To determine the pattern of peripheral nervous system involvement in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).
Recent studies have reported peripheral neuropathies in patients harboring myelin oligodendrocyte glycoprotein (MOG) antibodies but often lacked testing of disease controls.
It was a retrospective cohort study carried out at Mayo Clinic (Minnesota, Florida, and Arizona). Patients consecutively tested for MOG-IgG1 (January 1, 2003, to June 30, 2021) were included. Healthy human controls’ spinal cord, root and dorsal root ganglion were examined for MOG expression. All MOG-IgG1 seropositive patients were divided into three groups a) MOGAD with PNS involvement b) MOGAD with an alternate etiology of PNS involvement c) MOG-IgG1 false positive cases with PNS involvement. Archived sera from well characterized neuropathy/neuronopathy patients (n=196) were also evaluated for MOG-IgG1.
From a total of 279 patients , 215 fulfilled the international MOGAD diagnostic criteria. 15 of them were found to have PNS involvement. Six (median titer 1:40 (range 1:20 -1:100)) out of 215 MOGAD patients had PNS involvement that occurred concurrently with CNS demyelinating episode. Polyradiculopathy (6/6) was the most common phenotype of PNS disease. MRI of all six patients showed enhancement of the cauda equina nerve roots. Nine (median titer 1:500 (range 1:20-1:1000)) patients with true positive MOG-IgG1 had PNS involvement that was temporally unrelated to a CNS demyelinating event. All these patients had an alternate etiology of PNS involvement. Additionally, five (median titer 1:20 ) out of 196 patients sera from well characterized neuropathy/neuronopathy with an alternative etiology tested positive for MOG-IgG1 (amyotrophic lateral sclerosis, n =3; small fiber neuropathy, n =1; distal acquired demyelinating sensory neuropathy, n =1).