Identification of a novel MEFV L560F variant in a patient with Mollaret meningitis

Mollaret meningitis is a rare neurological condition characterized by recurrent episodes of aseptic meningitis and the presence of monocyte-derived atypical cells (Mollaret cells) in the cerebrospinal fluid. It is most frequently associated with herpes simplex virus type 2 infection; however, autoimmune and inflammatory disorders, including familial Mediterranean fever, have also been implicated in its pathogenesis. Here, we report an unreported MEFV variant in a patient with Mollaret meningitis and aim to evaluate its pathogenic relevance through in vitro functional analyses.

MEFV exon sequencing was performed in a patient with Mollaret meningitis who showed a favorable response to colchicine treatment. Functional analyses were conducted using THP-1 cell lines. THP-1 monocytes were transfected with the identified MEFV variant or a wild-type MEFV construct, and their effects on cell death and apoptosis-associated speck-like protein containing a Caspase Recruitment Domain (ASC) speck formation were evaluated, with or without UCN-01 stimulation.

MEFV exon sequencing revealed a novel heterozygous L560F variant (c.1678C > T). Functional analyses demonstrated that, compared with the wild-type MEFV, the L560F variant induced more pronounced cell death and ASC speck formation following UCN-01 stimulation, supporting the pathogenic role of this novel variant.

The L560F variant represents a novel MEFV variant with functional evidence supporting pathogenicity. The clinical effectiveness of colchicine in this patient further supports the pathogenicity of the L560F variant.