Mutations In Hepatocyte Nuclear Factor-1beta Research Articles

LBODP032 Case Report Of A 13 Years Old Female With A Novel Pathogenic Variant In The Hnf1b Gene

Abstract Background MODY5 results from mutations in the gene encoding hepatocyte nuclear factor 1 homeobox B (HNF1B), a transcription factor critical in development of the pancreas, liver, intestines, and the urogenital tract (1). We report the case of a pediatric patient with a novel frameshift variant (p. Phe309SerfsTer18) in the HNF1B gene accounting for the co-occurrence of diabetes mellitus and structural renal abnormalities. Clinical case: A 13-years-old female with chronic kidney disease stage 3 (eGFR = 48 ml/min/1.73m2) secondary to congenital dysplastic-appearing left kidney and surgical removal of a cystic dysplastic right kidney was referred to our diabetes clinic for hyperglycemia. She reported long-standing polyuria and polydipsia previously attributed to her kidney disease. She required laparoscopic right nephrectomy at age 5 years due to increasing cyst size. Her left kidney also has small renal parenchymal cysts which have been monitored over time. There is no known family history of kidney disease, and grandparents have a history of diabetes. Laboratory investigation revealed a random blood glucose of 478 mg/dL and a hemoglobin A1c of 12.2%. She was not in diabetic ketoacidosis. She had a detectable insulin level of 5.1 mcIU/mL and C-peptide was 3.4 ng/mL. She was initially presumed to have Type 1 diabetes based on a relatively low insulin level and started on basal-bolus insulin (up to 0.59 units/kg of weight/day). Glycosylated hemoglobin was 8.7% one month after diagnosis. Glutamic acid decarboxylase, zinc transporter, islet cell, and insulin autoantibodies were not detected, however, and she was then suspected to have either Type 2 diabetes or MODY. Approximately one year later, she was taken off insulin due to hypoglycemia and managed only with metformin 500 mg twice daily. Next-generation sequencing revealed a de novo pathogenic variant in HNF1B causing a frameshift deletion (p. Phe309SerfsTer18). Genetic testing of parents was negative. Once her diagnosis of MODY5 was made, she was started on glipizide 2.5 mg once daily which has been titrated up to a dose of 5 mg with some success. However, she has since been re-started on insulin (up to 0.2 units/kg/day) due to hyperglycemia keeping in line with the MODY5 phenotype likely causing destruction of beta cells over time (1). Conclusion We report a case of MODY5 with a novel frameshift mutation (p. Phe309SerfsTer18) in the HNF1B gene. This case highlights the importance of screening for HNF-1B mutations in those patients with structural renal abnormalities and hyperglycemia, as diagnosis can guide management decisions and provide prognostic information. Reference Bellanné-Chantelot C, Chauveau D, Gautier JF, et al. Clinical spectrum associated with hepatocyte nuclear factor-1beta mutations. Ann Intern Med. 2004;140(7): 510-517. doi: 10.7326/0003-4819-140-7-200404060-0000 Presentation: No date and time listed

Elevated level of lysophosphatidic acid among patients with HNF1B mutations and its role in RCAD syndrome: a multiomic study

IntroductionPatients with hepatocyte nuclear factor-1 beta (HNF1B) mutations present a variable phenotype with two main symptoms: maturity onset diabetes of the young (MODY) and polycystic kidney disease (PKD).ObjectivesIdentification of serum metabolites specific for HNF1Bmut and evaluation of their role in disease pathogenesis.MethodsWe recruited patients with HNF1Bmut (N = 10), HNF1Amut (N = 10), PKD: non-dialyzed and dialyzed (N = 8 and N = 13); and healthy controls (N = 12). Serum fingerprinting was performed by LC-QTOF-MS. Selected metabolite was validated by ELISA (enzyme-linked immunosorbent assay) measurements and then biologically connected with HNF1B by in silico analysis. HepG2 were stimulated with lysophosphatidic acid (LPA) and HNF1B gene was knocked down (kd) by small interfering RNA. Transcriptomic analysis with microarrays and western blot measurements were performed.ResultsSerum levels of six metabolites including: arachidonic acid, hydroxyeicosatetraenoic acid, linoleamide and three LPA (18:1, 18:2 and 20:4), had AUC (the area under the curve) > 0.9 (HNF1Bmut vs comparative groups). The increased level of LPA was confirmed by ELISA measurements. In HepG2HNF1Bkd cells LPA stimulation lead to downregulation of many pathways associated with cell cycle, lipid metabolism, and upregulation of steroid hormone metabolism and Wnt signaling. Also, increased intracellular protein level of autotaxin was detected in the cells. GSK-3alpha/beta protein level and its phosphorylated ratio were differentially affected by LPA stimulation in HNF1Bkd and control cells.ConclusionsLPA is elevated in sera of patients with HNF1Bmut. LPA contributes to the pathogenesis of HNF1B-MODY by affecting Wnt/GSK-3 signaling.

