Transcript Medical Genetics

Medical Genetics
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Genetic Counseling
Medical Genetics
Genetic counseling is the
process
• evaluating family history and medical
records
• ordering genetic tests
• evaluating the results of this investigation
• helping parents understand and reach
decisions about what to do next
Medical Genetics
Genetic tests are done by
analyzing small samples of blood or
body tissues. They determine
whether you, your partner, or your
baby carry genes for certain
inherited disorders.
Medical Genetics
1. Genetic Counselors
Genetic counselors are health
professionals with specialized
graduate degrees and experience in
the areas of medical genetics and
counseling.
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Most enter the field from a
variety of disciplines, including
biology, genetics, nursing,
psychology, public health and social
work.
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Genetic counselors work as
members of a healthcare team,
providing information and support to
families who have members with
birth defects or genetic disorders and
to families who may be at risk for a
variety of inherited conditions.
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They identify families at risk,
investigate the problem present in
the family, interpret information
about the disorder, analyze
inheritance patterns and risks of
recurrence, and review available
options with the family.
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Genetic counselors also provide
supportive counseling to families,
serve as patient advocates, and refer
individuals and families to
community or state support services.
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They serve as educators and
resource people for other healthcare
professionals and for the general
public.
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Some counselors also work in
administrative capacities. Many
engage in research activities related
to the field of medical genetics and
genetic counseling.
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2. Who Should See One
Most couples planning a
pregnancy or who are expecting
don't need genetic counseling.
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About 3% of babies are born
with birth defects each year,
according to the U.S. Centers for
Disease Control and Prevention - and
of the malformations that do occur,
the most common are also among
the most treatable.
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Cleft palate and clubfoot, two of
the more common birth defects, can
be surgically repaired, as can many
heart malformations.
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The best time to seek genetic
counseling is before becoming
pregnant, when a counselor can help
assess your risk factors. But even
after he become pregnant, a meeting
with a genetic counselor can still be
helpful.
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For example, several babies have
been diagnosed with spina bifida
before birth. Recent research
suggests that delivering a baby with
spina bifida via cesarean section can
minimize damage to the baby's spine
- and perhaps reduce the likelihood
that the child will need a wheelchair.
Medical Genetics
You should consider genetic counseling
if any of the following risk factors apply to
you:
(1) if a standard prenatal screening test
(such as the alpha fetoprotein test) yields
an abnormal result
(2) if an amniocentesis yields an unexpected
result (such as a chromosomal defect in the
unborn baby)
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(3) if either parent or a close relative has an
inherited disease or birth defect
(4) if either parent or a close relative has an
inherited disease or birth defect
(5) if either parent already has children with
birth defects or genetic disorders
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(6) if the mother-to-be has had two or
more miscarriages or babies that
died in infancy
(7) if the mother-to-be will be 35 or
older when the baby is born
Medical Genetics
Chances of having a child with
Down syndrome increase with the
mother's age: a 35-year-old woman
has a one in 350 chance of
conceiving a child with Down
syndrome. This chance increases to
one in 110 by age 40 and one in 30
by age 45.
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(8) if parents are concerned about
genetic defects that occur frequently
in their ethnic or racial group
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For example, couples of African
descent are most at risk for having a child
with sickle cell anemia; couples of central
or eastern European Jewish (Ashekenazi),
Cajun, or Irish descent may be carriers of
Tay-Sachs disease; and couples of Italian,
Greek, or Middle Eastern descent may
carry the gene for thalassemia, a red
blood cell disorder.
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3. What to Expect During a Visit
Before he meet with a genetic
counselor in person, you'll be asked
to gather information about his
family history.
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The counselor will want to know of
any relatives with genetic disorders,
multiple miscarriages, and early or
unexplained deaths.
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The counselor will also want to
look over his medical records,
including any ultrasounds, prenatal
test results, past pregnancies, and
medications he may have taken
before or during pregnancy.
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If more tests are necessary, the
counselor will help him set up those
appointments and track the
paperwork. When the results come in,
the counselor will call him with the
news. Often, the counselor will
encourage him to come in for a
discussion.
Medical Genetics
The counselor will study his
records before meeting with him, so
he can make the best use of his time
together. During his session, he or
she will go over any gaps or potential
problem areas in his family or
medical history.
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The counselor can then help him
understand the inheritance patterns
of any potential disorders and help
assess his chances of having a child
with those disorders.
Medical Genetics
He or she will distinguish between risks
that every pregnancy faces and risks that
he personally faces. Even if he discovers
he has a particular problem gene, science
can't always predict the severity of the
related disease. For instance, a child with
cystic fibrosis can have debilitating lung
problems or, less commonly, milder
respiratory symptoms.
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4. After Counseling
He and his family will have to
decide what to do next. Genetic
counselors help him to understand
his options and adjust to the
difficulties and uncertainties he faces.
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If he has learned prior to conception that he and/or
his partner are at high risk for having a child with a severe
or fatal defect, his options might include:
• pre-implantation diagnosis
• using donor sperm or donor eggs
• adoption
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If he has received a prenatal diagnosis of a
severe or fatal defect, his options might include:
• preparing himself for the challenges
you'll face when he have your baby
• fetal surgery to repair the defect before
birth
• ending the pregnancy
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For some families, knowing that
they'll have an infant with a severe
or fatal genetic condition seems too
much to bear. Other families are able
to adapt to the news - and to the
birth - remarkably well.
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Genetic counselors can share the
experiences they've had with other
families in your situation. But they
will not suggest a particular course
of action.
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A good genetic counselor
understands that what is right for
one family may not be right for
another.
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Genetic counselors can, however,
refer he to specialists for further help.
For instance, many babies with Down
syndrome are born with heart
defects.
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The counselor might encourage
him to meet with a cardiologist to
discuss heart surgery, and a
neonatologist to discuss the care of a
post-operative newborn.
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Genetic counselors can also
refer he to social workers, support
groups, or mental health
professionals to help he adjust to
and prepare for your complex new
reality.