Two rare cases of myelin oligodendrocyte glycoprotein antibody-associated disorder in children with leukodystrophy-like imaging findings

BACKGROUND: Children with acquired demyelinating syndromes (ADS) whose sera are positive for myelin oligodendrocyte glycoprotein (MOG) immunoglobulin (IgG) can be diagnosed with MOG-IgG associated disorder (MOGAD). Cases with leukodystrophy-like imaging findings with recurrent MOGAD have rarely been reported. CASE PRESENTATION: Two children with MOGAD, whose onset age was 6 months and 3 years, respectively, were admitted to the hospital due to fever and altered consciousness. In both children, MOG-IgG was detected in the serum using live cell-based assay. Brain magnetic resonance imaging (MRI) revealed leukodystrophy-like lesions with diffuse bilateral white matter. Cerebrospinal fluid (CSF) analysis showed mild pleocytosis with normal or slightly increased protein levels and no oligoclonal bands. Metabolic and inflammatory blood/CSF markers were all negative. Full exon gene testing revealed normal results, and nuclear and mitochondrial DNA were normal. Despite regular immunotherapy and reduction of lesions based on brain MRI results, the patients repeatedly relapsed and had residual neurological dysfunction at 3-4 years of follow-up. CONCLUSIONS: Although MOGAD is a monophasic and benign condition, certain MOGAD patients can experience multiple relapses and residual neurologic deficits. The spectrum of clinical manifestations in MOGAD is wider in children than in previously reported cases, including cases with leukodystrophy-like imaging findings. Such imaging findings along with MOG-IgG may occur recurrently and result in severe neurological prognosis. Patients with extensive and confluent white matter lesions should undergo early testing of MOG-IgG to ensure early therapy. In refractory cases, MOGAD treatment may need to be escalated beyond the current therapy, which means second-line immunotherapy should be performed as early as possible and hormone levels should not be rapidly reduced. Early diagnosis and appropriate treatment may improve the prognosis of children with MOGAD.