Unfortunately, this is very difficult to do, because in addition to the mutation that is causing the disease, your partner has hundreds of other mutations that

Unfortunately, this is very difficult to do, because in addition to the mutation that is causing the disease, your partner has hundreds of other mutations that are just part of the normal background. Based on my understanding of cases where the genetic basis of a rare disease is discovered, the best thing you can do is to find a physician who has studied others with a similar pathology. It's hard to learn much from one patient, but as soon as you have a few more, things can progress much more rapidly. The tricky part is finding that physician. There are some medical centers that specialize in rare genetic diseases; you might start there.