estrogen levels
can be given as well. This disorder has an
unknown cause, therefore, there is no
prevention.GKDE
http://ghr.nlm.nih.gov/chromosome/7
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Another sex-linked genetic
condition is Duchenne’s
muscular dystrophy, which
cause progressive
deterioration in muscle
fibres. It affects about one
in 3,000 boys and there is
no effective cure. A blood
test looks for the enzymes
released from damaged
muscles.
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Large numbers of disorders
are caused by additive
effects of certain genes
together with various
environmental factors, but
the actual pattern of
inheritance is complex:
these care called
multifactorial disorders.
Asthma, insulin-dependent
(Type 1) diabetes mellitus,
schizophrenia and some
congenital birth defects
such as cleft palate are
classed as multifactorial
disorders.
Genetics Home Reference
includes these genes on
chromosome 7:
•AASS
•ABCB4
•ASL
•BRAF
•C7orf11
•CCM2
•CFTR
•CLCN1
•CLIP2
•COL1A2
•DDC
•DFNA5
•DLD
•ELN
•FAM126A
•GARS
•GARS
•GLI3
•GTF2I
•GTF2IRD1
•GUSB
•HOXA13
•HSPB1
•KCNH2
•KRIT1
•LFNG
•LIMK1
•NCF1
•OPN1SW
•PEX1
•PMS2
•POR
•PRKAG2
•SBDS
•SGCE
•SHH
•SLC25A13
•SLC26A4
•TFR2
•TWIST1
What is chromosome 7?
Humans normally have 46
chromosomes in each cell,
divided into 23 pairs. Two
copies of chromosome 7, one
copy inherited from each
parent, form one of the pairs.
Chromosome 7 spans about
159 million DNA building
blocks (base pairs) and
represents more than 5
percent of the total DNA in
cells.
Identifying genes on each
chromosome is an active
area of genetic research.
Because researchers use
different approaches to
predict the number of genes
on each chromosome, the
estimated number of genes
varies. Chromosome 7 likely
contains about 1,150 genes.
These genes perform a variety
of different roles in the body.
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You are requested to find out about a
syndrome we have not discussed in
lesson.
http://geneticsf.labanca.net/
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Put together a display about the
syndrome you have researched and
what chromosomes and then genes are
missing or appear to be extra. Present to
the group
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In each human cell, except the egg and sperm cells, there are 46 chromosomes, made
up of 23 pairs (see Genetics Fact Sheet 1). There are
22 pairs of autosomes that scientists have numbered 1-22 according to their size from
the largest to the smallest
Two sex chromosomes: X and Y
When egg and sperm cells are formed, the chromosome pairs separate so that there is
only one of each pair in these cells ie. 23 chromosomes instead of 46.
A baby is conceived when the egg from the mother and the sperm from the father
come together. The baby would then have two copies of each chromosome (46
chromosomes in total) just like the parents.
One copy of each chromosome would have come from the mother and one copy
from the father.
Sometimes, when the egg and sperm are forming, a mistake occurs so that the
chromosome pairs do not separate in an ordered fashion.
The result is an egg or sperm cell that has only 22 chromosomes while others have 24
chromosomes
If an egg or sperm carrying 22 chromosomes combines with an egg or sperm carrying
the usual 23 chromosomes, the result would be an individual with cells in which there are
45 chromosomes instead of the usual.
Missing (deleted) portions of the short
('p'), or the long ('q') arm of the X
chromosome One of the X chromosomes
arranged in a ring form The two long ('q')
arms of the X chromosomes joined
together in an arrangement called
isochromosome Xq
 Very rarely, cells that contain part of the
Y chromosome may be present
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Males and females can inherit up to 3 extra sex
chromosomes possibly bringing their total
count up to even 49 chromosomes.
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In the case of Tetra X syndrome, females have
four X chromosomes instead of two. Therefore,
they have 48 chromosomes (48, XXXX) instead
of 46. In the case of Penta X syndrome, there
are five X chromosomes or a total of 49
chromosomes (49, xxxxx). Tetra/Pentasomy X
occurs only in females. There are
approximately 60 known females worldwide
with this rare condition, although it is believed
that there are probably many more who are
undiagnosed. The condition was first identified
in 1961.
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Examination style questions – please
carry these out and hand in this lesson
next week
What is the life expectancy of a child
with Krabbe disease?
What are the symptoms?
What are the signs at birth to indicate
that a child has Krabbe?
In Israel there are know to be a higher
percentage of Krabbe disease babies
born. This means that over time what?
Explain where the genetic information
linked to Krabbe disease is found.
Explain how mothers/parents could
prevent a child being born with Krabbe
disease?
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Edexcel – Paper
What is Krabbe disease?
Krabbe disease (also called globoid cell
leukodystrophy) is a degenerative disorder that affects
the nervous system. It is caused by the shortage
(deficiency) of an enzyme called
galactosylceramidase. This enzyme deficiency impairs
the growth and maintenance of myelin, the protective
covering around certain nerve cells that ensures the
rapid transmission of nerve impulses. Krabbe disease is
part of a group of disorders known as leukodystrophies,
which result from the loss of myelin (demyelination). This
disorder is also characterized by the abnormal
presence of globoid cells, which are globe-shaped
cells that usually have more than one nucleus.
The symptoms of Krabbe disease usually begin before
the age of 1 year (the infantile form). Initial signs and
symptoms typically include irritability, muscle weakness,
feeding difficulties, episodes of fever without any sign
of infection, stiff posture, and slowed mental and
physical development. As the disease progresses,
muscles continue to weaken, affecting the infant's
ability to move, chew, swallow, and breathe. Affected
infants also experience vision loss and seizures.
Less commonly, onset of Krabbe disease can occur in
childhood, adolescence, or adulthood (late-onset
forms). Visual problems and walking difficulties are the
most common initial symptoms in this form of the
disorder, however, signs and symptoms vary
considerably among affected individuals.
How common is Krabbe disease?
In the United States, Krabbe disease affects about 1 in
100,000 individuals. A higher incidence (6 cases per
1,000 people) has been reported in a few isolated
communities in Israel.
Dominant Inheritance
One parent has a single, faulty
dominant gene (D), which overpowers
In our genetic make up, certain
its normal counterpart (d), affecting
genes are dominant and influence that parent. When the affected parent
the genetic trait of a person even if mates with an unaffected and nononly one copy of that dominant
carrier mate (dd), the offspring are
gene is present in that pair of
either affected or not affected, but
chromosomes. On the other hand, they are not carriers.
certain genes are recessive and
do not affect the genetic trait of a
person even if they are present on
both chromosome pairs.
Mechanisms of recessive and dominant
inheritance.
Recessive Inheritance
Both parents carry a normal gene (N),
and a faulty, recessive, gene (n). The
parents, although carriers, are unaffected
by the faulty gene. Their offspring are
affected, not affected, or carriers. This
type of inheritance was first shown by
Mendel.
http://www.accessexcellence.org/RC/VL/GG/index.php#Anchor-From-14210
For each trait you select, build a
Punnett square that could produce
your family's results. A sample is
shown below. Mother has green
eyes, father has brown eyes, child
has green eyes. In this case, the
brown gene is dominant over the
green gene. This could occur in
either of the combinations on the
right.
On a piece of paper, decide
which gene will be represented
by heads and which will be tails
for each coin you will be
flipping. It might be easier to use
different coins to represent
each parent.
Toss both coins 20 times for
each trait. Count the number of
times you get a result that
matches your own results (in our
example, the result we're
looking for is that the child has
green eyes) and divide that
number by 20. This is your
experimental probability.
Compare your experimental
probability with your theoretical
probability and present your
findings.
dominant
genes
recessive
genes
Key term
Define phenotype and genotype.
Phenotype – the appearance of an organism
Genotype – What causes the appearance of an organism
B = Brown eyes (dominant)
b = blue eyes (recessive)

