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Old 11-09-2009
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DNA Which Chromosome?

A 4-month-old female is brought to her pediatrician by her mother who is concerned about some photographs she recently had developed. In the photographs, only the child’s right eye demonstrates a red reflex. Examination of the left eye confirms absence of a red reflex. Which of the following mechanisms is most likely involved?

a- Deletion in the long arm of chromosome 13
b- Deletion in the short arm of chromosome 5
c- Deletion of the short arm of chromosome 11
d- Nondisjunction of chromosome 18
e- Nondisjunction of chromosome 21
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  #2  
Old 11-09-2009
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aaaaaaaaaaa
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  #3  
Old 11-09-2009
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Quote:
Originally Posted by ahmad_jafar View Post
aaaaaaaaaaa
Correct! but do you know why?
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  #4  
Old 11-09-2009
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Default Why..

Because of a Retinoblastoma cataract?

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Originally Posted by indrag View Post
Correct! but do you know why?
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Old 11-09-2009
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Originally Posted by ashishkabir View Post
Because of a Retinoblastoma cataract?
There's no cataract in retinoblastoma
It's the retinoblastoma itself that causes the loss of red reflex (Leukocoria)

Option C is the real distractor as it's pointing to another tumor suppressor gene of Wilm's tumor which may cause aniridia (WAGR association)
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  #6  
Old 11-09-2009
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Right... leukocoria, not cararact. Thanks. True about the aniridia and WAGR. Good question.

Quote:
Originally Posted by YoramFishke View Post
There's no cataract in retinoblastoma
It's the retinoblastoma itself that causes the loss of red reflex (Leukocoria)

Option C is the real distractor as it's pointing to another tumor suppressor gene of Wilm's tumor which may cause aniridia (WAGR association)
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  #7  
Old 05-09-2013
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retinoblastoma
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  #8  
Old 05-09-2013
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a, because it is loss of RB gene
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Genetics-, Step-1-Questions, Syndromes-Acronyms

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