Trinucleotide repeats

[DrPak]

---

Members don't see this ad.

Do we really have to know the actual nucleotide repeats in the different repeat disorders? I had a question on usmlerx which required me knowing that.

In case we do, I gather the important ones are:

Huntington's=CAG
Myotonic Dystrophy=CTG
Friedrich's ataxia=GAA
Fragile X=CCG.

 

[39094]

Do we really have to know the actual nucleotide repeats in the different repeat disorders? I had a question on usmlerx which required me knowing that.

In case we do, I gather the important ones are:

Huntington's=CAG
Myotonic Dystrophy=CTG
Friedrich's ataxia=GAA
Fragile X=CCG.

I would think knowing them that specifically would not be important. Again, the general concept is important as is understanding the concept of anticipation by trinucleotide repeat expansion. (Understand why it happens and what the result is)

If you actually got a question on the real thing that expected you to tell the difference based solely on 3 nucleotides without any other clinical data that would definitely fall under the category of a WTF question. Unless you're going for a 270+ you shouldn't waste time studying for those.

 

[Rogue_Leader]

Also, what's also important is knowing the symptoms of those diseases. A lot of the time, they'd describe a disease and then ask what the genetic mechanism behind it was without ever mentioning the disease in the first place.

 

[DrPak]

The question I got was a clinical description of Huntington's and then a series of trinucleotide repeats along with the chromosome they were found in. Maybe knowing the chromosome is not a WTF question?

 

[39094]

The question I got was a clinical description of Huntington's and then a series of trinucleotide repeats along with the chromosome they were found in. Maybe knowing the chromosome is not a WTF question?

Hard to say. I didn't see anything on my exam about particular chromosomes, but it's in FA so maybe it's appeared in the past.

 

[CaptainZero]

Do we really have to know the actual nucleotide repeats in the different repeat disorders? I had a question on usmlerx which required me knowing that.

In case we do, I gather the important ones are:

Huntington's=CAG
Myotonic Dystrophy=CTG
Friedrich's ataxia=GAA
Fragile X=CCG.

No