Objective: A 71 years old Italian man presented progressive dysarthria and involuntary movements.

Background: Within two months he developed dysarthria, progressive homolateral oromandibular and arm dystonic posture, knee buckling and retropulsion. Movements were sudden, increased by action and sustained posture, lasting <5 seconds. Two years prior he was diagnosed with idiopathic CD4+ lymphocytopenia (ICL) and CMV infection. HIV and hematological/oncological disorders were excluded. The patient progressively developed parkinsonism and cognitive decline, with memory and visuospatial impairment. One year later, kidney tumor was suspected and after two months he died.

Methods: Brain MRI and EEG were performed and were unremarkable, whereas PET study showed significant hypermetabolic alterations in basal ganglia. Laboratory tests (blood ASLO, TSH, ANA, anti-phospholipid antibodies, ceruloplasmin and urinary copper) were normal. Positivity for HHV6, JCV e BK viruses was treated with no significant improvement. CSF showed oligoclonal bands (pattern type 4).

Results: Based of clinical manifestations, progression and imaging results, the diagnosis of faciobrachial dystonic seizures (FBDS) was formulated. Anti-VGKC and -LGI1 antibodies were negative, as well as anti-CASPR2, AMPA1/2, GABA-B1, NMDA, GQ1b, GAD, DPPX and Ho-Yu-Ri-Ma1/2-amphiphysin antibodies. Histoblot analysis with patient’s serum showed positive staining on rat brain sections, strengthening the hypothesis of autoimmune disorder. He was treated with IVIG and PEX with partial improvement.

Conclusions: Although ICL has been associated with autoimmune diseases in 14-23% of cases¹, this is the first report of autoimmune encephalopathy in this context. Moreover, our patient presented typical FBDS features, except for dysarthria and absence of hyponatremia, but classical anti-VGKC and anti-LGI1 antibodies were negative. LGI1-negative FBDS has been reported also in the context of insular seizures, characterized by prolonged dystonic episodes and hypersalivation². These reports support the hypothesis that FBDS associated with atypical features can be due to specific etiologies different from VGKC-complex antibodies. The identification of patient’s antibody target antigen(s) will be important to expand the spectrum of this progressive but curable condition, to shed light in the intricate landscape of autoimmune movement disorders, and to allow correlations between new antibodies and specific FBDS phenotypes.

References: 1.Brooks JP, Ghaffari G. Idiopathic CD4 lymphocytopenia. Allergy Asthma Proc. 2016 Nov;37(6):501-504

2.Patira R, Khatri V, Gutierrez C, Zubkov S. LGI1-negative faciobrachial dystonic-like seizures originating from the insula. Epilepsy Behav Case Rep. 2016 Jul 5;6:33

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MDS Abstracts - https://www.mdsabstracts.org/abstract/expanding-the-spectrum-of-faciobrachial-dystonic-seizures/