TAR-thrombocytopenia & absent radius syndrome

[karenk]

Thrombocytopenia and absent radius syndrome--
what is the most likely mode of inheritance and why?

Parents ( both are healthy) have 6 kids---only 2 are healthy. One child(Pete) is allergic to cows milk and has a minor heart defect. If Pete marries a woman who is homozygous for the wild type allele of the gene that causes this condition, what is the probibilty that a child wil be a carrier?

If you need more info please email at karenkessler@charter.net
thank you

[LilKim]

hey... the info about the allergy to cow's milk is irrelevant ....

I could guess the answer to this question .. but I don't want to do that. (Cuz i want to make sure that i'm right... and I want to SHOW you how i came to the conlusion)

Is there more info?
- what are the genotypes or/and phenotypes of the 4 other children?
- Is a heart defect a symptom of thrombocytopenia & absent radius syndrome??

From that info we can determine if:
- autosomal recessive
-sex-linked recessive
- Dominant (with different degrees of pentrance)
... etc.

- kim

p.s. you could probably do an internet search on the topic and learn about the disease... and the mode of inheritance. (however, knowing the facts won't help you solve this kinda question... the next time you see it)

[karenk]

This is the info the teacher gave us.

THROMBOCYTOPENIA AND ABSENT RADIUS SYNDROME
 
Marjorie and Joe Winthrop are healthy, but only two of their six children are well.  Michel, the eldest, was born without arms, and has an abnormal heart.  Jacob, born next, is healthy.  Marianne, the third eldest, suffered near-constant stomach cramps until her parents realized that she was allergic to cow's milk.  She also has impaired blood clotting and excess eosinophils, a type of white blood cell.  The next child, Adam, is healthy.  The youngest two children, Mira and Pete, are twins.  Pete is allergic to cow's milk and has a minor heart abnormality.  When Pete's cardiologist asks for a family history, and Joe mentions the various symptoms of the children, the doctor realizes that the family has thrombocytopenia and absent radius syndrome (TAR).  Marjorie and Joe's parents do not have any of these symptoms.
 
SOURCE:  OMIM 274000
 
 
 
2.    The most likely mode of inheritance is ? because?
 
3.    If Pete marries a woman who is homozygous for the wild type allele of the gene that causes this condition, the probability that a child of theirs would be a carrier is?
                                    .

[canalon]

Maybe you could start to think by yourself. Tell us what you think, what are the things you have problems with etc... and we will help. But WE ARE NOT a homework service.