Baby Doe v. The Prenatal Clinic
Norris Armstrong
University of Georgia-Athens
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Baby Doe v. The Prenatal Clinic
John looked at the baby squirming in his arms. He and his wife,
Jane, had been trying to have kids for a couple of years and had
finally been successful. The pregnancy was uneventful and, though
the delivery took longer they either of them would have liked,
everyone seemed to be doing fine.
This was a new experience for John. Everything about the child he
was holding seemed so small and delicate. Even so, some things
seemed unusual. For example, the baby looked a little cross-eyed,
and its face seemed a little flat when he looked the baby from the
side. Also, the baby’s hands and feet were even smaller than he
would have expected, and the hands had a strong crease that ran
across the middle of the palms. John realized he was probably
imagining things. After all, though he had a younger brother, he
was definitely no expert on newborn babies.
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One week later…
But one week later John and Jane sat in the clinic’s conference
room in stunned silence. “I had to run some tests to be certain,”
said their doctor. “However, the results confirmed what I
suspected. Your child has Down syndrome. I am afraid there is no
cure. However, early intervention can improve the outcome you
can expect. I can give you the names and numbers for several
organizations that can give you
well
more information and
advice. There are
other resources
you can try as
………………”
John and Jane did not hear much of what the doctor said after the
diagnosis. The only thought that kept running through their minds
was, “How could this have happened?”
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The Case
You’ve been hired by a law firm to serve as an expert witness for
John and Jane’s case. To help your client and to appropriately
inform the court, you will need to explain what actually causes
Down syndrome to the jury. You will also need to explain whether
or not the clinic could have done anything that contributed to the
baby’s condition.
Since it was likely to have been many years since most of the jurors
had studied biology, one of the things you probably have to do is
give them a crash course on some basic biology.
For starters, what exactly is Down syndrome?
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Q#1: What is Down syndrome?
1. A condition caused when the mother drinks alcohol
while pregnant.
2. A form of childhood cancer.
3. A birth defect resulting in a split upper lip and
speech problems.
4. A condition caused when the baby has too many
copies of a chromosome.
5. A form of brain damage that results when the baby
receives too little oxygen during birth.
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Down syndrome
• A chromosomal disorder resulting from a partial or complete extra
copy of chromosome 21.
• Multiple developmental and health effects including:
• Short stature, distinct facial features.
• Mild to moderate physical and cognitive impairment.
• Increased risk of problems involving heart, respiratory, digestive,
hearing, vision, and/or thyroid glands.
• Trisomy 21 (95% of all cases): three complete copies in all cells.
• Mosaicism (1-2% of cases): three copies in some but not all cells.
• Translocation (3-4% of cases): partial copy of chromosome 21
attached to another chromosome.
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What are chromosomes?
•Human cell = >6 billion nucleotide base pairs (~2 meters)
•Wrapped around protein = chromatin
•DNA/protein = chromosome
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How many chromosomes do humans have?
• Humans are diploid (2n)
• Two of each chromosome, one from each parent.
• n = 23 unique chromosomes (haploid #) Curly hair
allele
• 2(n) = 46 total chromosomes
Strait hair
allele
• The two copies of each chromosome in
human cells are homologous
• Different versions - same genes in same
locations but different DNA sequence.
• Different versions (alleles) of a gene may
promote different traits (e.g. hair type).
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The diploid chromosome number in
standard laboratory mice (genus Mus) is
40. What is the n for this organism (i.e. how
many unique chromosomes does the mouse
have?
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Getting Ready
The first court date for John and Jane’s case is coming up
and it is time to start organizing your testimony. You
need to help the jury determine whether the doctors at the
clinic may have done something to cause the baby to
have the incorrect number of chromosomes.
A good place to start might be to describe how cells get
the right number of chromosomes in the first place.
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How do cells get
the right number
of chromosomes?
DNA
DNA
DNA
DNA
DNA
DNA
DNA
Cell Division
1. Duplicate cell components
• Organelles
• Cytoplasm
• Chromosomes
2. Separate the material into
two daughter cells
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DNA Packaging – S Phase
Sister
Chromatids
centrosome
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Interphase
Mitosis
•Prophase
•Metaphase
•Anaphase
•Telophase
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Q#3: If you investigated cells from
a lab mouse with 40 chromosomes
you would find a total of __ sister
chromatids first after the ___ stage.
1.
2.
3.
4.
10: G1
20: G2
40: M
80: S
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Families: similar yet different. Why?
Asexual Reproduction
•Single parent
•Offspring identical to each other and parent
Sexual Reproduction
•Two parents
•Offspring are unique
•Offspring are similar to each other and parents
•Combine DNA from two individuals
•Combines characteristics of both individuals
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Why do diploid organisms need
to have specialized sex cells?
• Sex cells (gametes: sperm or egg) allow traits
to be combined from two organisms
2n
(46)
+
2n
(46)
4n = 92
too many
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Sexual Reproduction
• Gametes have only one of each chromosome
• Requires special cell division: Meiosis
•Diploid cells (2n)
Gametes (n)
•Takes place in gonads (testis, ovary)
n (23)
+
n (23)
2n = 46
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How is Meiosis different from Mitosis?
