Transcript Case05 Sex linked hemophilia

Case05 At risk for hemophilia
1. Review the four principles of sex-linked
inheritance. Which individuals
demonstrate that it affects more often in
males than females?
Males: Terry, Greg, Bill
Females: Jenny
2. Which individuals represent the idea that
the trait is not passed from father to son?
Henry doesn’t pass it to Richard
3. Which individuals represent the principle
that the trait can “skip a generation” or
more being transmitted through a series of
asymptomatic female carriers.
What’s asymptomatic?
No one really shows this principle
4. Why are none of the males in the figure
shown as carriers of hemolphilia?
Males can’t carry, they only express the
normal or recessive gene.
Carrying implies you are heterozygous for
the trait.
5. What is the probability that Marcy and
Tom will have any child with hemophilia
(either sex)
There’s a 50% chance Marcy is a Carrier
Of that 50% chance cross XHXh with XHY¼ XHXH normal female
¼ XHY- normal male
¼ XHXh carrier femal
¼ XHY- hemophilic male: ¼ of 50% is 12.5 %
6. Suppose Marcy is pregnant. She gets
an amniocentesis. Its going to be a girl.
Should she be worried that the girl will be
a hemophiliac?
No see above: Marcy can only have normal
or carrier females
Can Marcy have hemophilic Grandchildren?
Yes if she is a carrier and passes it on to her
daughter.
7. Blood typing can help determine paternity.
Suppose an unmarried woman gives birth,
charges a certain man with being the
father and sues for child support. Its on
Maury Povich. He demands blood tests.
Woman: Type A
Baby: Type A
Potential Father: Type B
Does this rule him out?
No. He could be type IBi
That would mean the baby is type IAi