Vitamin D plays an important role in insulin secretion. There is also evidence that this steroid may influence the insulin sensitivity. Thus genes involved in its metabolic pathway have been regarded as good candidates for type 2 diabetes mellitus (T2DM). One of them is vitamin D receptor gene (VDR). Its multiple polymorphisms have been examined for the association with T2DM in several populations. Those studies did not provide clear answers about the role of VDR in this disease. The aim of the study was to search for the association of FokI, ApaI, BsmI, and TaqI polymorphisms of VDR gene with T2DM in a Polish population using a case-control study design. Overall, 548 individuals were examined: 308 T2DM patients and 240 control individuals. The study groups were genotyped for VDR FokI, ApaI, BsmI, and TaqI variants using the restriction fragment length polymorphism (RFLP) method. Since variants of ApaI, BsmI, and TaqI polymorphisms were in very strong linkage disequilibrium, three loci haplotypes could be assigned to phase-unknown individuals with a high degree of confidence. Differences in allele, genotype, haplotype, and haplotype combination distribution between the groups were examined by chi2 test. The VDR allele frequencies for T2DM patients and controls were as follows: FokI-F/f - 53.4 %/46.6 % vs. 55.2 %/44.8 %, BsmI-B/b - 34.4 %/65.6 % vs. 37.5 %/62.5 %, ApaI-A/a - 47.9 %/52.1 % vs 50.9 %/49.1 %, TaqI-T/t - 67.6 %/32.4 % vs. 62.7 %/37.3 %, respectively. There was no difference between the groups in allele frequency. Similarly, distribution of genotypes, three locus BsmI/ApaI/TaqI haplotypes and their combinations were similar in the groups. In conclusion, our study did not provide evidence for the association of four examined VDR polymorphisms with T2DM in a Polish population. We postulate that to fully determine whether the sequence differences in VDR gene are susceptibility variants for T2DM, additional studies in different populations are required in a large study group.

In summary, the switch from insulin therapy to SU treatment in PNDM related to KCNJ11 mutations was found to be an efficient and safe therapeutic method over a period of 34-month median follow-up. Although no serious side effects were associated with SU treatment, their use in Kir6.2 PNDM requires further attention, particularly in children, adolescents, and patients with advanced chronic diabetes complications.

Macrosomia risk remains high in type 1 diabetes (T1DM) complicated pregnancies. A linear relationship between macrosomia risk and glycated hemoglobin A1c (HbA1c) was described; however, low range of HbA1c has not been studied. We aimed to identify risk factors and examine the impact of HbA1c on the occurrence of macrosomia in newborns of T1DM women from a cohort with good glycemic control. In this observational retrospective one-center study we analyzed records of 510 consecutive T1DM pregnancies (1998–2012). The analyzed group consisted of 375 term singleton pregnancies. We used multiple regression models to examine the impact of HbA1c and self-monitored glucose in each trimester on the risk of macrosomia and birth weight. The median age of T1DM women was 28 years, median T1DM duration—11 years, median pregestational BMI—23.3 kg/m2. Median birth weight reached 3520 g (1st and 3rd quartiles 3150 and 3960, respectively) at median 39 weeks of gestation. There were 85 (22.7 %) macrosomic (>4000 g) newborns. Median HbA1c levels in the 1st, 2nd, and 3rd trimester were 6.4, 5.7, and 5.6 %. Third trimester HbA1c, mean fasting self-monitored glucose and maternal age were independent predictors of birth weight and macrosomia. There was a linear relationship between 3rd trimester HbA1c and macrosomia risk in HbA1c range from 4.5 to 7.0 %. Macrosomia in children of T1DM mothers was common despite excellent metabolic control. Glycemia during the 3rd trimester was predominantly responsible for this condition.

Sulfonylureas (SUs) were proven to be more effective than insulin in most Kir6.2 permanent neonatal diabetes mellitus (PNDM) patients. We report SU use during pregnancy in PNDM. A woman with the R201H Kir6.2 mutation became pregnant at the age of 37. The patient had been on glipizide 30 mg for 3 yr; her glycosylated hemoglobin level was 5.8%. She was diagnosed with chronic diabetes complications and a congenital defect of the urogenitary tract-a bicornuate uterus with septum. Because the effect of SU on fetal development is uncertain, she was switched to insulin after the pregnancy diagnosis; however, the subsequent glycemic control was unsatisfactory, with episodes of hyper- and hypoglycemia. Thus, in the second trimester, the patient was transferred to SU (glibenclamide, 40 mg), which resulted in stabilization of glycemic control; glycosylated hemoglobin in the third trimester was 5.8%. Prenatal genetic testing excluded the Kir6.2 R201H mutation in the fetus. A preterm cesarean delivery was carried out in the 35th week. The Apgar score of the newborn boy (weight, 3010 g; 75th percentile) was 8 at 1 min. He presented with hypoglycemia, transient tachypnea of the newborn, and hyperbilirubinemia. The recovery was uneventful. No birth defects were recorded. His development at the ninth month of life was normal. In summary, we show a high-risk pregnancy in long-term PNDM that despite perinatal complications ended with the birth of a healthy child. SUs, which seem to constitute an alternative to insulin during pregnancy in Kir6.2-related PNDM, were used during the conception period and most of the second and third trimesters.

DPP-IV inhibitors may be an effective tool of combined therapy in HNF1A MODY, and they seem to improve beta-cell function under fasting conditions.