Transcript A Healthy Pregnancy

A Healthy Pregnancy
Unit Four
Genetic Problems in
Prenatal Development
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Objectives
Name and describe specific types of
Birth Defects
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Discuss the causes of Birth Defects
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Identify how birth defects can be
diagnosed and prevented
Note:
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150,000 babies are born each year
with birth defects
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1 out of 28 babies
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Birth Defects
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A Birth Defect is an abnormality present at birth, that
affects the structure or function of the body.
Premature Babies are born before their development
is complete (pregnancy less than 36 weeks or weigh less
than 5.5 lbs). They are vulnerable to infection, lung
ailments and other problems.
In some cases if prenatal development is not
proceeding normally, a miscarriage ( the natural
ending of a pregnancy before the fetus could possibly
survive) occurs.
A stillbirth is the natural ending of a pregnancy after
20 weeks.
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Causes of Birth Defects
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Some birth defects are caused by Heredity and
others by the Environment.
Heredity Defects are inherited from one or
both parents.
Environmental Defects are caused by facors in
he environment.
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Hereditary Causes
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Everyone has five or six imperfect recessive
genes among thousands that make up the
genetic blueprint.
Normal genes are usually dominant over
recessive genes.
If both parents pass on the same defective
recessive gene for a particular defect, the child
will be born with that defect.
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Hereditary Defects
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Some hereditary defects
are inherited conditions
that affect males only.
Hemophilia, a
condition that affects
blood clotting and Color
Blindness are such
conditions.
Color blindness charts
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Hemophilia
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Hemophilia is a genetic disease: Mutations
on the X chromosome result in low levels
of blood clotting factors.
The mutations that cause low levels of
clotting factor are carried recessively on the X
chromosome.
As women have two X chromosomes
(XX), the mutated gene would have to be
present on both chromosomes to cause the
disease, and this is exceedingly rare.
Since men have only one X chromosome
(XY), one copy of the mutated hemophilia
gene is enough to cause the disease, so
males who inherit the gene will
be affected.
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Cystic Fibrosis
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Cause- genetic
Description-Respiratory
and digestive problems
Below a CF Lung on
left compared to a
Healthy Lung on right
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Cystic Fibrosis - A Genetic Disorder
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Cystic Fibrosis is a genetic
disease, meaning it is caused by a
defect in the person's genes.
Cystic Fibrosis is a chronic,
frequently fatal, progressive,
genetically (inherited) disease of
the body's mucus glands. Cystic
Fibrosis primarily affects the
respiratory and digestive systems
in children and young adults .
Cystic Fibrosis affects the body's
ability to move salt and water in
and out of cells. This defect causes
the lungs and pancreas to secrete
thick mucus,
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Rh Factor - Genetic Defect
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1.
2.
A blood test is also used to
check the Rh factor in the
blood.
A person’s blood is either:
Rh positive - having a certain
protein or
Rh negative - not having that
protein
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Problems can arise if he
mother’s blood lacks the
protein and the fetus’s blood
has it. ( the fetus may inherit
this blood factor from the
father).
The mothers blood will
produce anti-bodies that
attack the protein in the
fetus’s blood as though it
were a germ.
Doctors can inject a
chemical into the mother o
prevent the problem from
arising.
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Other Genetic
Disorders
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Special therapy and
schooling are part
of treatment for
Down’s Syndrome
Children
Down’s Syndrome
May include mental retardation,
delayed development, heart
defects
Chromosomes are made up of
DNA and protein & are located
in the nucleus of each cell.
Because chromosomes are
carriers of genetic material,
abnormalities in chromosome
structure (such as missing or extra
copies or gross breaks), can result
in disease.
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Down syndrome
Down syndrome or
trisomy 21 is a common
disorder that occurs
when a person has three
copies of chromosome
21. One in every 650
births has this condition.
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Cleft Lip / Cleft Palate
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A cleft lip is a separation of the two sides of the lip.
The separation often includes the bones of the upper
jaw and/or upper gum.
A cleft palate is an opening in the roof of the mouth
in which the two sides of the palate did not fuse, or join
together, as the unborn baby was developing
One of every 700 newborns is affected by cleft lip
and/or cleft palate.
