Functionally defective germline variant of sialic acid acetylesterase (Met89Val) is not associated with type 1 diabetes mellitus and Graves' disease in a Polish population.

Recently, rare genotypes encoding defective variants of sialic acid acetylesterase (SIAE), such as homozygous Met89Val substitution, were strongly associated [odds ratio (OR) = 8] with a panel of autoimmune diseases including type 1 diabetes mellitus (T1DM). Our purpose was to replicate this finding in T1DM and explore whether Met89Val predisposes to Graves' diseases (GD). We studied 561 GD patients, 379 T1DM patients and 1822 controls. The prevalence of Met89Val homozygosity was similar among patients (GD: 0.4%, n = 2; T1DM: 0.3%, n = 1) and controls (0.4%, n = 7) yielding OR of 0.93 [95% confidence interval (CI): 0.19-4.48, P = 0.9] and 0.69 (95% CI: 0.08-5.59, P = 0.71) for GD and T1DM, respectively. We conclude that further studies are needed before the proposed strong effect of defective SIAE variants on susceptibility to autoimmunity can be universally accepted.