Christina Applegate says she has been diagnosed with multiple sclerosis

• The actor Christina Applegate said she has multiple sclerosis.
• She tweeted that she was diagnosed a few months ago, and called it a "tough road."
• Multiple sclerosis disrupts communication between the brain and other parts of the body.

The actor Christina Applegate has shared that she has multiple sclerosis.

She tweeted early Tuesday: "Hi friends. A few months ago I was diagnosed with MS. It's been a strange journey. But I have been so supported by people that I know who also have this condition. It's been a tough road. But as we all know, the road keeps going. Unless some asshole blocks it."

The US National Institute of Neurological Disorders and Stroke describes multiple sclerosis as "an unpredictable disease of the central nervous system" that can "range from relatively benign to somewhat disabling to devastating, as communication between the brain and other parts of the body is disrupted."

"The vast majority of patients are mildly affected, but in the worst cases, MS can render a person unable to write, speak, or walk," it says. "MS is a disease with a natural tendency to remit spontaneously, for which there is no universally effective treatment."

Applegate is known for her TV and film roles such as "Married... with Children," and "Anchorman: The Legend of Ron Burgundy."

Most recently, she played a widower in Netflix's 2019 drama series "Dead to Me." She told The Hollywood Reporter at the time that she asked for her mastectomy to be written into the show.

Applegate was diagnosed with an early stage of breast cancer in 2008. She decided to undergo a double mastectomy after learning she had the BRCA1 gene, which can make it more likely to contract breast cancer.

"Her having a mastectomy was something I brought to [showrunner] Liz [Feldman] in the middle of filming. I was trying to figure out this core pain that she has, and I thought we never really see women in television or in film really being [shown] having had this surgery," Applegate told THR.

She went on to receive nominations for a Golden Globe, SAG award, and Critics' Choice award for the role.