Ann Romney was diagnosed with multiple sclerosis in 1998. When I interviewed her for Fox News at our Washington Bureau two weeks ago, she readily admitted to me how difficult the diagnosis was at first, leading to fear, uncertainty and dark times.

She characterized her recurrent symptoms as including profound fatigue (which she could readily distinguish as her “MS fatigue”), weakness, and problems thinking clearly. She acknowledged that stress plays a major role in her ability to cope with and respond to this difficult disease.

Like more than 400,000 other MS sufferers in the U.S. and 2.5 million around the world, Romney lives in anticipation of her next exacerbation, which can come at any time. In addition to fatigue, weakness, and affects on thinking, other characteristic symptoms for MS sufferers include visual loss, sensory loss, problems with balance, pain, and in up to one third of cases, wheelchair-necessitating paralysis.

MS is known medically as one of our “great imitators,” because it can mimic the symptoms of many other neurological diseases.

If you consider nerves to be like electrical wires, then MS is due to damage to the covering of the wires (myelin sheath), leading to abnormal conduction. It is now believed to be an autoimmune disease, meaning that the body’s own immune cells (B cells and T cells) are attacking this myelin lining of the nerves (white matter) in the brain and spinal cord. This explains why the disease response to forms of interferon (beta seron) which stabilize the cells (and their covering) and help to ward off autoimmune attack.

In addition, so-called targeted therapies, where a monoclonal antibody is employed to attack the immune cells directly before they can damage the white matter, have shown great promise.

Tysabri is commonly used and has shown a much greater response than standard treatment with beta seron, and a new targeted therapy, Lemtrada, has appeared to be very effective in clinical trials.

Both treatments have raised eyebrows however because of the potential for risky side effects – a brain inflammation known as PML in the case of Tysabri, and ITP (destruction of platelets) in the case of Lemtrada.

Still, it is clear that these targeted therapies along with stem cell are the wave of the near future in MS treatments. Romney has been very active in fundraising for MS research, including current efforts ongoing at Harvard.

More than that she has been a role model for how to respond strongly and courageously to chronic debilitating illness. In addition to MS she was diagnosed and treated for early breast cancer in 2008, yet continued to push on.

Through it all, she has continued to reach out to others, to show empathy and compassion for others in similar situations. As she told me that day in Washington, we all carry a “bag of rocks” on our back that renders us imperfect, and we have to accept each other and love each other in spite of and because of these imperfections.

Romney credits the support and love of her family and her husband in helping her overcome her illness. But she wouldn’t have made it this far without her own strength and endurance.

Marc Siegel MD is an associate professor of medicine and medical director of Doctor Radio at NYU Langone Medical Center. He is a member of the Fox News Medical A Team and the author of The Inner Pulse; Unlocking the Secret Code of Sickness and Health