How is Tay-Sachs disease inherited?
Tay-Sachs disease affects children who inherit two copies of an altered gene from their carrier parents. Carriers of Tay-Sachs disease are not affected themselves, because they have a working gene as well as an altered one. Carrier parents have a one-in-four chance of having an affected child, a one-in-two chance of having a child who is an unaffected carrier and a one-in-four chance of having a child who doesn't carry any altered genes.