Frontotemporal Dementia with Parkinsonism and Epilepsy Associated with VGKC Antibodies: Case Report and Literature Review

We present the case of a 55-year-old man who initially presented with focal unaware seizures and behavioural changes mimicking anti-VGKC-seropositive encephalitis that further progressed to parkinsonism with evidence of frontotemporal dementia and pre-synaptic dopaminergic deficit. Aggressive treatment with immunotherapy was ineffective, and antibody subtyping later revealed the anti-VGKC antibodies to be negative for leucine-rich glioma-associated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) – the two known pathogenic subtypes. The clinical relevance of so-called “double-negative” anti-VGKCs (i.e., those not directed towards LGI1 or CASPR2) has been called into question in recent years, with evidence to suggest they may be clinically insignificant. Our case emphasises the importan ce of antibody subtyping in cases of anti-VGKC seropositivity; negative results, particularly when combined with a poor response to immunotherapy, should prompt a rapid reconsideration of the working diagnosis.Case Rep Neurol 2021;13:205 –210
Source: Case Reports in Neurology - Category: Neurology Source Type: research