tay sachs - 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 01-17-2012
USMLE Forums Addict
 
Steps History: Not yet
Posts: 191
Threads: 96
Thanked 270 Times in 97 Posts
Reputation: 280
Default tay sachs

A girl born to parents of eastern Mediterranean Jewish descent is brought to the pediatric neurology clinic. She appeared normal at birth and is now 6 months of age. There is a loss of peripheral vision and an abnormal startle response to auditory stimuli. She has suddenly shown a loss of coordination and has lost some responsiveness to her environment. She has a cherry-red spot on her macula. Treatments to cure this disease might focus on developing therapies that would do which one of the following?
A.
Stimulate ganglioside GM2 production

B.
Stimulate synthesis of GM2 by the rough endoplasmic reticulum (RER)

C.
Stimulate hexosaminidase production

D.
Stimulate transport of ganglioside GM2 to the lysosome

E.
Remove mannose 6-phosphate from hexosaminidase
Reply With Quote Quick reply to this message



  #2  
Old 01-17-2012
USMLE Forums Addict
 
Steps History: Not yet
Posts: 191
Threads: 96
Thanked 270 Times in 97 Posts
Reputation: 280
Default

child in the scenario suffers from Tay-Sachs disease, a lysosomal storage disease. Lysosomes contain an array of specific hydrolases. In Tay-Sachs disease, hexosaminidase A is deficient, resulting in the buildup of GM2 ganglioside in lysosomes leading to mental retardation, blindness, and mortality. A pharmacological approach would target reducing GM2 ganglioside levels by increasing hexosaminidase A activity (answer c). Increase in GM2 levels (answers a and b) or increased transport (answer d) to a lysosome deficient in hexosaminidase would worsen the disease. The table on the next page summarizes the enzyme deficiencies and resulting effects in some of the more prominent lysosomal disorders. Mannose 6-phosphate and its receptor are involved in the trafficking of proteins to the lysosomal compartment. Removal of mannose 6-phosphate (answer e), as occurs in inclusion-cell (I-cell) disease, would result in default of lysosomal enzymes to the secretory pathway, and the hexosaminidase deficiency would worsen.
Reply With Quote Quick reply to this message
The above post was thanked by:
Hitman (01-17-2012)
  #3  
Old 01-17-2012
USMLE Forums Addict
 
Steps History: Not yet
Posts: 177
Threads: 25
Thanked 75 Times in 55 Posts
Reputation: 87
Default

Good question. Answer : C
Reply With Quote Quick reply to this message



Reply

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
The chance of getting homozygous normal HLA compatible sibling for this girl with Tay Sachs! laurier USMLE Step 1 Forum 19 12-09-2011 11:10 AM
Tay sachs genetic counseling docoftheworld USMLE Step 2 CK Forum 1 06-09-2011 05:23 AM
Tay Sachs and Niemann Pick In-N-Out USMLE Step 1 Forum 4 01-22-2011 09:09 PM
Tay Sachs disease jackat1000 USMLE Step 1 Mnemonics 6 04-16-2010 08:38 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)