Clinical Heterogeneity in Patients with Glutamate Decarboxylase Antibody

Objective: To explore the diversity and clinical features of anti-glutamate decarboxylase (GAD) antibody-associated neurological diseases. Methods: Clinical data of a series of 5 patients positive for anti-GAD antibodies were retrospectively analyzed. Results: All 5 patients were female, with a median age of 41.5 years (range 19–60 years). Their neurological symptoms included stiff-person syndrome (SPS), encephalitis, myelitis, cramp, visual loss, and paresthesia. Three patients (60%) were diagnosed with tumors, 2 cases of thymic tumor and 1 of breast cancer. On immunohistochemistry for tumor pathology, expression of GAD65 was found only in 1 patient. Four patients (80%) had abnormal brain MRI findings. All patients received immunotherapy and improved significantly after treatment, but 4 (80%) then experienced a relapse. Conclusions: Neurological manifestations in anti-GAD-positive patients are diverse and include SPS, encephalitis, myelitis, cramp, visual loss, and paresthesia.