Elevated Dolichol! - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 05-02-2010
USMLE Forums Newbie
 
Steps History: Not yet
Posts: 2
Threads: 1
Thanked 3 Times in 1 Post
Reputation: 13
Biochemistry Elevated Dolichol!

A 15-month-old girl is referred for ophthalmologic and neurologic follow-up by her pediatrician. The child has shown a failure to thrive, is microcephalic, exhibits myoclonic jerks, delayed psychomotor development, visual disturbance and seizures. Analysis of fibroblasts from the skin by electron microscopy confirms the presence of fingerprint inclusion bodies. Elevated levels of dolichol are found in the urine. Normally, dolichol is associated with which cellular process:

A. Sulfation in the trans compartment of the Golgi
B. O-linked glycosylation in the medial compartment of the Golgi
C. O-linked glycosylation in the cis compartement of the Golgi
D. N-linked glycosylation in the endoplasmatic reticulum
E. Sorting of proteins to the lysosome from the TGN

Reply With Quote Quick reply to this message
The above post was thanked by:
doctorF (05-04-2010), Ronald (05-02-2010), tomymajor (05-02-2010)



  #2  
Old 05-02-2010
ath.pantelis's Avatar
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 187
Threads: 4
Thanked 371 Times in 122 Posts
Reputation: 401
Default

In all probability, this girl suffers from I-cell disease, which is clinically similar to Hurler's syndrome (the latter is notorious for causing corneal clouding).

In I-cell disease (I for Inclusion bodies, as described in the question stem), the deficit lies upon the enzyme N-acetyl-glucosaminyl-phosphotransferase, which belongs to the superfamily of dolichol. As its name indicates, its role is to add mannose-6-phosphate residues to the N-terminal of peptides, in order for them to be signaled for degradation into the lysosomes. Once this enzyme is deficient, peptides that would otherwise be degraded, eventually accumulate within inclusion bodies, attributing to the cells the characteristic microscopic appearance for the disease.

So, the correct answer must be D.
Reply With Quote Quick reply to this message
The above post was thanked by:
dannyd (05-03-2010), doctorF (05-02-2010), theartofbone (05-04-2010), tomymajor (05-02-2010)
  #3  
Old 05-04-2010
USMLE Forums Scout
 
Steps History: 1+CK+CS
Posts: 68
Threads: 5
Thanked 47 Times in 29 Posts
Reputation: 57
Default

Quote:
Originally Posted by amnios View Post
A 15-month-old girl is referred for ophthalmologic and neurologic follow-up by her pediatrician. The child has shown a failure to thrive, is microcephalic, exhibits myoclonic jerks, delayed psychomotor development, visual disturbance and seizures. Analysis of fibroblasts from the skin by electron microscopy confirms the presence of fingerprint inclusion bodies. Elevated levels of dolichol are found in the urine. Normally, dolichol is associated with which cellular process:

A. Sulfation in the trans compartment of the Golgi
B. O-linked glycosylation in the medial compartment of the Golgi
C. O-linked glycosylation in the cis compartement of the Golgi
D. N-linked glycosylation in the endoplasmatic reticulum
E. Sorting of proteins to the lysosome from the TGN
I didnt even know what Dolichol is (will look up later), and glad it didnt come out on my Step 1... However, since it ends in "ol", I assumed it to be an alcohol. Knowing that Steroids, Lipids, and alcohols have a portion metabolized by the SER, option D.) was my safest guess. Sometimes one has to use street smarts to nail a Q or two. :P

Last edited by theartofbone; 05-04-2010 at 07:51 PM. Reason: typo
Reply With Quote Quick reply to this message



Reply

Tags
Biochemistry-, Pediatrics-, Step-1-Questions, Syndromes-Acronyms

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Intoxicated + Elevated Anion Gap + Envelop Shaped stuff in Urine rasheed USMLE Step 2 CK Classic Clues 2 07-09-2016 12:04 PM
Elevated Lactate and Alanine? sam01 USMLE Step 1 Forum 7 12-14-2010 07:02 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)