What are the chances of a person with this disease passing the disease to their offspring (include possible scenarios)?

A child with infantile or juvenile Tay Sachs Disease does not normally pass it on because they die between the ages of two and ten.  Adults with late onset Tay Sachs could potentially pass it onto their children because they die between the ages of twenty and thirty.  If the person with Tay Sachs Disease had a child with someone who also had it, the child would be guaranteed to have some form of the disease as well (see punnett square 1).  If the person with Tay Sachs had a child with a carrier, there is a 50% chance that the child will have the disease and a 50% chance that the child will be a carrier (see punnett square 2).  If the person with Tay Sachs had a child with a normal person, the child would be guaranteed to be a carrier (see punnett square 3).
Punnett square 1        

	t	t
t	tt	tt
t	tt	tt

 Punnett square 2

	t	t
T	Tt	Tt
t	tt	tt

Punnett square 3

	t	t
T	Tt	Tt
T	Tt	Tt

All punnett squares made by me

http://www.genetics.edu.au/pdf/factsheets/fs35.pdf

http://www.ntsad.org/index.php/tay-sachs