Trinucleotide Repeat Genetics - 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 12-24-2012
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 106
Threads: 35
Thanked 17 Times in 10 Posts
Reputation: 27
Genetics Trinucleotide Repeat Genetics

A 16 yr boy is brought to physical for routine exam. He has lifelong history of developmental delay and unusual movements such as hand flapping. He has meager vocubulary. His 2 maternal uncle has mental retardation. PE - coarse facial feature and macroorchidism. DNA testing shows expansion of trinucleotide repeat. The pt comes from a family of 4 daughters. If the parents appear healthy, on average how many of daughters are most likely carrier of this gene mutation?
A 0
B 1
C 2
D 3
E 4
Reply With Quote Quick reply to this message



  #2  
Old 12-24-2012
MedicalExaminer's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 824
Threads: 66
Thanked 463 Times in 298 Posts
Reputation: 473
Default

I guess C
2 daughters
__________________
Everything is possible for him who believes (MARK 9:23)
245/247/passed on 1st attempt/223/2mos Obsie /3 US LORS/visa not needed/2008 grad
Reply With Quote Quick reply to this message
  #3  
Old 12-24-2012
dr.Irina's Avatar
USMLE Forums Veteran
 
Steps History: 1 + CK
Posts: 229
Threads: 6
Thanked 69 Times in 61 Posts
Reputation: 79
Default

Flagile X s-m
i am with c )
Reply With Quote Quick reply to this message
 
  #4  
Old 12-24-2012
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 106
Threads: 35
Thanked 17 Times in 10 Posts
Reputation: 27
Default

Quote:
Originally Posted by MedicalExaminer View Post
I guess C
2 daughters
Yes , its C . How do u get it?
Thank
Reply With Quote Quick reply to this message
  #5  
Old 12-24-2012
MedicalExaminer's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 824
Threads: 66
Thanked 463 Times in 298 Posts
Reputation: 473
Default

Mom is carrier (Xx)
Father is healthy (XY)

There is chance of 50 % of sons being diseased (XY 50% xY 50%) and 50% of daughters being carriers
(XX 50% xX 50%) so there are 4 daughters and the probability being carriers is 50% = 2
__________________
Everything is possible for him who believes (MARK 9:23)
245/247/passed on 1st attempt/223/2mos Obsie /3 US LORS/visa not needed/2008 grad
Reply With Quote Quick reply to this message
The above post was thanked by:
medhelp (12-24-2012)
  #6  
Old 12-24-2012
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 106
Threads: 35
Thanked 17 Times in 10 Posts
Reputation: 27
Default

Quote:
Originally Posted by MedicalExaminer View Post
Mom is carrier (Xx)
Father is healthy (XY)

There is chance of 50 % of sons being diseased (XY 50% xY 50%) and 50% of daughters being carriers
(XX 50% xX 50%) so there are 4 daughters and the probability being carriers is 50% = 2
Thanks I missed the point about mother being a carrier
Reply With Quote Quick reply to this message



Reply

Tags
Genetics-, Step-1-Questions

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
Trinucleotide Repeats Diseases ashishkabir USMLE Step 1 Bits & Pieces 4 12-01-2016 11:20 PM
Will they know am a repeat applicant? ruijunsu IMG Residency Match Forum 2 10-07-2012 01:36 PM
question_ trinucleotide repeat mtoi USMLE Step 1 Forum 4 01-15-2011 01:14 PM
Can I ask the patient to repeat? Sevan USMLE Step 2 CS Forum 5 10-12-2009 11:03 AM

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)