MOGAD: what to know about MOG antibody disease

What MOGAD is

MOG stands for myelin oligodendrocyte glycoprotein. It sits on the surface of myelin, the coating that protects nerve fibers in the central nervous system, including the optic nerves. In MOGAD, the immune system makes antibodies against MOG. Those antibodies lead to swelling and damage to myelin, which disrupts nerve signals.

MOGAD is a fairly new name. An international panel of experts proposed formal criteria for it in 2023. Before that, some people with MOGAD were first told they had NMOSD, transverse myelitis, ADEM, optic neuritis, or MS. A new name on a chart often means the team understands the illness better, not that a new illness has appeared.

MOGAD and AQP4-positive NMOSD can look alike, but experts think they work through different immune paths. People with MOGAD also seem less likely to have other autoimmune diseases, such as thyroid disease or rheumatoid arthritis.

MOGAD can be one attack, called monophasic, or come back over time, called relapsing.

Sources: Cleveland Clinic: MOGAD; SRNA: MOGAD fact sheet; Lancet Neurology: International MOGAD Panel criteria.

MOGAD symptoms

MOGAD symptoms depend on where the attack happens. The optic nerve is the most common target, but the spinal cord and brain can be hit too.

Age shapes the pattern. In children, MOGAD most often affects the brain as ADEM, sometimes with optic neuritis. In adults, it more often affects the optic nerves and spinal cord.

The useful detail is what changed from the person's usual self. A parent may notice a child can't keep up on the stairs or is hard to wake. An adult may notice that reading has become hard through one eye.

Get urgent care for sudden vision loss, new weakness, trouble passing urine, a first seizure, or a drop in alertness. Don't wait for a routine antibody appointment.

Sources: SRNA: MOGAD fact sheet; Cleveland Clinic: MOGAD; AAO: optic neuritis.

What causes MOGAD

The cause of MOGAD is unknown. It isn't inherited, and no gene has been tied to it. Experts still don't know what makes the body start producing MOG antibodies.

Some attacks follow an infection. ADEM, the most common form of MOGAD in children, often follows a viral or bacterial illness. That timing doesn't prove the infection caused the disease. Many people have no clear event before an attack.

There is no known way to prevent MOGAD. Race and ethnicity don't seem to affect who gets it. Most adults are diagnosed in their 20s or 30s, and children are usually diagnosed before age 11. Still, it can start at any age.

Families sometimes look back for something they could have stopped. The evidence doesn't point to one.

Sources: Cleveland Clinic: MOGAD; NINDS: encephalitis; SRNA: MOGAD fact sheet; J Neurol: MOGAD review.

How MOGAD is diagnosed

Doctors diagnose MOGAD when three things line up. There must be an attack that fits, such as optic neuritis or myelitis. A blood test must find MOG antibodies on a cell-based test. And other diagnoses, especially MS, must be ruled out.

Only cell-based tests are considered reliable for MOG antibodies. Older test types gave more false results. Timing matters too. MOG antibodies can fade over time, and may not show up early or between attacks. Results can depend on timing and on treatment already given, so tell the team what has been given and when. Never delay urgent care to get a test.

A positive result isn't proof on its own. False positives happen, mostly at low levels and in people whose symptoms don't fit. A low positive result needs extra support from the exam or MRI, and the test may be repeated.

Other tests help. An MRI shows where inflammation is. In MOGAD, optic neuritis often affects both eyes and the front of the nerve, with a swollen optic disc. Spinal fluid may show more white blood cells. Oligoclonal bands, found in about 85 percent of people with MS, turn up in no more than about 20 percent of people with MOGAD.

Sources: SRNA: MOGAD fact sheet; J Neurol: MOGAD review; Lancet Neurology: International MOGAD Panel criteria.

MOGAD vs MS vs NMOSD

These three diseases can cause similar attacks, which is why careful testing matters. But they have different immune targets, patterns, and outlooks.

Use the table as a starting point, not a way to score a diagnosis. Early results don't always fit one column. In rare cases, a person tests positive for both MOG and AQP4 antibodies. Their course then tends to follow AQP4-positive NMOSD.

The difference matters because these diseases are not managed as one. A plan from an MS forum can't be moved over to MOGAD. Read more about how MS is diagnosed and about neuromyelitis optica.

Sources: SRNA: MOGAD fact sheet; NINDS: NMOSD; NINDS: multiple sclerosis; J Neurol: MOGAD review.

Treatment and outlook

There is no cure for MOGAD yet, and formal treatment guidelines haven't been set. For a new attack, specialists may consider steroids through a vein, plasma exchange, or immunoglobulin (IVIG).

Long-term treatment is a separate question. Because up to half of people have only one attack, specialists often save long-term immune treatment for those who relapse. Options they may consider include mycophenolate mofetil, rituximab, azathioprine, or repeated immunoglobulin. Most carry risks, such as infection. The specialist weighs those risks for each person.

The outlook varies from person to person. Disability after attacks is usually less severe than in NMOSD, and recovery is often better. Some people are left with lasting vision changes. Those whose first attack is in the spinal cord may have a higher chance of long-term disability. In people who relapse, later attacks tend to be milder. Lasting effects are still common. In a UK study of 75 people followed for a median of 28 months, 47 percent had at least one lasting problem, most often with bladder or bowel control rather than vision or walking.

Recovery is about daily life, not just exam scores. Rehab can help with daily tasks and getting around when vision or walking is affected. Our guides to optic neuritis and transverse myelitis explain those attack types in more depth. Children's care is covered in pediatric neuroimmunology.

Sources: Cleveland Clinic: MOGAD; SRNA: MOGAD fact sheet; Brain: MOG antibody disease prognosis in the UK.

Who this page is for

If you or your child may have MOGAD, we wrote this with you in mind. It should also help anyone whose old MS or NMOSD diagnosis is under review. It covers the disease, not a care plan for one person. Keep your test reports, and keep asking until the answers make sense.