Top green is Mum = B (From her mum) and B (From her dad) =
Brown eyes
Side greenis Dad =b (From his Mum) and b (From his Dad) = Blue
eyed
The child or offspring are therefore the boxes in yellow! All end up
with a dominant B gene so all children will be brown eyed!
Again:
B = Brown eyes (dominant)
b = blue eyes (recessive)
Mum in this case has one B (brown gene) and one b (blue gene) She
is still brown because brown is dominant!
Dad still has the two blue eyes genes!
The yellow off spring as you can see, 2 have the dominant B gene so
will be brown eyed and two have the recessive b gene so will be
blue eyed. It now is a 50/50 chance!
However if this were to happen!
Last one!
In this case both parents are brown eyed as they both
have the dominant brown eyed gene but they both carry
the recessive blue eyed gene! As you can see from the
grid, one offspring is totally dominant brown eyed BB (25%
chance) Two are dominant but carry the brown eyed
gene (50%) and only one had two blue genes! Only a 25%
chance you will have blue eyed children!
Now draw your Punnet square – think
about the colours of eyes your family
have, you can usually work out this
equation from the visual information
alone.
Once infertility or genetic disorders
have been diagnosed, a number of
options are available, depending on the
cause of the problem.
In vitro fertilisation (IVF)
What is it? Eggs and sperm are
collected and fertilised in the laboratory
before the resulting embryo is
transferred to the womb. The woman
takes fertility drugs to stimulate the
production of eggs. Once these are
mature, they're collected by the doctor,
using ultrasound to guide the collecting
tube. The man produces a sperm
sample, which is prepared before being
put with the eggs in a Petri dish and left
for a few days to see if fertilisation takes
place. If a healthy embryo develops,
this is placed in the womb using a
catheter (a very fine needle or probe).
Usually, no more than one or two are
placed. Any remaining embryos suitable
for freezing may be stored for future use.
The sperm and/or eggs used may be
the couple's own or donated.

