MODY (Maturity Onset Diabetes of the Young) is a type of diabetes resulting from a pathogenic effect of gene mutations. Up to date, 13 MODY genes are known. Gene HNF1A is one of the most common causes of MODY diabetes (HNF1A-MODY; MODY3). This gene is polymorphic and more than 1200 pathogenic and non-pathogenic HNF1A variants were described in its UTRs, exons and introns. For HNF1A-MODY, not just gene but also phenotype heterogeneity is typical. Although there are some clinical instructions, HNF1A-MODY patients often do not meet every diagnostic criteria or they are still misdiagnosed as type 1 and type 2 diabetics. There is a constant effort to find suitable biomarkers to help with in distinguishing of MODY3 from Type 1 Diabetes (T1D) and Type 2 Diabetes (T2D). DNA sequencing is still necessary for unambiguous confirmation of clinical suspicion of MODY. NGS (Next Generation Sequencing) methods brought discoveries of multiple new gene variants and new instructions for their pathogenicity classification were required. The most actual problem is classification of variants with uncertain significance (VUS) which is a stumbling-block for clinical interpretation. Since MODY is a hereditary disease, DNA analysis of family members is helpful or even crucial. This review is updated summary about HNF1A-MODY genetics, pathophysiology, clinics functional studies and variant classification.

Several our previous studies showed associations of increasing blood level of persistent organochlorinated pollutants (POPs) with individual thyroid and metabolic adverse health signs in subjects from heavily polluted area (POLL) compared to these from the area of background pollution (BCGR). In this study we present increasing number of subjects with multiple adverse signs positively associated with blood level of polychlorinated biphenyls (PCBs) which is used as a marker of other POPs cocktail.

Recently, the genetic cause of several syndromic forms of glycemia dysregulation has been described. One of them, MEHMO syndrome, is a rare X-linked syndrome recently linked to the EIF2S3 gene mutations. MEHMO is characterized by Mental retardation, Epilepsy, Hypogonadism/hypogenitalism, Microcephaly, and Obesity. Moreover, patients with MEHMO had also diabetes and endocrine phenotype, but detailed information is missing. We aimed to provide more details on the endocrine phenotype in two previously reported male probands with MEHMO carrying a frame-shift mutation (I465fs) in the EIF2S3 gene. Both probands had a neonatal hypoglycemia, early onset insulin-dependent diabetes, and hypopituitarism due to dysregulation and gradual decline of peptide hormone secretion. Based on the clinical course in our two probands and also in previously published patients, neonatal hypoglycemia followed by early-onset diabetes and hypopituitarism may be a consistent part of the MEHMO phenotype.