. Jack and Jill are thinking about starting a family and they come to you with a question about a rare recessive genetic disease called Alpers Syndrome. Alpers causes progressive neurodegeneration in infants and children and is usually lethal within the first 10 years of life. Jack's grandfather had a brother die of Alpers Syndrome, while Jill has no family history of the disease. If the frequency of heterozygotes for Alpers is 1 in 2000 in the general population, what is the chance that Jack and Jill will have a child with Alpers Syndrome? (Be sure to completely reduce your answer.)

The chance of  having a Child who is a Heterozygote  is 50% , The chance of having a child that will completely come down with Alpers syndrome is 0%

Explanation:

Jack  has a history of Alpers in his family

Jill has no history

lets assume Jack is a carrier : Ab ( because that is how he could have survived the first 10 lethal  years )

Jill : AA

Therefore the probability/chance of Jack and Jill having a child with Alpers ( carrier ) syndrome will be 50 % as shown below

AA * Ab = AA , Ab, AA, Ab

The child produced by Jack and Jill will only be a carrier of the syndrome and not completely affected by the syndrome