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Old 09-19-2012
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Default Duchenne muscular dystrophy - what molecular consequence?

An 8-year-old boy diagnosed with Duchenne muscular dystrophy (DMD), an X-linked disorder, has two family members who underwent mutation analysis that identified single base pair substitution in the middle of intron 1 of the dystrophin gene, which differs from the mutation found in the patient. What is the most likely consequence of the mutation in these family members?

a) Increase in mRNA
b) Increase in mRNA half-life
c) No change in gene function
d) Reduction in mRNA
e) Reduction in protein translated

Please provide an explanation along with your answer
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Old 09-19-2012
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my answer is E) reduction in protein translated

i'm thinking their mutations are due to polyadenylation sites...so spliced differently...if polyadenylation occurs many times they lead to formation of noncoding RNA's formation....which cannot be translated into proteins
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Old 09-19-2012
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An 8-year-old boy diagnosed with Duchenne muscular dystrophy (DMD), an X-linked disorder, has two family members who underwent mutation analysis that identified single base pair substitution in the middle of intron 1 of the dystrophin gene, which differs from the mutation found in the patient. What is the most likely consequence of the mutation in these family members?

a)Increase in mRNA
b) Increase in mRNA half-life
c) No change in gene function
d) Reduction in mRNA
e) Reduction in protein translated

mutation in the middle of intron will cause splice site mutation.Splice site mutations lead to production of larger proteins with altered functions.
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Old 09-19-2012
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Default C. No change in gene funtion

Quote:
Originally Posted by Casandra View Post
An 8-year-old boy diagnosed with Duchenne muscular dystrophy (DMD), an X-linked disorder, has two family members who underwent mutation analysis that identified single base pair substitution in the middle of intron 1 of the dystrophin gene, which differs from the mutation found in the patient. What is the most likely consequence of the mutation in these family members?

a) Increase in mRNA
b) Increase in mRNA half-life
c) No change in gene function
d) Reduction in mRNA
e) Reduction in protein translated

Please provide an explanation along with your answer
There is mutation in Intron and as i remember introns don't code for protein and even we splice it out while mRNA transcription.
So i will go with " No change in gene function"
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Quote:
Originally Posted by koolkiller88 View Post
There is mutation in Intron and as i remember introns don't code for protein and even we splice it out while mRNA transcription.
So i will go with " No change in gene function"
introns are generally spliced

but if mutation in intron occurs...it cannot be spliced and lead to formation of abnormal protein
so according to you,,how the pt get DMD in this question if mutation exist in intron..
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Quote:
Originally Posted by venky2600 View Post
introns are generally spliced

but if mutation in intron occurs...it cannot be spliced and lead to formation of abnormal protein
so according to you,,how the pt get DMD in this question if mutation exist in intron..
I'll post the right answer in few hours as I want more people to see and answer the question but please note (@venky2600) that what you're talking about is a splicing site NOT an intron. If there's a mutation in a splicing site the process of the excision will be disturbed (like in beta-talassemia).
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Quote:
Originally Posted by Casandra View Post
I'll post the right answer in few hours as I want more people to see and answer the question but please note (@venky2600) that what you're talking about is a splicing site NOT an intron. If there's a mutation in a splicing site the process of the excision will be disturbed (like in beta-talassemia).
ya, got it...thanks...!
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i would go with answer c.......as intron is noncoding region of dna..........
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substitution alters the reading sequence of the gene(DNA) like frameshift mutation

Altered mRNA -- may lead to early terminaton of protien

I'm guessing e) reduced protein
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Default C

I think no change occurs...introns are noncoding, spliced, no effect
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A. Altered splice site mutation cause increase in mRNA
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Old 09-20-2012
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Default correct answer :)

The answer is c) No change in gene function

No change is expected in the function of this gene because of this inconsequential mutation. Introns are removed and will have no affect on the protein translated.
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Quote:
Originally Posted by Casandra View Post
The answer is c) No change in gene function

No change is expected in the function of this gene because of this inconsequential mutation. Introns are removed and will have no affect on the protein translated.
Never been so happy with such a random guess...hehehe


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