My sister has neurofibromatosis type 2. she only has the cafe spots on her body. will i develop it too? is there a chance she will get a tumor? :(

Neurofibromatosis: Are you certain your sister has NF2? What about NF1? The reason for asking is that cafe au lait spots are not used to diagnose NF2. What about your parents? Many cases are spontaneous, and you may never develop symptoms of NF. It depends on which type we are talking about and what other family members have it. Once you are sure of the diagnosis then your questions may be answered.

Depends on parent: NF2 inherited as change in the NF2 gene from one of parents. Some people have mutation with NF2 gene in first person in family to be affected. No matter if NF2 gene change was inherited from a parent or is newly affected, every person who has NF2 gene change has a 50% chance of passing on to children. If your parent does not have gene your sister was mutation and you are unlikely to have nf2.