Clinical characteristics of 683 children and adolescents, aged 0-18 years, newly diagnosed with type 1 diabetes mellitus in Henan Province: a single-center study

Association of CIITA (rs8048002) and CLEC2D (rs2114870) gene variants and type 1 diabetes mellitus

Background

Type I diabetes mellitus (T1DM) is a significant health challenge, especially for children, owing to its chronic autoimmune nature. Although the exact etiology of T1DM remains elusive, the interplay of genetic predisposition, immune responses, and environmental factors are postulated. Genetic factors control immune reactivity against β-cells. Given the pivotal roles of CIITA and CLEC2D genes in modulating a variety of immune pathologies, we hypothesized that genetic variations in CIITA and CLEC2D genes may impact T1DM disease predisposition. This study was designed to explore the association between gene polymorphisms in CIITA (rs8048002) and CLEC2D (rs2114870) and type 1 diabetes (T1DM), with a focus on analyzing the functional consequence of those gene variants.

Methods

The study enlisted 178 healthy controls and 148 individuals with type 1 diabetes (T1DM) from Suez Canal University Hospital. Genotyping for CIITA and CLEC2D was done using allelic-discrimination polymerase chain reaction (PCR). Levels of glycated hemoglobin (HbA1c) and lipid profiles were determined through automated analyzer, while fasting blood glucose and insulin serum levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique. RegulomeDB was used to examine the regulatory functions of CIITA (rs8048002) and CLEC2D (rs2114870) gene variants.

Results

Analysis of the genotype distribution of the CIITA rs8048002 polymorphism revealed a significantly higher prevalence of the rare C allele in T1DM patients compared to the control group (OR = 1.77; P = 0.001). Both the CIITA rs8048002 heterozygote TC genotype (OR = 1.93; P = 0.005) and the rare homozygote CC genotype (OR = 3.62; P = 0.006) were significantly more frequent in children with T1DM when compared to the control group. Conversely, the rare A allele of CLEC2D rs2114870 was found to be significantly less frequent in T1DM children relative to the control group (OR = 0.58; P = 0.002). The heterozygote GA genotype (OR = 0.61; P = 0.033) and the rare homozygote AA genotype (OR = 0.25; P = 0.004) were also significantly less frequent in T1DM patients compared to the control group. Both CIITA (rs8048002) and CLEC2D (rs2114870) gene variants were predicted to have regulatory functions, indicated by a RegulomeDB score of (1f) for each.

Conclusion

The rare C allele of CIITA rs8048002 genetic variant was associated with an increased risk of developing T1DM, while the less common A allele of CLEC2D rs2114870 was associated with a reduced risk of T1DM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-024-01402-w.

Characterization of newly diagnosed type 1 diabetes in children and adolescents from 2017 to 2022 in China: a single-center analysis

OBJECTIVE

This study investigated the characteristics of newly diagnosed type 1 diabetes mellitus (T1DM) related to autoimmunity and the frequency of diabetic ketoacidosis (DKA) in children and adolescents from 2017-2022 in China.

RESEARCH DESIGN AND METHODS

Single-center regional data from the Department of Pediatric Endocrinology, Tongji Hospital, were used to compare 88 children and adolescents newly diagnosed with T1DM from 2020 to 2022 (i.e. during the COVID-19 pandemic in China) and 76 children and adolescents diagnosed with T1DM from 2017 to 2019. Auto-antibodies, including glutamic acid decarboxylase-65 and insulin auto-antibodies, were detected by enzyme-linked immunoassays. DKA was defined as a pH < 7.3 and/or a bicarbonate level < 15 mmol/L.

RESULTS

The median age of the 164 children and adolescents newly diagnosed with T1DM from 2017 to 2022 was 7.0 years (interquartile range [IQR]: 3.8-10.0 years; 51.83% male). The mean annual incidence of T1DM was 2.98 per 1,000,000 child years. The estimated frequency of auto-antibody positivity was 51.22% (n = 84), and there was no difference between the 2020-2022 group and 2017-2019 group (55.68% [n = 49] vs. 46.5% [n = 35]; p = 0.219). The frequency of DKA among the entire cohort was 57.93% (n = 95), and peaked in 2020 at 78.9% (15/19 patients). The frequency of DKA was not significantly higher in the 2020-2022 group compared with the 2017-2019 group (60.23% [n = 53] vs. 55.26% [n = 42]; p = 0.521). We found no significant difference in the frequency of DKA between patients who were negative vs. positive for auto-antibodies in the 2020-2022 group (64.10% [n = 25] vs. 57.14% [n = 28], p > 0.05). The C-peptide level and HbA1c (%) were positively correlated with onset age (R1 = 0.389, p < 0.01; R2 = 0.371, p < 0.01), and the estimated mean C-peptide level was 0.26 ng/ml (IQR: 0.2-0.4 ng/ml) in patients with DKA and 0.370 ng/ml (IQR: 0.2-0.6 ng/ml) in patients without DKA (p = 0.044).

CONCLUSIONS

This study showed the annual incidence of T1DM was 2.98 per 1,000,000 child years, gradually increased over the study period, and there was no significant increase in T1DM with auto-antibody positivity in children and adolescents newly diagnosed from 2020-2022 in China compared with the previous 3 years. Furthermore, the frequency of DKA was peaked in 2020, and were not significantly different between patients who were negative vs. positive for auto-antibodies.

SARS-CoV-2 Positive Serology and Islet Autoantibodies in Newly Diagnosed Pediatric Cases of Type 1 Diabetes Mellitus: A Single-Center Cohort Study

Acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, although presenting less severe forms of the disease in children, seems to play a role in the development of other conditions, including type 1 diabetes mellitus (T1DM). After the beginning of the pandemic, an increase in the number of T1DM pediatric patients was observed in several countries, thus leading to many questions about the complex relationship between SARS-CoV-2 infection and T1DM. Our study aimed to highlight possible correlations between SARS-CoV-2 serology and T1DM onset. Therefore, we performed an observational retrospective cohort study that included 158 children diagnosed with T1DM in the period April 2021-April 2022. The presence or absence of SARS-CoV-2 and T1DM-specific antibodies and other laboratory findings were assessed. In the group of patients with positive SARS-CoV-2 serology, a higher percentage had detectable IA-2A antibodies, more children were positive for all three islet autoantibodies determined (GADA, ICA, and IA-2A), and a higher mean HbA1c value was found. No difference existed between the two groups regarding DKA presence and severity. A lower C-peptide level was found in the patients presenting diabetic ketoacidosis (DKA) at T1DM onset. When compared to a group of patients diagnosed before the pandemic, an increased incidence of both DKA and severe DKA, as well as a higher age at diagnosis and higher levels of HbA1c were present in our study group. These findings have important implications for the ongoing monitoring and management of children with T1DM after the COVID-19 pandemic and highlight the need for further research to better understand the complex relationship between SARS-CoV-2 infection and T1DM.