Jack Osbourne diagnosed with multiple sclerosis

Jack Osbourne, son of rocker Ozzy Osbourne and Sharon Osbourne, has been diagnosed with multiple sclerosis, he tells People.

"I was just angry and frustrated and kept thinking, 'Why now?' I've got a family and that's what's supposed to be the most important thing," says Osbourne. He is referring to the birth of his first child, daughter Pearl Clementine, born to Jack and his fiancee Lisa Stelly at the end of April.

Multiple sclerosis is a degenerative nerve disorder. The name refers to the schleroses, which are lesions, that appear on the white matter of the brain and spinal cord. The lesions eventually cause problems with muscle control, vision, balance, feeling and cognitive ability. It is not a fatal disorder, however. And the progression can range from just minor problems to major disabilities - it depends on each individual case.