Maturity-onset diabetes of the young (MODY) is a heterogeneous group of diseases associated with gene mutations leading to dysfunction of pancreatic β-cells. Thirteen identified MODY variants differ from each other by the clinical course and treatment requirement. Currently, MODY subtypes 1–5 are best-studied, descriptions of the other forms are sporadic. This article reports a MODY12 clinical case, caused by a mutation in the gene of the ATP-binding cassette transporter sub-family C member 8 (ABCC8), encoding sulfonylurea receptor 1. Diabetes manifested in a 27-year-old non-obese man with epilepsy in anamnesis. No evidence of ketosis was present, pancreatic antibodies were undetectable, and C-peptide remained within the reference range. During the initial investigation, non-proliferative diabetic retinopathy and elevated albumin excretion rate was revealed. After 4 months, diabetes was complicated by pre-proliferative retinopathy and diabetic macular edema. Recurrent hypoglycemia and an increase in body weight was observed on moderate and even small insulin doses. Taking into account the clinical features and the presence of diabetes in four generations on the maternal side, screening for all MODY subtypes was performed. A mutation in the ABCC8 gene was found in proband and in his mother. After the insulin discontinuation, gliclazide modified release combined with sodium/glucose cotransporter 2 (SGLT2) inhibitors was started. This treatment eliminated hypoglycemia and improved glycemic variability parameters. A decrease in the amplitude of glucose excursions was documented by continuous glucose monitoring. After 3 months of treatment, glycemic control was still optimal, and no hypoglycemic episodes were observed. The case report demonstrates the clinical features of ABCC8-associated MODY and the therapeutic potential of a combination of sulfonylurea with SGLT2 inhibitor in this disease.

Maturity onset diabetes of the young (MODY) is a congenital form of diabetes characterized by onset at a young age and a primary defect in pancreatic-β-cell function. Currently, 14 subtypes of MODY are known, and each is associated with mutations in a specific gene: HNF4A, GCK, HNF1A, PDX1, HNF1B, NEUROD1, KLF11, CEL, PAX4, INS, BLK, KCNJ11, ABCC8, and APPL1. The most common subtypes of MODY are associated with mutations in the genes GCK, HNF1A, HNF4A, and HNF1B. Among them, up to 70% of cases are caused by mutations in GCK and HNF1A. Here, an analysis of 14 MODY genes was performed in 178 patients with a MODY phenotype in Western Siberia. Multiplex ligation-dependent probe amplification analysis of DNA samples from 50 randomly selected patients without detectable mutations did not reveal large rearrangements in the MODY genes. In 38 patients (37% males) among the 178 subjects, mutations were identified in HNF4A, GCK, HNF1A, and ABCC8. We identified novel potentially causative mutations p.Lys142*, Leu146Val, Ala173Glnfs*30, Val181Asp, Gly261Ala, IVS7 c.864 −1G>T, Cys371*, and Glu443Lys in GCK and Ser6Arg, IVS 2 c.526 +1 G>T, IVS3 c.713 +2 T>A, and Arg238Lys in HNF1A.

The APPL1 gene encodes a protein mediating the cross-talk between adiponectin and insulin signaling. Recently, it was found that APPL1 mutations can cause maturity onset diabetes of the young, type 14. Here, an analysis of APPL1 was performed in patients with a maturity-onset diabetes of the young (MODY) phenotype, and prevalence of these mutations was estimated in a Russian population, among type 2 diabetes mellitus (T2DM) and MODY patients. Whole-exome sequencing or targeted sequencing was performed on 151 probands with a MODY phenotype, with subsequent association analysis of one of identified variants, rs11544593, in a white population of Western Siberia (276 control subjects and 169 T2DM patients). Thirteen variants were found in APPL1, three of which (rs79282761, rs138485817, and rs11544593) are located in exons. There were no statistically significant differences in the frequencies of rs11544593 alleles and genotypes between T2DM patients and the general population. In the MODY group, AG rs11544593 genotype carriers were significantly more frequent (AG vs. AA + GG: odds ratio 1.83, confidence interval 1.15–2.90, p = 0.011) compared with the control group. An association of rs11544593 with blood glucose concentration was revealed in the MODY group. The genotyping data suggest that rs11544593 may contribute to carbohydrate metabolism disturbances.

Diabetes mellitus with autosomal dominant inheritance, i.e., maturity-onset diabetes of the young (MODY), is a genetic form of diabetes mellitus. The MODY phenotype is associated with gene mutations leading to pancreatic β-cell dysfunction. Here, we present the clinical case of a 50-year-old proband with familial diabetes mellitus in five generations (proband, her mother, grandmother, great-grandfather, and son). This disease is most likely associated with the novel Ser6Arg mutation in the HNF1A gene, which was identified in four family members. The mutation was not detected in MODY patients (126 subjects), in patients with type 2 diabetes mellitus (188 subjects), and in a general population sample (564 subjects).

To verify the type of diabetes mellitus (DM) remains an extremely important problem in endocrinology, as along with types 1 and 2 DM there are rarer hereditary types of DM, including maturity-onset diabetes of the young (MODY). The latter is a genetic type of DM, which is characterized by an autosomal dominant inheritance. Eleven types of MODY (MODY 1 to MODY13) are identified; each is associated with mutations in the certain gene: HNF4A, GCK, HNF1A, PDX1, HNF1B, NEUROD1, KLF11, CEL, PAX4, INS, BLK, KCNJ11 and ABCC8. A molecular genetic testing for suspected MODY is conducted to verify the diagnosis and to define a subtype of MODY, patient management tactics, to predict the outcome of the disease and its complications in relation to the found subtype of MODY. It is also important to seek mutation causing MODY in terms of the early detection of MODY in the first-degree relatives of a proband, appropriate therapy of the disease, and prevention of its complications.

Earlier, GLIS3 gene polymorphisms have been shown to be associated with the development of maturity onset diabetes of the young (MODY). We screened GLIS3 gene sequences among patients with MODY to identify probably pathogenic variants by whole-exome sequencing. We estimated frequency of rare single-nucleotide variants in the coding region of GLIS3 in a Caucasian population and among individuals with carbohydrate metabolism disorders in Russia. We identified 15 single-nucleotide variants in GLIS3. Three rare variants (minor allele frequency < 1%) rs806052, rs143051164, and rs149840771 were genotyped in 126 cases of MODY, in 188 patients with type 2 diabetes mellitus (DM2), and 564 randomly selected Caucasian individuals in Russia. A heterozygous rs806052 variant was identified in one patient with DM2; c.1270T frequency was 0.003. Prevalence of rs143051164 c.844G was 0.003 in the control population and 0.004 and 0.003 in MODY and DM2 samples, respectively. Prevalence of rs149840771 c.2096A was 0.003 and 0.004 in the control population and among MODY patients, respectively. In DM2 patients, rs149840771 c.2096A was not identified. We did not detect any associations of rs806052, rs143051164, and rs149840771 with carbohydrate metabolism disorders among patients with MODY and DM2 in Russia.