Endocrine Abstracts

Aim: To determine, in type 1 diabetes mellitus (T1DM) patients, if there is any relationship between the age at onset and the number of HLA risk alleles for T1DM (DRB1*03 and DRB1*04).

Methods: Retrospective study. We selected patients with T1DM diagnosis (pancreatic autoimmunity and insulin-dependent diabetes) and age at onset >15 years, identifying 275 subjects (59.6% men and 40.4% women), with a median age at onset of 31 years (interquartile range -IQR- 13 years). We registered the following data at the time of diagnosis: presence of ketoacidosis, glycemia, HbA1c, BMI, pancreatic autoantibodies GAD, IA2 and IAA (measured by radioimmunoassay with recombinant antigen) and HLA-DRB1 typing (determined by PCR-SSO). We compared the age at diagnosis between patients with 0, 1 or 2 HLA risk alleles. Also, we compared our sample’s HLA pattern with the one from a pediatric group (patients with onset before 15 years of age), obtained from a previous study from the same population and with identical diagnostic criteria (Urrutia I, et al. (2017) Lower Frequency of HLA-DRB1 Type 1 Diabetes Risk Alleles in Pediatric Patients with MODY. PLoS ONE 12(1): e0169389).

Results: 26.7% of patients had ketoacidosis at onset. Median glycemia at diagnosis was 359 mg/dL (IQR 150), being mean HbA1c 11.95% (SD 2.52) and median BMI 22.48 kg/m² (IQR 4,72). 91.6% of patients had positive anti-GAD antibodies, 39.0% anti-IA2 antibodies and 29.1% anti-IAA antibodies. Median age at onset (IQR) was 31 (15) years in patients without risk alleles; 32 (13) years in patients with 1 risk allele and 27 (12) years in patients with 2 risk alleles. Statistically significant difference and decreasing trend (Kruskal-Wallis P=0.037; Jonckheere-Terpstra P=0.046). The distribution of risk alleles between the 2 groups of age was as follows, with statistically significant differences (Pearson’s chi-squared test P=0.01).

Conclusions: In type 1 diabetes patients, the presence of two HLA-DRB1 risk alleles is associated with a disease onset at a younger age.