In a pedigree....which condition...?

_____31. In a pedigree, you notice that individuals who have a single parent with the condition have the condition themselves 50 percent of the time. Of the following, which condition has an inheritance pattern that best fits the description?


a) Tay-Sachs disease


b) Huntington's disease


c) Cystic fibrosis


d) Sickle-cell anemia


e) Phenylketonuria

In a pedigree....which condition...?
The answer is Huntington's Disease "a degenerative disease of the nervous system, is caused by a lethal dominant allele that has no obvious phenotypic effect until the individual is about 35-45 years old.....any child born to a parent who has the allele for Huntington's disease has a 50% chance of inheriting the allele and the disorder." (source: Campbell)
Reply:Each child of an HD parent has a 50-50 chance of inheriting the HD gene. If a child does not inherit the HD gene, he or she will not develop the disease and cannot pass it to subsequent generations.
Reply:I'm not completly sure but I'm pretty sure it's not sickle cell anemia since that is a blood disease that wouldn't really show up 50% of the time.
Reply:not my level..,
Reply:Huntingtons is a dominant condition. If you have a parent with the condition you have a 50% chance of getting it. I had a student whose mother and aunt both had it!! Poor boy.......


The others are recessive conditions.