This all boils down to how one defines "disease".
Sometimes I get in a bad mood. That could be a disease. Sometimes I am hungry. I have a "food imbalance". It was inherited. When my mothers stomach was empty, she had a food imbalance too. The same thing happens to me. Ergo, I inherited "the gene".
It's really just as simple as to what level you define somethign as a disease.
You should attend one of my family's reunions. Out of my parents 60-odd direct descendants, there are about 25% of us in recovery. Plus a couple more I'm keeping a meeting chair warm for...