Answer:
If you have a faulty gene, (a gene defect) then every cell in you body has it and possibly all or some of the sex cells you produce will have it too. There is noting really at the moment you can do about this (but gene therapy is a developing science).
If you know you have a gene defect, you will have been told this by a qualified medical practitioner (a doctor). You need to ask this doctor to refer you to an expert in the field relating to your condition so that you can be advised how best to live your life and so you know the risks associated with your condition to passing the problem on to your offspring.