GAD antibody-associated neurological illness and its relationship to gluten sensitivity

Background - The high prevalence of gluten sensitivity in patients with stiff-person syndrome (SPS) lead us to investigate the relationship between gluten sensitivity and GAD-antibody-associated diseases. Methods - We used ELISA assays for anti-GAD and for serological markers of gluten sensitivity. Patients were recruited from clinics based at the Royal Hallamshire hospital, Sheffield, UK. Patients with gluten sensitivity were followed up after the introduction of a gluten-free diet and serological testing was repeated. Results - Six of seven (86%) patients with SPS were positive for anti-GAD, mean titre 109 U/ml; This compared with 9/90 (11%) patients with idiopathic sporadic ataxia, mean titre 32 U/ml, 16/40 (40%) patients with gluten ataxia, mean titre 25 U/ml, and 6/10 patients with type 1 diabetes only, mean titre 8 U/ml. None of 32 patients with celiac disease only, and of 40 patients with genetic ataxia were positive for anti-GAD. The titre of anti-GAD reduced following the introduction of a gluten-free diet in patients with SPS who had serological evidence of gluten sensitivity. The same was observed in patients with gluten ataxia and anti-GAD antibodies. This was also associated with clinical improvement. Conclusion - These findings suggest a link between gluten sensitivity and GAD antibody-associated diseases.