CEREBELLAR ATAXIA ASSOCIATED WITH ANTI-GLUTAMIC ACID DECARBOXYLASE ANTIBODIES: A CASE REPORT

Abstract

INTRODUCTION
Anti-glutamic acid decarboxylase (anti-GAD) - related cerebellar ataxia is the second most common cause of GAD antibody (Ab) spectrum disorders. It is characterised by cerebellar symptoms with elevated GAD Ab levels in the serum and cerebrospinal fluid (CSF). It commonly affects females associated with Type 1 DM or polyendocrinopathy. IVIG is the most effective immunomodulatory therapy.

CASE
We report a 34-year-old male diagnosed with Type1 DM with high titer of serum anti-GAD Ab who first presented with cerebellar syndrome at the age of 12. At 15 years of age, Hba1c was 12% hence, insulin treatment was initiated. Initial diagnosis of neurodegenerative disorder was made in view of brain MRI findings showing cerebellar atrophy and family history of consanguineous marriage.

Laboratory investigation revealed high serum anti-GAD Ab titre >250 IU/ml. He was on basal-bolus insulin regimen and self-monitoring of blood glucose showed good control. There was no target organ damage. Furthermore, there was no progressive worsening of the neurological deficit. Repeated cranial MRI showed stable symmetrical hyperintensity in the atrophic middle cerebellar peduncles and pons with cerebellar atrophy. A lumbar puncture was performed and CSF analysis for anti-GAD Ab revealed remarkably high titre >250 IU/ml. Work-up for other causes of cerebellar ataxia and neurodegenerative disorders were negative. Immunomodulatory treatment was not initiated in view of non-progressive symptoms.

CONCLUSION
The unique association of autoantibody-mediated cerebellar ataxia and T1DM in this male patient is interestingly rare with childhood cerebellar syndrome as initial presentation before the diagnosis of Type 1 DM. Immunomodulatory treatment may be effective. We emphasize the importance of long-term follow-up, given the possibility of late development of other anti-GAD related neurological disorders and autoimmune polyendocrinopathy.