beta thalassemia

[soon2Bmd2005]

hey all,
have checked multiple sources and can't figure out what the mutation in beta thal is due to. some say splice site (i think kaplan), some say frame shift (some website), some say stop codon (goljan). i'm guessing there are many types of mutations...but which one are the Step 1 people looking for. Any opinions? Thanks!

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[Tristy]

Well, I'm looking at Goljan right now and what he says is that:
1) beta+: splicing defect
2) beta 0: non-sense mut-->stop codon-->premature termination of prot synthesis OR absent synthesis

So basically we get decreased or totally absent synthesis of beta globin.

That's what we got told in class as well (if I remember correctly). Or I could be totally wrong...

 

[SeventhSon]

hey all,
have checked multiple sources and can't figure out what the mutation in beta thal is due to. some say splice site (i think kaplan), some say frame shift (some website), some say stop codon (goljan). i'm guessing there are many types of mutations...but which one are the Step 1 people looking for. Any opinions? Thanks!

beta thalassemia by definition means decreased or absent beta chain synthesis. There could be many mutations leading to this, of which the poster above outlined several. I am unaware of epidemilogical data talking about different particular point mutations/deletions etc.

 

[docmd2010]

That's definetily a good factoid to know for the step 1. Another thing that they really like to ask about beta thal is iron overload resulting from blood transfusions. The basic presentation is similar to this:

Patient comes in with fatigue, lethargy, blah blah blah, and increased hemolysis. Serum analysis reveals elevated serum ferritin levels, decreased TIBC and increased saturation. The patient has a hx of blood transfusions And the question usually asks something related to beta thal, (how many mutations?, where is the mutation (splicing site) etc. etc.

 

[soon2Bmd2005]

same question for tay sachs...some sources say splice site mutation (i think one of the high yields) and some say frameshift (goljan..i think)...any thoughts?

 

[ertugrul]

same question for tay sachs...some sources say splice site mutation (i think one of the high yields) and some say frameshift (goljan..i think)...any thoughts?

Why should be only and only one mechanism that leads a specific disorder