Which of these genetic disorder usually does not express symptoms until adulthood?

Huntington's disease
Tay- Sachs disease
Sickle- cell disease
phenylketonuria
Kidney cysts

The answer is Huntington's. Tay-Sachs is expressed shortly after birth and individuals usually die by age 1. Sickle Cell appears young. I'm not surely when the earliest symptoms are, but I would think within a few years. PKU is expressed within a few months, but babies are tested immediately after birth to start child on proper diet to avoid mental retardation. In PKU, one amino acid can not change into another like it is supposed to do, eventually causing mental retardation. Kidney Cysts are not a genetic disorder.

Huntington's corea comes on around 30.

Not sure ,but i'd guess kidney cysts,not sure what the rest of them are.

Huntington's disease
Tay- Sachs disease
Sickle- cell disease
phenylketonuria
Kidney cysts

i think they all do

I'm pretty sure the answer is Huntington's chorea which usually strikes between the ages of 35 and 55.