ABSTRACT
BACKGROUND: Monogenic diabetes (MgD) accounts for 1-2% of all diabetes cases. In adults, MgD is difficult to distinguish from common diabetes causes. We assessed the diagnosis rate and genetic spectrum of MgD using next-generation sequencing in patients with late adolescence/adult-onset diabetes referred for a clinical suspicion of MgD. METHODS: This cross-sectional study was performed in 1564 probands recruited in 116 Endocrinology departments. Inclusion criteria were the absence of diabetes autoantibodies, and at least two of the three following criteria: an age ≤ 40 years and a body mass index (BMI) < 30 kg/m2 at diagnosis in the proband or in at least two relatives with diabetes, and a family history of diabetes in ≥ 2 generations. Seven genes (GCK, HNF1A, HNF4A, HNF1B, ABCC8, KCNJ11, and INS) were analyzed. Variant pathogenicity was assessed using current guidelines. RESULTS: Pathogenic variants were identified in 254 patients (16.2%) and in 23.2% of EuroCaucasian patients. Using more stringent selection criteria (family history of diabetes in ≥ 3 generations, age at diabetes ≤ 40 years and BMI < 30 kg/m2 in the proband, EuroCaucasian origin) increased the diagnosis rate to 43%, but with 70% of the identified cases being missed. GCK (44%), HNF1A (33%), and HNF4A (10%) accounted for the majority of the cases. HNF1B (6%), ABCC8/KCNJ11 (4.4%), and INS (2.8%) variants accounted for 13% of the cases. As compared to non-monogenic cases, a younger age, a lower BMI and the absence of diabetes symptoms at diagnosis, a EuroCaucasian origin, and a family history of diabetes in ≥ 3 generations were associated with MgD, but with wide phenotype overlaps between the two groups. In the total population, two clusters were identified, that mainly differed by the severity of diabetes at onset. MgDs were more prevalent in the milder phenotypic cluster. The phenotypes of the 59 patients (3.8%) with variants of uncertain significance were different from that of patients with pathogenic variants, but not from that of non-monogenic patients. CONCLUSION: Variants of HNF1B and the K-ATP channel genes were more frequently involved in MgD than previously reported. Phenotype overlapping makes the diagnosis of MgD difficult in adolescents/adults and underlies the benefit of NGS in clinically selected patients.
Subject(s)
Diabetes Mellitus, Type 2/diagnosis , Genetic Testing/methods , High-Throughput Nucleotide Sequencing/methods , Adolescent , Adult , Cross-Sectional Studies , Female , Humans , Male , Young AdultABSTRACT
Diagnostic circumstances and clinical forms of type 1 diabetes. In its classic form, type 1 diabetes is the prototype of insulindependent diabetes. But ketoacidosis can occur outside of type 1 diabetes, so ketoacdosis does not necessarily mean definitive insulin therapy. Conversely, type 1 diabetes may initially be mistaken for type 2 diabetes. This is often associated with insulin delay after months of wandering and poor blood glucose control. New forms of diabetes have appeared, such as fulminant diabetes, specific to individuals from South Asia and the Far East, but also iatrogenic forms associated with new immunomodulatory treatments that revolutionize the management of certain cancers. This review presents the clinic and differential diagnosis of type 1 diabetes including these new forms of diabetes.
Circonstances diagnostiques et formes cliniques du diabète de type 1. Dans sa forme classique, le diabète de type 1 est le prototype du diabète insulinodépendant. Mais l'acidocétose peut s'observer en dehors du diabète de type 1, elle ne signifie donc pas forcément insulinothérapie définitive. À l'inverse, le diabète de type 1 peut être pris initialement pour un diabète de type 2 ; cela est souvent associé à un retard à la mise à l'insuline après des mois d'errance et de mauvais contrôle des glycémies. De nouvelles formes de diabète sont apparues, comme le diabète fulminant, spécifique des individus originaires de l'Asie du Sud et de l'Extrême-Orient, mais aussi des formes iatrogènes associés aux nouveaux traitements immunomodulateurs qui révolutionnent la prise en charge de certains cancers. Ce texte présente le tableau clinique et le diagnostic différentiel du diabète de type 1 en incluant ces nouvelles formes de diabète.
