Screening for monogenic subtypes of gestational diabetes in a high prevalence island population - A whole exome sequencing study.

AIMS: The reported frequency of monogenic defects of beta cell function in gestational diabetes (GDM) varies extensively. This study aimed to evaluate the frequency and molecular spectrum of variants in genes associated with monogenic/atypical diabetes in non-obese females of Maltese ethnicity with GDM. METHODS: 50 non-obese females who met the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criteria for diagnosis of GDM and with a first-degree relative with non-autoimmune diabetes were included in this study. Whole exome capture and high throughput sequencing was carried out. Rare sequence variants were filtered, annotated, and prioritised according to the American College for Medical Genetics guidelines. For selected missense variants we explored effects on protein stability and structure through in-silico tools. RESULTS: We identified three pathogenic variants in GCK, ABCC8 and HNF1A and several variants of uncertain significance in the cohort. Genotype-phenotype correlations and post-pregnancy follow-up data are described. CONCLUSIONS: This study provides the first insight into an underlying monogenic aetiology in non-obese females with GDM from an island population having a high prevalence of diabetes. It suggests that monogenic variants constitute an underestimated cause of diabetes detected in pregnancy, and that careful evaluation of GDM probands to identify monogenic disease subtypes is indicated.

Case Report: Identification of an HNF1B p.Arg527Gln mutation in a Maltese patient with atypical early onset diabetes and diabetic nephropathy.

BACKGROUND: The diagnosis of atypical non-autoimmune forms of diabetes mellitus, such as maturity onset diabetes of the young (MODY) presents several challenges, in view of the extensive clinical and genetic heterogeneity of the disease. In this report we describe a case of atypical non autoimmune diabetes associated with a damaging HNF1ß mutation. This is distinguished by a number of uncharacteristic clinical features, including early-onset obesity, the absence of renal cysts and diabetic nephropathy. HNF1ß-MODY (MODY5) is an uncommon form of monogenic diabetes that is often complicated by a wide array of congenital morphological anomalies of the urinary tract, including renal cysts. This report expands on the clinical phenotypes that have been described in the context of HNF1ß mutations, and is relevant as only isolated cases of diabetic nephropathy in the setting of MODY5 have been reported. CASE PRESENTATION: An obese Maltese female with non-autoimmune diabetes, microalbuminuria, glomerular hyperfiltration, fatty liver and no renal cysts was studied by whole exome sequencing to investigate potential genes responsible for the proband's phenotype. A rare missense mutation at a highly conserved site in exon 8 of HNF1ß was identified (c.1580G > A, NM_000458.3, p.Arg527Gln), with multiple in-silico predictions consistent with pathogenicity. This mutation has not been previously characterised. Additionally, several common susceptibility variants associated with early-onset obesity, polygenic type 2 diabetes and nephropathy were identified in the proband that could impose additional effects on the phenotype, its severity or its clinical course. CONCLUSION: This report highlights several atypical features in a proband with atypical diabetes associated with an HNF1ß missense mutation. It also reinforces the concept that monogenic causes of diabetes could be significant contributors to disease burden in obese individuals with atypical diabetes.

The Role of Untimed Blood Glucose in Screening for Gestational Diabetes Mellitus in a High Prevalent Diabetic Population.

Global prevalence increase of diabetes type 2 and gestational diabetes (GDM) has led to increased awareness and screening of pregnant women for GDM. Ideally screening for GDM should be done by an oral glucose tolerance test (oGTT), which is laborious and time consuming. A randomized glucose test incorporated with anthropomorphic characteristics may be an appropriate cost-effective combined clinical and biochemical screening protocol for clinical practice as well as cutting down on oGTTs. A retrospective observational study was performed on a randomized sample of pregnant women who required an OGTT during their pregnancy. Biochemical and anthropomorphic data along with obstetric outcomes were statistically analyzed. Backward stepwise logistic regression and receiver operating characteristics curves were used to obtain a suitable predictor for GDM without an oGTT and formulate a screening protocol. Significant GDM predictive variables were fasting blood glucose (p = 0.0001) and random blood glucose (p = 0.012). Different RBG and FBG cutoff points with anthropomorphic characteristics were compared to carbohydrate metabolic status to diagnose GDM without oGTT, leading to a screening protocol. A screening protocol incorporating IADPSG diagnostic criteria, BMI, and different RBG and FBG criteria would help predict GDM among high-risk populations earlier and reduce the need for oGTT test.

Biological and biochemical characteristics of a Mediterranean population with Gestational Diabetes Mellitus.

The interplay of various nutrients provided to the developing foetus determines the growth potential of the conceptus. This study assessed the inter-relationship between these nutrients in a Mediterranean population including 1062 pregnant, previously non-diabetic women. These underwent an oral glucose tolerance test (oGTT) and were accordingly classified into gestational hyperglycaemic and normoglycaemic groups. Fasting insulin, HbA1c, and lipid profiles were further assessed, and the anthropomorphic characteristics of the mother and child at birth were measured. Lipid profiles were compared between the two groups and related to the biological characteristics of the mother and child at birth. Gestational hyperglycaemia was significantly associated with elevated triglycerides (P<0.0001) and decreased low density lipoprotein cholesterol (LDL-C) (P=0.02). There were no significant changes in total cholesterol and high density lipoprotein cholesterol (HDL-C) levels. Maternal BMI correlated positively with the various glycaemic indices (P<0.0001) and triglycerides (P<0.0001), but inversely with cholesterol (P<0.0001), HDL-C (P<0.0001) and LDL-C (P<0.0001). The infant birth weight correlated positively with maternal body weight (P<0.0001), LDL-C (P<0.0001) and the glycaemic indices (P<0.0001), but negatively with cholesterol (P<0.0001), triglycerides (P<0.0001), HDL-C (P<0.0001) and FBG (P<0.0001). This study confirms that the maternal body mass index (BMI), insulin resistance, and LDL-C levels positively contribute towards foetal growth, whereas a negative correlation was noted with cholesterol, triglycerides, and HDL-C.

Synergistic effect on the treatment of menorrhagia by endometrial biopsy followed by contemporaneous insertion of the levonorgestrel intrauterine system.

OBJECTIVE: To evaluate the efficacy of endometrial biopsy followed by intrauterine system-releasing levonorgestrel (LNG-IUS) insertion in the treatment of women with menorrhagia. METHOD: This was a retrospective, non-comparative study. Ninety-two patients who had menorrhagia due to non-malignant causes were sequentially recruited into the study over a 3-year period (age range 29-51 years). Patients with a uterine size more than 12 weeks were not included. A LNG-releasing intrauterine system was inserted during the mid-cycle immediately after an endometrial biopsy was taken. One year after the closure of the study period, the women recruited were then contacted by telephone or by direct questioning at the outpatient clinic as to the outcome of the above treatment. RESULTS: The most common (15%) complaint regarding bleeding patterns at 3-6 months after insertion was spotting and intermenstrual bleeding. Following the introduction of the LNG-IUS, six women required a hysterectomy for various reasons. The remaining 86 women (93.5%) continued the use of LNG-IUS. CONCLUSION: LNG-IUS following an endometrial biopsy is an effective treatment for menorrhagia due to benign causes and could be an alternative to other forms of medical and surgical treatments.