MODY Probability Ratios in Patients Diagnosed with Type 2 Diabetes Mellitus at a Young Age

Maturity-onset diabetes of the young (MODY) is a non-rare group of monogenic inherited diabetes which is commonly confused with type 1 and type 2 diabetes. Due to high costs of genetic tests that provide a definitive diagnosis, some screening scales are used to identify the high-risk patients. In this study, we aimed to evaluate whether (MODY Probability Calculator [MPC]) which is one of the screening tests will be helpful in identifying our high-risk patients among young patients with type 2 diabetes.

The patients received the diagnosis of type 2 diabetes aged <35 years were included in the study. The anthropometric characteristics of the patients, the treatments they received at the time of diagnosis, and the current treatments were recorded by retrospectively scanning patient files.The patients with the diagnosis of type 1 diabetes having autoantibodies to the pancreas were excluded from the study. The probability of MODY was calculated using MPC..

The mean age of 72 patients (40% female) was 41.5±7.2 years. Eighteen of the patients (25%) were using insulin at the time of diagnosis. The mean HbA1c was 8.6±2.2% and C-peptide was 2.35±1.52 ng/ml. The mean MODY positive predictive score calculated by MPC for risk of MODY was 11.23 percent. There were 61 patients (84.7%) with a risk of ≤20%, 9 patients (12.5%) with a risk of 20-50%, and 2 patients (2.8%) with ≥50%. In the group with MODY PPV score >20%, the age of onset of diabetes and the body mass index was significantly lower than the others (p<0.05, for both). There was no significant difference between current treatments of both groups.

It has been reported that MODY risk calculated by MPC may yield different results in different populations. The results of this study showed that 15% of our young-onset diabetes patients had an MPC score above 20 percent. Requesting MODY genetic tests in this 15% of the patient group can be presented as a practical suggestion.