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Anti-GAD65 Positive Stiff-Person Syndrome: Novel Association with Common Variable Immune Deficiency
Saturday, March 5, 2016
South Exhibit Hall H (Convention Center)
Jack G. Ghably, MD, Mark Guido, MD, Sara Atwater, MD, Guha Krishnaswamy, MD, FAAAI, CC-D, ABIHM
Rationale: Stiff-person syndrome (SPS) is a rare neurological disorder characterized by progressive muscle stiffness, rigidity, and painful spasms affecting the axial muscles eventually impairing ambulation. Majority (60%) of SPS patients are found to have autoantibody targeting glutamic acid decarboxylase (GAD), an enzyme involved in synthesis of GABA neurotransmitter. Some cases are idiopathic or neoplasm-related with no antibody detected.  In recent studies, serum containing high titer anti-GAD65 antibodies induced motor dysfunction in rats, suggesting antibody functionality.  SPS is known to be associated with various other autoimmune conditions (notably type 1 diabetes mellitus) but association with a primary immune deficiency disorder has not been described.

Methods: Here we report a case of a middle aged female patient with a history of common variable immunodeficiency well managed on subcutaneous immunoglobulin (SCIG) therapy who subsequently developed stiff-person syndrome. EMG findings were indicative of SPS and she tested positive for GAD65 antibodies.

Results: Her SPS symptoms responded to treatment with clonazepam and later levetiracetam. The patient was placed on higher doses of SCIG and her symptoms were greatly ameliorated and physical functionality restored.

Conclusions: More studies of neurological complications of PID and their management are essential.