While there are many clinical commonalities among multiple sclerosis (MS), neuromyelitis optical spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody disease (MOGAD), researchers now agree that the three autoimmune disorders are distinct and warrant different diagnostic criteria.
Jeffrey Bennett, MD, PhD, professor of ophthalmology and neurology at the University of Colorado School of Medicine, who was part of an international panel of pediatric and adult neurologists, neuro-immunologists, and researchers that published new diagnosis criteria for MOGAD last year, says that patients and researchers alike will benefit from the updated criteria.
“There has been a growing appreciation both on the clinical and research side that myelin oligodendrocyte glycoprotein (MOG-IgG)-related disease was distinct from other inflammatory diseases of the nervous system, particularly MS and NMOSD,” Bennett says. “It was important to distinguish those diseases from MOGAD because we were finding that about 40% of those who didn’t have the aquaporin-4 antibody associated with NMOSD were positive for the MOG-IgG antibody. This brought to light the question of whether MOGAD and NMOSD were overlapping conditions.”
Bennett presented on the new diagnostic criteria for MOGAD at the 2024 North American Neuro-Ophthalmology Society (NANOS) meeting this month, expressing the importance of distinguishing MOGAD from MS and NMOSD.
Defining the criteria for MOGAD
MOGAD has similar symptoms to MS and can sometimes be misdiagnosed as MS. However, it’s more common to have ocular symptoms with MOGAD.
About 20 million people worldwide have MOGAD, making it more than 15 times less common than MS.
“It’s an uncommon disease, but it shows up in about 5% of patients who walk through the door with optic neuritis at the Sue Anschutz-Rodgers Eye Center,” Bennett says. “It demands attention because of its risk for recurrence and its potential to permanently damage the optic nerves and nervous system.”
Patients may experience blurry vision in one or both eyes, loss of color vision, and eye pain due to spinal cord inflammation. They may also experience weakness, paralysis, bladder control problems, and shooting pain along the back, neck, and abdomen. Children with MOGAD may additionally experience acute disseminated encephalomyelitis (ADEM), which includes symptoms of weakness, loss of balance, change in vision, nausea and vomiting, and confusion.
Unlike MS and NMOSD, which are both more common in women than men, MOGAD seems to be equally common in both sexes, Bennett says. It also seems to be clear of any ethnic associations.
Foundation for new research and effective treatment
The new diagnostic criteria, which involves confirming through a blood test in addition to clinical presentation, is an important part of learning more about the conditions and finding effective treatments, which don’t currently exist for MOGAD.
“Trying to classify what criteria would definitively state that a person had MOGAD is important so that when clinical studies are done, we know that all of the subjects actually have the disease,” Bennett says. “We want to look at homogeneous populations of patients.”
Similarly in a clinical setting, a patient who is thought to have MS, but who actually has MOGAD, may not respond to treatment in the same way.
“Optimizing patient care is contingent on everyone speaking the same language when doctors are making diagnoses,” Bennett says. “And when we do research and search the medical databases, if MOGAD diagnostic codes don’t mean the same thing to whomever is applying them, you’ll get a mix of patients that do not truly have the same disease.”
April 23, 2024