What is the gene that is responsible for developing schizophrenia.. if we suppose it's due to genetic factor?

Not just one gene: The genetics of inheriting a tendency toward schizophrenia seems to be variations or mutations not in just one gene location, but in one of many possible locations. So, we cannot blame just one particular gene mutation. With a genetically transmissible disorder, affected patients should think very carefully if planning to have children of their own.