NBME F6 S2 cystic fibrosis

Prep for USMLE Forum

» Log in | Register

Forum

Step 1

Match

Prep4USMLE Forum » USMLE Step 1 Forum » Genetics Forum

NBME F6 S2 cystic fibrosis

Author

5 Posts

clar697
Forum Guru
avatar

Topics: 190
Posts: 199

07/17/08 - 08:44 AM

A 2-year-old girl presents with symptoms indicative of cystic fibrosis. A sweat chloride test confirms the diagnosis. If the incidence of this genetic disease is 1/2500 among whites, which of the following is the approximate carrier frequency of this mendelian trait in this population?

A) 1/12
B) 1/25
C) 1/50
D) 1/125
E) 1/625

hitesh
.

Topics: 64
Posts: 1,084

07/17/08 - 10:00 AM

B) 1/25

P2 + Q2 + 2pq = 1 .... q2 = 1/2500. Therefore, q = 1/50 .. carrier frequency = 2pq.. Since, P= 1 (approx.. it's actually 49/50)... Carrier frequency = 2q = 2 X 1/50 = 1/25

___________________
13/30

Karime
Forum Guru
avatar

Topics: 16
Posts: 1,270

07/18/08 - 06:39 PM

___________________
Eterea ……..“Hoc in loco mors succurrere vivis gaudet”……("In this place death comes joyfully to the aid of the living" )

usmlekiller
Forum Guru
avatar

Topics: 18
Posts: 1,010

08/07/08 - 10:23 AM

___________________
FUTURE 99ER

vaibhavbora
Forum Elite
avatar

Topics: 20
Posts: 387

11/29/08 - 11:27 AM

1/25

___________________
VB

You don't have permission to post.