UPDATED June 20: Jack Osbourne first realized something was wrong with his health when he experienced vision problems last month, People magazine reported.

Doctors told Osbourne that he had lost 80 percent of vision in his right eye because of multiple sclerosis, he told People, and now he has started eating a healthier diet and taking medications to ease symptoms of MS.

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Jack Osbourne, the son of Ozzy and Sharon Osbourne, has announced his diagnosis with the autoimmune disease multiple sclerosis.

The 26-year-old, whose fiance Lisa Stelly had just given birth to a new baby, was "angry and frustrated and kept thinking, 'Why now?'" People magazine reported.

According to HELLO! magazine, Jack was diagnosed with the neurological condition last month.

"I keep thinking: 'What did I do wrong? What did I eat or drink when I was pregnant? I feel like it's somehow my fault," Jack's mother, Sharon, told Hello!.

According to the National Institutes of Health, the onset of multiple sclerosis typically occurs between ages 20 and 40, and is more common in women than in men. Symptoms -- which include weakness of the muscles, strange numbing or prickling sensations, cognitive problems, coordination issues and disturbances in vision -- may start out mild, but can become severe enough to where a person is no longer able to speak or walk.

But because symptoms can come and go, or can be very mild, a diagnosis for multiple sclerosis is sometimes hard to come by, according to the National Institutes of Health.

The condition occurs when the myelin sheath -- which covers nerve cells -- is damaged by inflammation, causing impairment of nerve signals, according to the A.D.A.M. Medical Encyclopedia.

However, scientists aren't completely sure why this inflammation and damage occur. The Mayo Clinic reported that it might be caused by a combination of genetics or infection. Risk factors for the condition include being between ages 20 and 40, being a woman, being white, having a family history of the condition, having another autoimmune condition, living in a "temperate climate" country, or having the Epstein-Barr virus (which is responsible for infectious mononucleosis).

Even though there is no cure for multiple sclerosis, there are treatments for the symptoms of the condition, according to the Mayo Clinic. However, some people's symptoms are mild enough to where they don't need to take medication, which itself can bring on its own side effects, according to the National Institutes of Health.

In addition, regular exercise, getting rest, lowering stress, eating healthily and keeping cool (with cool baths) can help to relieve symptoms, according to the Mayo Clinic.

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