NBME 20

nbme20/Block 3/Question#1

The frequency of an autosomal recessive disease in ...

1/25

The frequency of an autosomal recessive disease in ...

1/25

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p + q = 1 p^2 + 2pq + q^2 = 1 if q^2 = 1/1600 = 0.00063 then q = sqrt(q^2) = 0.025 solve for p to get p = 1 - r = 1 - 0.025 = 0.975 the heterozygous carriers = 2pq = 1 - p^2 = 1 - 0.95 = 0.5 q^2 can be dropped b/c it's much smaller than p^2. The deletion is responsible for 80% of the mutations. 0.8 x 0.5 = 0.04 = 4/100 = 1/25

There might be an easier way to do this, but it worked for me.

submitted by jotajota94(9), 2019-05-25T18:02:17Z

Use the Hardy-Weinberg equation