IVF

What is it? PGD involves
checking the genes of
embryos aged between two
and five days, created by IVF
for genetic diseases such as
haemophilia and cystic
fibrosis, as well as for some
inherited diseases of later life
such as breast, ovarian and
bowel cancer. Disease-free
embryos may then be
transferred to the womb.
 When it's used: if a couple has
a child with a genetic disease
and is at risk of having
another; if there have been
several terminations because
a genetic disorder was
diagnosed; if there's a strong
family history of breast, bowel
or ovarian cancer.


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

Fertility drugs are often the first
treatment for women who aren't
ovulating. They work in the same way
as the body's own hormones, triggering
the ovaries to release eggs.
This method, known as ovulation
induction, can sometimes lead to
conception after a few months without
further intervention.
Possible side effects include
premenstrual symptoms such as
nausea, headaches and weight gain.
Such drugs are also used as part of
other more complicated treatments,
such as in vitro fertilisation and
intrauterine insemination (see below).
Other drugs - to help control the
menstrual cycle or thicken the lining of
the womb to prepare it for pregnancy,
for example - may also be used. These
can also cause side effects, such as
hot flushes, headaches, nausea and
swollen breasts.
Pre-implantation genetic
diagnosis (PGD)


17 January 2011

By Lucy Freem
Appeared in BioNews 591
Clinics should warn patients about the
increased risk of birth defects for
children conceived using fertility
treatment, say the Human Fertilisation
and Embryology Authority (HFEA).
The HFEA, the body which regulates all
UK fertility treatment centres, is
planning to release new guidelines.
They will ask clinics to
inform people seeking treatment about
the association between birth defects
and assisted reproductive technologies
(ART) such as IVF.
Health problems including low birth
weight and neurological conditions
such as cerebral palsy are more likely
to occur in children conceived through
fertility treatment, although the
increase is only slight.
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http://truthonmedecine.wordpress.co
m/2011/02/02/ivf-why-we-must-be-toldthe-truth-over-birth-defects/



risk of brain disorders in any resulting children. The
overall risk associated with fertility treatments is
small, however. Previous estimates from the HFEA
indicate that the risk of developing birth defects
increases from a general population level of
2 percent to 2.6 percent with fertility treatment.
After a comprehensive review, the HFEA is
updating its guidelines on patient information to
reflect current scientific research on the possible
side effects of ART.
According to the Sunday Times, the HFEA
believes that: ‘The birth defects issue is certainly
something that clinics should talk to their patients
about. At the moment there is not anything in
the code of practice [on the subject]. There is an
intention to tell patients about possible health
risks... so they can make informed choices about
their treatment’.
Individual procedures may carry specific
warnings under the new guidelines. For example,
couples who choose to have ICSI
(intracytoplasmic sperm injection) - a
procedure of particular use in the treatment of
male fertility problems - are already told that this
procedure may result in children with a higher
risk of infertility.
The HFEA now believes that clinics should also
warn patients who choose to have embryos
screened for disease-associated genetic
defects, because the screening process can
increase the
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

