You are developing schizophrenia because your sibling has it is not really as high as you might think. So, don't be afraid. Schizophrenia refers to a mental disorder that affects one's ability to feel, think, and behave normally.
Though there has not been a particular cause discovered for schizophrenia, it is known to be associated with environment, genetics; and altered structure or chemistry of the brain can also have its effect in causing schizophrenia. Yeah, you might still be wondering, "but this disorder is associated with genetics."
When a family member of yours, such as your sibling or even parent, develops schizophrenia, there is only a ten percent (10%) possibility that you might develop it also. You can see it is not much. So, the chance is minimal, very minimal. This disorder may not really have a specific cure, though, but it can still be treated medically.