Dr. Wendy Walsh: When American pop star Lady Gaga divulged to CNN's Larry King and his millions of viewers that she has "borderline lupus," I scratched my head. I watched my own mother battle the disease for most of her life until her death from breast cancer, and I myself have what's known as a positive ANA (antinuclear antibody test), meaning that I carry the gene.

So what about Gaga? Does she have lupus, or not? Is there even such a thing as "borderline lupus"? Well, the nature of lupus is such that it is darned hard to diagnose, and doctors depend on a battery of tests (combined with symptomology reports) to make a complete diagnosis. Gaga could have tested positive for some things and not others, which means that technically speaking, she does not have lupus.

The autoimmune disease "systemic lupus erythematosus" (yes, I could rattle that off by the age of 5) is called "lupus" for short. It affects 1.5 million Americans, and 90 percent of sufferers are female. People of African, Latin and Asian origins are more susceptible. Lupus causes the body's immune system to become hyperactive and attack normal, healthy tissue.

Symptoms are many and varied and mimic other diseases. My mother -- who had both the lupus skin disease and the systemic disorder -- loved to giggle over the fact that she always tested positive for syphilis.

The most common symptoms of lupus are:

* Extreme fatigue 
* Headaches
* Painful or swollen joints
* Fever
* Anemia (low numbers of red blood cells or hemoglobin, or low total blood volume)
* Swelling (edema) in feet, legs, hands and/or around the eyes
* Pain in the chest on deep breathing (pleurisy)
* Butterfly-shaped rash across cheeks and nose
* Sun- or light-sensitivity (photosensitivity)
* Hair loss
* Abnormal blood clotting
* Fingers turning white and/or blue when cold (Raynaud's phenomenon)
* Mouth or nose ulcers

One thing doctors do know is that lupus has a hereditary component, and Lady Gaga connects her "borderline lupus" with an aunt who suffered from the illness. In my opinion, Lady Gaga probably has experienced some of the symptoms (what touring rock star doesn't experience extreme fatigue, anemia and headaches?), and she may have a positive ANA like me. That means she carries the gene and has a predisposition to lupus, but does not have the full-blown disease. Let's hope it stays that way.

As for me ... well, let's see. Even with my own "borderline lupus," I have challenged my body during its 40-something years. I have run a triathlon, taught more aerobics classes than I can count, have borne two children and nursed them for a total of six years -- and my body is still full of life! May Lady Gaga be so fortunate.