Now, what do I mean by that? And what are its consequences and what are the implications for health care? I will cite a number of examples to illustrate what I have in mind.
We’ll take the case of Rheumatoid Arthritis. For every many with Rheumatoid Arthritis, there are 2 to 3 women who are affected with this disorder. Now, is Rheumatoid Arthritis a disease of the reproductive tract? No. Is there any obvious anatomic difference between men and women to account for this dramatic difference in the incidence of Rheumatoid Arthritis, its higher incidence in women? There is no simple, anatomic explanation to be had.
Let’s flip the tables now and consider Autism Spectrum Disorders. For every girl with an Autism Spectrum Disorder the most recent numbers suggest that there are about 5 boys with such a disorder. Why is that the case? Let’s flip the table yet again. Lupus, a long term, autoimmune disorder with devastating consequences that can result in death, for every man who is suffering from Lupus, there are 6 women who are suffering from this disorder. And so, for a whole host of disorders that occur outside the reproductive tract we see that the incidence or prevalence in men and women can differ dramatically. And even in the case when a disease occurs in both men and women, that disorder can be much more severe or have more severe consequences in one sex than the other.
Let’s consider here the case of dilated cardiomyopathy. Dilated cardiomyopathy is a condition where the wall of the heart thins, and the heart balloons dangerously and sometimes, with devastating consequences.
What I’m going to show you here is the survival curve, the death curve, if you will, for women who have dilated cardiomyopathy due to a very specific genetic defect. It turns out that men can also get dilated cardiomyopathy as a result of this same specific genetic defect, but if they do, they tend to die at a much younger age. Why is this the case? Well, so I asked my colleagues. When I travel around, I ask my colleagues in biomedical research, why is it that for so many disorders, the incidence of disease or the severity of disease differs so dramatically between men and women? Why is this the case? And the answer that I almost invariably get is, “I don’t have a clue.”