Facial Onset Sensory and Motor Neuronopathy

Abstract

Purpose of reviewTo improve our clinical understanding of facial onset sensory and motor neuronopathy (FOSMN).Recent findingsWe identified 29 new cases and 71 literature cases, resulting in a cohort of 100 patients with FOSMN. During follow-up, cognitive and behavioral changes became apparent in 8 patients, suggesting that changes within the spectrum of frontotemporal dementia (FTD) are a part of the natural history of FOSMN. Another new finding was chorea, seen in 6 cases. Despite reports of autoantibodies, there is no consistent evidence to suggest an autoimmune pathogenesis. Four of 6 autopsies had TAR DNA-binding protein (TDP) 43 pathology. Seven cases had genetic mutations associated with neurodegenerative diseases.SummaryFOSMN is a rare disease with a highly characteristic onset and pattern of disease progression involving initial sensory disturbances, followed by bulbar weakness with a cranial to caudal spread of pathology. Although not conclusive, the balance of evidence suggests that FOSMN is most likely to be a TDP-43 proteinopathy within the amyotrophic lateral sclerosis–FTD spectrum.

Facial-onset sensory and motor neuronopathy with myasthenia gravis: A case report

“…[2] One hundred cases of FOSMN syndrome have been reported to date. [3] FOSMN syndrome is typically characterized by the onset of facial paresthesia and sensory deficits in the facial trigeminal innervation area, with slow development along the rostral-caudal direction, affecting the scalp, neck, upper trunk, and upper limbs in a gradually progressive manner. [2][3][4][5] At the same time or later than the sensory symptoms, the cranial nerve and upper limb motor disorders also appear slowly, spreading in the same pattern as the sensory disorders.…”

“…[3] FOSMN syndrome is typically characterized by the onset of facial paresthesia and sensory deficits in the facial trigeminal innervation area, with slow development along the rostral-caudal direction, affecting the scalp, neck, upper trunk, and upper limbs in a gradually progressive manner. [2][3][4][5] At the same time or later than the sensory symptoms, the cranial nerve and upper limb motor disorders also appear slowly, spreading in the same pattern as the sensory disorders. Clinical symptoms and signs include asymmetric facial paralysis, masseter and temporal muscle weakness, dysarthria, dysphagia, tongue atrophy, and even dyspnea in a few patients, which may eventually lead to respiratory failure.…”

“…[2,7,8] The abovementioned pathological research evidence supports that FOSMN syndrome is a neurodegenerative disorder and a likely amyotrophic lateral sclerosis association with amyotrophic lateral sclerosis. [7][8][9][10] De Boer reviewed 100 FOSMN patients and discovered that Autoantibodies were positive in 14 of them, and that immunotherapy is partly effective in these patients, [3] however without any cases of anti-AchR antibody and anti-titin antibody. These discoveries indicate the probability of a potential immunological mechanism.…”

Taste loss as the sole presenting symptom in Chinese patient with facial onset sensory and motor neuronopathy

“…Only three reported patients have benefited, with only one having long-term effect and the other two patients having only transient improvement. 2,12 Considering the controversial therapeutic effects and the definite side effects of steroids, we did not use immunomodulatory therapies in our patients. It has been reported that the combined use of the ALS-targeted drug riluzole and the anti-inflammatory drug celecoxib presented neuroprotection in FUS-tg mice, which may imply the potential benefits in FOSMN.…”

TDP-43 proteinopathies: a new wave of neurodegenerative diseases

“…Heterozygous mutations in several fALS genes have been reported in FOSMN syndrome, including TARDBP , SOD1 , SQSTM1 , VCP and CHCHD10 , although the pathogenic significance of these remains to be determined. 73 Although the aetiology of FOSMN syndrome remains to be fully elucidated, the identification of TDP-43 positive intraneuronal inclusions suggests that FOSMN syndrome is a neurodegenerative disorder. 74–76 Importantly, some studies have failed to detect TDP-43 inclusions, 72 77 suggesting a heterogeneity of the disease process in FOSMN syndrome.…”