Cleft lip and cleft palate are birth defects, which occur
very early in pregnancy. The majority of clefts appear to
be due to a combination of genetics and environmental
factors.
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Cerebral Palsy
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Cerebral Palsy (CP) is a term
used to describe a group of
disorders affecting body
movement and muscle coordination.
Development of the brain
starts in early pregnancy and
continues until about age three.
Damage to the brain during this
time may result in cerebral palsy.
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MUSCULAR DYSTROPHY
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Muscular Dystrophy (MD) is
the name of a group of muscle
disorders that are characterized
by progressive weakness and
wasting of the voluntary
muscles that control body
movement. As muscle tissue
weakens and wastes away, it is
replaced by fatty and
connective tissue.
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MUSCULAR DYSTROPHY
Cause Heredity [ female male]
 Most types of MD are hereditary .
The most common form is
transmitted by female carriers of the
gene but affects only males.
Description Weakness and shrinkage of the
muscles
 Death before adulthood
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PKU
What is Phenylketonuria (PKU)?
 PKU is a genetic disorder which prevents
the normal use of protein food. Mental
retardation can result. To be affected by
this hereditary condition (carried on a
recessive gene) a child must have two
copies of the defective gene (one from
each parent).
 The condition can be treated with a high
degree of success if diagnosed shortly
after birth. A special diet can reduce or
prevent brain damage.
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The Genetics of PKU
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Genes can sometimes contain mistakes so that
the cell can't read them properly. We can call this
a "non-working gene".
The gene that is important in PKU is located on
the chromosome pair number 12.
People with PKU have two non-working copies
of this PKU gene. One copy they inherited from
mom, and the other from dad. Usually, parents
don't even know they are carriers of PKU until
they have a baby who has PKU.
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Sickle-Cell Anemia
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Sickle cell anemia occurs
when a person inherits two
abnormal genes (one from
each parent) that cause their
red blood cells to change
shape. Instead of being
flexible and round, these cells
are more rigid and curved in
the shape of the farm tool
known as a sickle
1. Normal Red Blood Cells
2. Sickled Red Blood Cells
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Sickle Cell Anemia
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Sickle cell anemia is a
hereditary disorder that
mostly affects people of
African ancestry, but also
occurs in other ethnic
groups, including people who
are of Mediterranean and
Middle Eastern descent .
People with sickle cell anemia
can experience complications
from blood circulation and
infection-fighting problems .
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Tay-Sachs Disease
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Infants with Tay-Sachs disease appear
to develop normally for the first few
months of life. Then, as nerve cells
become distended with fatty material,
a relentless deterioration of mental
and physical abilities occurs. The child
becomes blind, deaf, and unable to
swallow. Muscles begin to atrophy and
paralysis sets in.
Tay-Sachs disease affects
children who inherit two
copies of an altered gene
from their carrier parents.
Carriers of Tay-Sachs
disease are not affected
themselves, because they
have a working gene as well
as an altered one.
Carrier parents have a onein-four chance of having an
affected child, a one-in-two
chance of having a child
who is an unaffected carrier
and a one-in-four chance of
having a child who doesn't
carry any altered genes. 21
Spina Bifida
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The risk of having a
baby with spina bifida is
2-3 percent.
It is well established that
taking folic acid prior to
pregnancy as well as in
the first trimester will
decrease spina bifida in
the general population by
70 percent.
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Spina Bifida
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Spina bifida usually is
an isolated birth defect.
Although scientists
believe that genetic and
environmental factors
may act together to cause
this.
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Genetic Counseling
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Some genetic or chromosomal
defects can be predicted by
genetic counseling.
It tells parents in advance the
statistical odds that their
children will have certain
diseases or defects.
It explains options and risks.
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Prenatal Tests
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If a woman is pregnant,
her doctor may request
tests to determine birth
defects.
Ultrasound is a
technique of using
sound waves to make a
video of an unborn baby
to check for specific
health problems.
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Prenatal Tests
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Amniocentesis is the
process of withdrawing a
sample of he amniotic
fluid surrounding the
unborn baby with a
special needle and testing
that fluid for indications
of specific birth defects
or other health problems.
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