Still struggling.

[Socratic Meth Head]

Again, so it is with dominant autosomal gene transmission. But if your parents aren't active carriers, it is less likely that you are an active carrier.

Huntington's disease is a good example. If one of a person's parents has Huntington's disease, they have a 50% chance of being an active carrier of the disease. If they aren't active carriers, then their kids (you in this instance) would have a 9.625% chance of carrying the disease, assuming the other parent is also not a carrier.

So, if your grandmother had it, and your mother doesn't have it, you are overwhelmingly unlikely to have it. No doctor would ever diagnose anyone with something that has this kind of expression without being sure. So if your parents say a doctor told them that you have this gene, and that doctor has never examined you for it or done the test (again, removing a strip of your hamstring), either they are seeing an extremely unethical doctor, or they have another motive.

They told my dad he has it, and my dad said it was likely that i have it. He was informed from the doctor, who found out from my grandmother. Its called Malignant Hyperthermia i think.