ESPE Abstracts

Keywords: diabetes, MODY, atypical

Introduction: Type 1 Diabetes (T1D) is the most common cause of diabetes in childhood, but Type 2 Diabetes (T2D) and monogenic diabetes has attracted increasing attention recently. Cases with atypical diabetes may be challenging for diagnosis, treatment and follow-up management. The purpose of this study was to present the characteristics of atypical diabetes cases from a tertiary referral center.

Method: Diabetes cases <18 years old and diagnosed between 2000-2022 were evaluated. Those with Type1, Type2, neonatal and secondary diabetes were excluded. Those with extra-pancreatic findings and/or with measurable c-peptide levels three years after diagnosis, and patients with at least one of the diabetes-specific auto-antibodies (anti-GAD, islet cell antibody, anti-insulin antibody) being negative were included. The age at diagnosis, family history, and clinical and laboratory findings at diagnosis and during follow-up, and treatments were analyzed retrospectively.

Results: Of the 1237 diabetic patients, 1059 (85.7%) were Type1 and 99 (8%) were Type2. The remaining 79 (6.3%) constituted the study cohort, of whom genetic variants were detected in 38 (3%). Median diagnosis age in the 79 was 7 (3-15.6) years and 61% were female. The rate of consanguineous marriage was 8.1% although 58% had a history of diabetes in three generations, and this rate was 17% for two generations. Eight had gestational diabetes and 19 (24%) had a sibling with diabetes. A total of 28 (35%) patients were diagnosed incidentally. The median c-peptide level was 1.1 (0.1-5.6)ng/mL and HbA1c 8.6 (5.8-17.6)%. Diabetes antibody positivity was GAD n=11, anti-insulin n=8, and anti-islet n=3. MODY (HNF4A, KCNJ11, INS) was diagnosed in 3/4 patients presenting with ketoacidosis. Among the 79,42 (53.2%) were treated with multiple insulins, 7 (8.9%) with basal-acting insulin only, 10 (12.7%) with oral antidiabetics, and 20 (25.3%) with diet. MODY-associated variants were present in 21 (26.6%). Seventeen had other diabetes-related variants (Table 1).

Conclusion: Clinician experience is important in the diagnosis of cases that do not suggest Type 1DM. To diagnose rare autosomal recessive monogenic diabetes and to offer appropriate treatment options, specific algorithms are needed for populations with a high rate of consanguineous marriage, such as in Turkey.