Chromosome defects in eggs were previously
considered to have resulted in the first stage
of cell division, which occurs when a woman
was herself a foetus in the womb. Finding
them during the second stage, which occurs
at ovulation, therefore suggests they may
have resulted from the hyperstimulation of the
ovaries during IVF treatment.
The defects included abnormal variations
from the usual number of 23 pairs of
chromosomes. Three copies of chromosome
21 instead of the normal two, for instance,
leads to babies with Down's syndrome. As
women get older it becomes increasingly
difficult for them to produce enough viable
eggs for IVF treatment. It is common practice
for older women to have their ovaries
stimulated with stronger doses of drugs than is
the case for younger women.
The results of the study are to be presented at
a fertility conference in Stockholm this week
but the scientists behind the research said
that they wanted to reassure older women
considering IVF treatment. They said further
work needs to be done fully to explain the
findings and there is no evidence to suggest
that IVF babies of older women are at any
higher risk of birth defects than babies
conceived naturally by women of the same
age.



"We found that some IVF eggs have up to
seven chromosome abnormalities. This
suggests the possibility that ovarian
stimulation during the treatment may have
caused some of these defects," said Professor
Alan Handyside, director of the London
Bridge Fertility, Gynaecology and Genetics
Centre, who led the study.
"These defects are unexpected and it may be
that this is just an undiscovered aspect of
biology. At the moment all we can say is that
this is part of the natural process as women
get older."
The study, which will be presented at the
European Society of Human Reproduction
and Embryology, analysed more than 100
egg cells from 34 couples undergoing IVF
treatment. The average maternal age was
40.
Scientists screened the chromosomes of the
eggs and structures known as "polar bodies"
that result from a type of cell division known
as meiosis. Meiosis is a specialised form of
division that results in eggs with half the
normal complement of chromosomes –
crucial to ensuring that the fertilised egg has
the full complement of 46 chromosomes
when it fuses with a sperm cell.
The first stage of meiosis occurs when the
woman's ovary is developing in the foetus
before birth, when the dividing chromosomes
are held together by a kind of cellular "glue"
ready for the second stage of division at
ovulation.

Carry out a survey using
published information from  Now using the research
write up a small report
the Internet on the rising
(using the information
number of mothers
we have discusses)
struggling to conceive a
about the genetic
child. Why are women
defects that some IVF
waiting longer to conceive
treatment is causing
a child? What are the
embryos.
environmental/biological
and economic factors that
are affecting these
statistics?
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
False Security
People who do not receive adequate information or
counseling about the limitations of genetic testing
may falsely assume that a negative test result
eliminates their risk for developing a disease. Many
genetic tests check for the most common gene
mutations responsible for a disease, but do not rule
out the possibility of a person developing that
disease.
Abortion rate being increased
Religion dictating /objecting to the ethics of
interfered selection of births
16-18 weeks Amniocentesis – this can cause natural
abortion
Timing considerations – 24 weeks is the limit for
abortion, at 26 weeks an infant can survive
Parental rejection of fetus due to stress
Bad karma – in some regions
legal aspects – the unborn rights of a child
Incapable adults not being able to make the correct
decisions due to metal illness
Consent from both parents (sometimes grandparents
have taken sons and daughters to court over their
rights as grandparents.
Concerns About Discrimination – if genetics
abnormalities are found out could you be
discriminated against during health insurance (US
and other countries mainly)
Designer babies – Victoria Beckham having a girl
recently?
China – only allowed one child , all families want
boys.
Adoptions
Individual choice can be made to go ahead or
terminate a pregnancy.
What tests are carried out
1.
9-10 weeks in the US chorion-biopsy (The basic
invasive prenatal diagnostic tests consist of puncture
of the uterus to obtain amniotic fluid (amniocentesis),
the removal of placentary tissue (chorion biopsy) or
obtaining blood from the umbilical cord (umbilical
blood sampling). Villious chorion biopsy
2.
Pre-implantation genetic diagnosis - People who
discover before starting a family that both partners
are carriers have several options. They may choose
to stay together but not to have any children. They
may decide to separate and find a different partner.
They may choose to stay together and have
prenatal diagnosis in each pregnancy to check if
the baby is affected. Or they may decide to go
ahead with having children without prenatal
diagnosis, and accept what comes.
A new possibility for people who want to stay
together but do not want to consider prenatal
diagnosis and termination is pre-implantation
genetic diagnosis (PGD or sometimes PIGD). This is a
procedure where the woman's eggs are fertilised by
her partner's sperm using in vitro fertilisation (IVF), a
procedure normally used to treat infertility. Before the
embryos are placed in the mother's womb, they can
be screened for genetic conditions. The aim is to
ensure only those embryos which are not affected
by a sickle cell disorder or beta thalassaemia major
are implanted.
1.
http://www.youtube.com/watch?v=P_vBDSH3bg0&feature=related
Amniocentesis represents an additional invasive
prenatal diagnostic possibility. Here in the 13th – 15th
WoP (15 - 17 weeks after the LMP) 10 - 20 ml of
amniotic fluid is obtained via a puncture. This
examination is performed with ultrasound supervision
in order to reduce the danger of hitting the fetus or
placenta and thereby harming the gestation .
All pregnant women should be
offered the triple screen, but it
is recommended for women
who:


