Thanks for the insight. Here is the article we looked at previously which tries to also look at epidemiologic approaches to finding the genes causing illnesses. This article pointed out the fact that individuals with schizophrenia are more prone to several other illnesses and relatively protected from breast cancer and abdominal aortic aneurysm.
The article by Eric London pointed out the fact that studying strongly diametrically opposed illness propencities can lead to finding the genetic causes. They found that neurologic degenerative conditions like Alzheimers seem to protect against cancer (except melanoma) They found that patients with autoimmune disease seem to be protected against infectious illness. And they found that patients with osteoporosis seem protected against osteoarthritis.
These relationships are intrigueing since we find that osteoporosis (and vitamin D deficiency) are associated with schizophrenia and autism. We note the epidemiology of osteoporosis as cooccurring with that of N-related schizophrenia. And in our office patients, we saw a trend of osteoarthritis patients having NA type.