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Pokemon deficiency is a rare autosomal recessive disorder presenting in infancy. 1 in 250,000 people is affected. Heterozygous carrier are not affected and have a normal blood biochemistry.
The proband (IV,3) was diagnosed to have Pokemon deficiency at 6 months of age. Her newborn younger brother was also diagnosed with the same disease.
Pokemon Deficiency
1. What is the probability of her 15 year old brother (IV,2) being a carrier?
A) 1 in 2
B) 1 in 4
C) 2 in 3
D) 1 in 3
E) 0
2. What is the probability of her mother (III,4) being a carrier.
A) 1
B) 1 in 2
C) 1 in 250,000
D) 0
E) Not possible to calculate.
3. What is the probability of individual III,2 being a carrier?
A) 1 in 8
B) 1 in 16
C) 1 in 2
D) 1 in 4
E) 1 in 250 000
4. If the population were in Hardy-Weinberg equilibrium, what is the carrier frequency in the population?
A) 1 in 250 000
B) 1 in 250
C) 1 in 5000
D) 1 in 1000
E) 1 in 100
5. What is the probability of the offspring of individual III,2 have Pokemon deficiency, if there is no consanguinity?
A) 1 in 1000
B) 1 in 250 000
C) 1 in 4
D) 1 in 256
E) 1 in 16000
6. If individual III,2 and III,1 were to produce a male offspring. What is the probability of him being affected?
A) 1in 4
B) 1 in 64
C) 1in 16
D) 1 in 5000
E) 1 in 128
Written by CH LEE on 20/12/2008
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1. C. 2/3 chance. Since we know that Pokemon Deficiency present in infancy, therefore the 15 years old healthy boy is not affected.
2. A. Both parents of affected children are obligated carriers.
3. D. 1 in 4 Chance. III,3 is a obligated carrier, he would either have inherited the affected allele from his father or mother. Therefore II,3 would have a 1 in 2 chance of being a carrier. The siblings of II,3 would share the same chance of being a carrier.
If II,2 is a carrier, she would have 1 in 2 chance of passing down the affected allele.
The chance of III,2 being a carrier= 1/2 x 1/2
=1/4
4. D. Frequency of affected individual in the population is 1 in 250 000, q^2.
Carrier frequency=2q
See more explanation about Hardy-Weinberg equilibrium on this website.
http://www.uic.edu/classes/bms/bms655/lesson13.html
5. E. the chance of III,2 being a carrier is calculated in the previous question, 1/4. We have calculated the carrier frequency in the population 1/1000. Chances of 2 carrier producing an affected offspring is 1/4.
Therefore chances of III,2 having an affected offspring= 1/4×1/1000×1/4.
6. B. 1/64. In case of consanguinity, the risk of affected offspring is higher. Chance of III,1 being a carrier is similar to III,2, 1/4.
Chance of producing an affected offspring=
1/4×1/4×1/4
haha.. Pokemon? Watch too much Pokemon is the cause.. haha.. just kidding… I think I should not comment here.. Anyway, how’s life?? Not much updates from u recently.. .
I do not know i possess the required knowledge to analyse this or not but I would like to attempt 🙂
1.A
2.A
3.C
4.D
sorry.. couldn’t continue… too many math.. 😛
Clever questions bro 😄