SOX1 and paraneoplastic neurologic syndrome: Early diagnosis of paraneoplastic neurological syndromes paves the way for prompt and efficient therapy.<h4>Case report</h4>we reported a 56-year-old man presenting with seizures and rapidly progressive cognitive impairment diagnosed as paraneoplastic limbic encephalitis (PLE) with anti-SRY-like high-mobility group box-1 (SOX-1) and anti-γ-aminobutyric acid B (GABAB) receptor antibodies and finally confirmed by biopsy as small cell lung cancer (SCLC).