NBME qn - missdoc99

[ArchivalUser]

Taysachs is AR with carrier frequency in individuals of ashkenazi jews descent is 1 in 30,on basis of carrier frequecy ,which of the following is best estimate of probability tht a child born to two parents ,both of whom are ashkenazi jewish descent ,will be affected by taysach`s disease


A 1in 15
B.1in 60
c.1 in 450
d 1 in 900
e 1in 1800
f 1 in 3600

[ArchivalUser]

probability of 2 carriers getting married - 1/30 times 1/30
praobability that dad will give the affected gene 1/2
probability that mom will give the affected gene 1/2
so the probability of having a child with tay sachs... 1/30 times 1/30 times 1/2 times 1/2
= 1/3600

[ArchivalUser]

agree w/ dr_aa answer is F

[ArchivalUser]

can we do like
1/30 times 1/30
as the chances of two carriers having an affected child is 1 in 4

so 1/30*1/30*1/4=1/3600

jus asking if this concept is rite

[ArchivalUser]

yup thats exactly how i did it

[ArchivalUser]

yup u can do it this way 2....

[ArchivalUser]

thanq

[ArchivalUser]

thanks