Mitosis
Cells divide 1x
Meiosis
Cells divide 2x
2n
2n
2n
2n
n
n
Diploid Cells
n n n n
Haploid Cells
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Mitosis
Identical cells
Meiosis
Different cells
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Mitosis
Cell division is
over
Meiosis
Cells divide again;
sister chromatids line up
Done
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21
How many unique gametes can a cell with
two pairs of chromosomes make?
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Why bother?
•For humans with 23 pairs of chromosomes?
•(2)23
> 8 million different possible gametes
•For a couple
•possible unique offspring
•(8 million) x (8 million) = (64,000,000,000,000)
But wait! There’s more!
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Crossing over enables even greater variety
• Exchange of equivalent sections between homologous
chromosomes.
• Occurs at random locations along chromosome.
• Creates new versions of chromosomes.
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Q#4: The cell to the right shows a diploid organism with
two chromosomes (2n=2). The pictures below show
some of the steps this cell may go through
during mitosis or meiosis.
A.
D.
B.
E.
F.
C.
G.
H.
Place the appropriate steps in order for a cell going through
mitosis. (Note: you may use just some or all of the steps.)
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Q#5: The cell to the right shows a diploid organism with
two chromosomes (2n=2). The pictures below show
some of the steps this cell may go through
during mitosis or meiosis.
A.
D.
B.
E.
F.
C.
G.
H.
Place the appropriate steps in order for a cell going through
meiosis. (Note: you may use just some or all of the steps.)
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Parent #2
Parent #1
Q#6: The different copies
of chromosome 21 in
John and Jane are
shown to the right.
Which of the following is a normal gamete that
might be produced by either John or Jane?
1
2
3
4
5
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Comparison of Divisions
Mitosis
Meiosis
2
Number of
divisions
1
Number of
daughter cells
2
4
Yes
No
Same as parent
Half of parent
Where
Somatic cells
Germ cells
When
Throughout life
At sexual maturity
Growth and
repair
Sexual reproduction
Genetically
identical?
Chromosome #
Role
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What went wrong?
Now that you’ve explained to the jury how cells normally
receive the correct number of chromosomes, you need to
explain whether this did not happen with John and Jane’s
baby because of something the clinic doctor’s may have
done.
What can cause a cell to inherit the incorrect number of
chromosomes?
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Normal Meiosis
Non-Disjunction
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Parent #1
Parent #2
Down syndrome
The different copies of
chromosome 21 for John,
Jane, and their baby are
shown here.
Child
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Q#7: If you were on the jury for the
malpractice trial of the doctor, what
would you decide?
1. The doctor must have done something wrong to
cause cell division to have malfunctioned.
2. The doctor could not have done anything to cause
the problem.
3. It is impossible to tell if the doctor could be at fault.
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Case closed?
You’ve presented pretty conclusive evidence that the
clinic was not responsible for causing Down syndrome in
John and Jane’s baby. However, now comes the trickiest
part of the trial. Should the clinic have alerted the couple
that something might be wrong before the baby was
delivered? How could the doctors have known that the
baby might have be born with Down syndrome?
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How is Down syndrome detected?
Karyotyping
•Isolate chromosomes during fetal cell division.
•Arrange in pairs according to size.
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Q#8: Does this person have Down
syndrome?
A. Yes
B. No
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A karyotype can be performed by collecting cells from the
developing embryo in the first trimester using one of two
procedures. Techniques for doing this slightly increase the risk of
miscarriage (0.5-1.0%). Jane’s family had no history of Down
syndrome, but John had a cousin with the disorder. A chart
showing Jane’s age (red line) and the risk of having a Down
syndrome child is shown below.
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Q#8: Is the clinic liable for not
testing for Down syndrome?
1. Yes, the clinic should have tested the baby for Down
syndrome.
2. It is liable only if the clinic failed to follow suggested
guidelines for when to perform the test.
3. Yes, it doesn’t matter if the clinic was at fault or not.
4. No, the clinic should not be held at fault for
something beyond its control.
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In 2001, France's high court of appeals ruled that the
parents of a boy who has Down syndrome should be
compensated because the situation was not detected by the
doctor during the pregnancy.
In 2004, the Utah Supreme Court ruled that the parents of a
4-year-old girl with Down syndrome cannot sue a doctor
for misreading prenatal tests designed to identify the
disability.
In 2007, a California court awarded a 34-year-old woman
damages because the medical center failed to offer her the
opportunity to undergo amniocentesis and Chorionic Villus
Sampling early in the course of her pregnancy.
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Historically, women over age 35 or who are at risk of
having a child with Down syndrome are encouraged to
have amniocentesis and CVS to test for this abnormality.
However, because most pregnancies occur in younger
couples, 80% of Down syndrome cases occur with women
under age 35. Down syndrome occurs in one out of every
800-1000 live births.
In 2007, the American College of Obstetricians and
Gynecologists recommended that every pregnant woman,
regardless of age, be offered a choice of tests for this
common birth defect.
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