Simultaneous triple organ specific autoantibody profiling in adult patients with type 1 diabetes mellitus and their first-degree relatives

AIMS: We aimed to document prevalence and clinical presentations of seropositivities for glutamate decarboxylase (GAD)-antibody, celiac's disease (CD) and autoimmune thyroiditis (AIT) in adult patients with type 1 diabetes mellitus (T1DM), and their first-degree relatives. METHODS: Sixty-five patients with T1DM, 124 first-degree relatives and 65 healthy controls were screened for GAD-antibody, anti-thyroid peroxidase (ATPO), anti-thyroid stimulating hormone receptor (TSHR), anti-tissue transglutaminase and anti-gliadin antibodies in a matched case-control study. RESULTS: Prevalence of more than one seropositivity for CD-associated antibodies in T1DM-group is 6.0 times increased, compared with controls (p < 0.05). ATPO seropositivity is 5.3 times increased in T1DM group (p < 0.05), but TSHR antibody is comparable with controls (p > 0.05). Seropositivities for T1DM, AIT and CD are 4.3, 1.9 and 2.4 times more prevalent among first-degree relatives respectively, compared with controls (p < 0.05). Pathologically confirmed cases with CD among first-degree relatives were all identified at screening. In contrast, all of pathologically confirmed cases with CD in T1DM group, were either previously diagnosed or symptomatic at time of screening. In the group of patients with T1DM, 31% of seropositive cases for anti-ATPO were clinically latent for AIT, and 74% of ATPO (+) cases were identified at current screening study. Sixty-four per cent of ATPO (+) first-degree relatives were clinically latent for AIT, and 54% were identified at screening. CONCLUSION: Type 1 diabetes mellitus, CD and AIT represent a significant overlap in an adult population with already-diagnosed T1DM and their first-degree relatives. With regard to clinical presentations, CD was less likely to be clinically silent than AIT among patients with T1DM.