Anti-glutamic acid decarboxylase antibodies-associated cerebellar ataxia: A treatable ataxia

Abstract

Anti-glutamate decarboxylase 65 antibody-associated cerebellar ataxia (anti-GAD65Ab-associated CA) is the most widely studied immune-mediated CA. There are few case series evaluating the clinical, radiological, treatment profile, and outcome of anti-GAD65Ab-associated CA. To study the clinical, radiological profile, associated neoplasm, treatment outcome, and prognosis in patients diagnosed with anti-GAD65Ab-associated CA. A retrospective descriptive analysis of a cohort of patients diagnosed with anti-GAD65Ab-associated CA was performed and analyzed. Thirteen patients were selected for the analysis with female predominance (70%). The mean age at presentation was 47.5 ± 11.1 years (range, 29–65 years), and the median duration of the symptoms was 4 months. All 13 patients (100%) had gait ataxia. Ten patients had limb ataxia along with gait ataxia (75%). Seven patients had cerebellar dysarthria (54%). Four patients (31%) had gaze-evoked jerky nystagmus. Five patients (39%) were diagnosed with type 2 diabetes mellitus, and one patient had hypothyroidism in addition to type 2 diabetes mellitus. Brain magnetic resonance imaging was normal in seven (54%) patients, and pure cerebellar atrophy was observed in six patients. One patient was detected with a colon neoplasm. All 13 patients received intravenous methylprednisolone, followed by oral steroids over 3 months. Six patients (50%) received plasma exchange along with intravenous methylprednisolone. Favorable outcomes (modified Rankin scale score ≤2) were observed in five patients and poor outcomes in two; six patients were lost to follow-up after the first admission. Anti-GAD65Ab-associated CA presents as subacute to chronic progressive CA with a favorable outcome with immunotherapy. Anti-GAD antibodies should be assessed in serum or cerebrospinal fluid in patients presenting subacute to chronic sporadic CA. The occurrence of a systemic neoplasm is rare in anti-GAD65Ab-associated CA.