How is the triple screen test performed?

The triple screen test involves drawing
blood from the mother which takes
about 5 to 10 minutes. The blood
sample is then sent to the laboratory for
testing. The results usually take a few
days to receive.
What are the risks and side effects to the
mother or baby?

Except for the discomfort of drawing
blood, there are no known risks or side
effects associated with the triple
screen test.
When is the triple screen test performed?

The triple screen test is performed
between the 15th and 20th week of
pregnancy although results obtained in
the 16th -18th week are said to be the
most accurate.




Have a family history of birth defects
Are 35 years or older
Used possible harmful medications or
drugs during pregnancy
Have diabetes and use insulin
Had a viral infection during pregnancy
Have been exposed to high levels of
radiation
What does the triple screen test look for?
The triple screen is measuring high and low levels of AFP
and abnormal levels of hCG and estriol. The results are
combined with the mother's age, weight, ethnicity and
gestation of pregnancy in order to assess probabilities of
potential genetic disorders.
High levels of AFP may suggest that the developing baby
has a neural tube defect such as spina bifida or
anencephaly.
However, the most common reason for elevated AFP levels
is inaccurate dating of the pregnancy.
Low levels of AFP and abnormal levels of hCG and estriol
may indicate that the developing baby has Trisomy 21(
Down syndrome), Trisomy 18 (Edwards Syndrome) or
another type of chromosome abnormality.
Although the primary reason for conducting the test is to
screen for genetic disorders, the results of the triple screen
can also be used to identify:
http://www.prolifecampaign.ie/
Task – You are requested to
compile a newspaper article
giving people all the pros and
cons of stem cell researchImages, notes and QWC in your
arguments for and against could
also be included in your report.
Why is there controversy involving
stem-cell research?
There are two different kinds of stem cells:
adult stem cells (ASC) and embryonic stem
cells (ESC). Adult stem cells can be found in
the blood, bone marrow, skin, brain, liver,
pancreas, fat, hair follicle, placenta,
umbilical cord and amniotic fluid.
As well as showing great scientific promise in
repairing damaged organs and tissues,
adult stem cell research is ethically nonproblematic. However, embryonic stem cell
research (ESCR) requires the destruction of
an embryo, which is a human being at the
beginning of life.
http://thegreengeeks.wordpress.com/2011/03/08/why-im-horrifiedby-the-pro-life-campaign/
Finding cures we can all live with!
There has been a lot of publicity
about the potential of stem cell
therapies in curing chronic diseases
and disabilities. These breakthroughs
in stem cell science are exciting and
heartening. Much of the coverage,
however, has blurred the distinction
between destructive human
embryonic research and the
perfectly ethical adult stem cell
research.
So far, all the scientific
breakthroughs are in the field of
adult stem cell research.
Nonetheless, the campaign for
public funds to allow research that
destroys living human embryos
continues unabated.