Researchers at Seoul National University Hospital (SNUH) have discovered the cause of Chronic relapsing inflammatory optic neuropathy (CRION), the hospital said Monday.

Professors Lee Haeng-jin (left), Professor Kim Seong-joon and Professor Kim Sung-min

The team, led by Professors Lee Haeng-jin, Kim Seong-joon and Kim Sung-min at the hospital, revealed that myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) caused CRION.

Optic neuritis is an illness accompanied by a sudden drop in visual acuity, blurred vision, pain in the eyes and color vision impairment. The disease sometimes appears as an early symptom for patients with multiple sclerosis and optic neuromyelitis.

However, the medical sector has not been able to find the exact cause of CRION even in the absence of multiple sclerosis or optic neuromyelitis.

The team examined 615 patients with central nervous system inflammation who visited hospital from 2011 to 2017. As a result, 12 patients had CRION that recurred three to four times on average. Out of the 12 patients, 11 tested positive for MOG antibody, while one showed a borderline positive result.

“This study revealed the cause of CRION which was unknown until now,” Professor Kim Sung-min said. “With the results, we can now prevent patients with optic neuritis who have a specific MOG antibody from visual impairment through appropriate immunotherapy and early treatment.”

In the past, oral steroids or immunosuppressants were the main treatment options for optic neuritis due to MOG antibodies. Recently, this has changed to using plasma exchange, repetitive intravenous immunoglobulin injections, or monoclonal antibody preparations that remove B lymphocytes in the blood.

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