O-182 Hnf1b Mutations In Patients With Congenital Abnormalities Of Kidney And Urinary Tract (cakut): Are We Screening Too Much?

Background and aims Hepatocyte nuclear factor 1 beta (HNF1B) is involved in the development of kidneys, liver, pancreas and urogenital tract. Disorders have an extremely high heterogeneity in phenotype. We aim to define accurate criteria for screening in a prospective cohort of patients. Methods Based on the phenotypic characteristics described in literature, we defined major, minor and extra-renal selection criteria. Major criteria were defined as fetal bilateral hyperechogenic kidneys; multicystic dysplastic kidney or renal agenesis; hypoplastic or dysplastic kidneys or cysts from unknown origin. Minor criteria were defined as ectopic kidney; vesico-ureteral reflux; hydronephrosis and extrarenal criteria as diabetes; hypomagnesemia; hyperuricemia; hypokalemia; liver function abnormalities or positive familial history. We included all patients from our paediatric and adult nephrology department from January 2010 till April 2013 presenting with at least one major or one minor criterion with extra-renal manifestations in the personal or familial history. Results We screened a prospective cohort of 252 patients fitting the criteria mentioned above and detected HNF1B mutations in 10% (n = 20), with a complete deletion being the most common (n = 10), besides duplication or sequence abnormalities. In our cohort the best predictors for finding HNF1B mutations were bilateral renal abnormalities (p Conclusions Based on a prospective single centre cohort, we demonstrated that HNF1B-mutations are responsible for approximately 10% of CAKUT cases. Nonetheless, bilateral renal anomalies or cysts from unknown origin were the best predictors. These criteria might be useful for a more restricted screening protocol, but should be reaffirmed in a larger multicenter cohort.

Hypoplastic Glomerulocystic Kidney Disease and Hepatoblastoma

Hypoplastic glomerulocystic kidney disease is an autosomal dominant disorder caused by mutations in hepatocyte nuclear factor-1beta. Hepatoblastoma is a sporadic occurring tumor of embryonal origin that has been associated with the several overgrowth syndromes. We report a case of concomitant hypoplastic glomerulocystic kidney disease and hepatoblastoma. Review of the literature identified 4 other patients with a similar association. We propose that hypoplastic glomerulocystic kidney disease and hepatoblastoma represent a possible association, and we excluded mutations in hepatocyte nuclear factor-1beta in our patient as causative of this putative association.

Horseshoe kidney malformation in Turner syndrome is not associated with HNF-1β gene mutations

Mutations in hepatocyte nuclear factor-1beta (HNF-1beta) gene cause a subtype of maturity-onset diabetes of the young (MODY5), whose clinical features are pancreatic beta-cell dysfunction, renal malformations, and in some females, internal genital malformations. Recently, we reported the first case of MODY5 and horseshoe kidney. The patient was the only male in a three-generation family with five affected females carrying renal cysts or dysplastic kidney. Diabetes mellitus, horseshoe kidney, and X chromosome monosomy or mosaicism can be observed in Turner syndrome (TS). In particular, diabetes mellitus affects about 50% and horseshoe kidney occurs in approximately 16% of patients. To investigate whether mutations/polymorphisms of HNF-1beta and X monosomy influence horseshoe kidney development, we evaluated HNF-1beta gene sequence in 13 patients with TS and several kidney abnormalities. Analysis of the nine exons including intron-exon boundaries of HNF-1beta revealed the presence in two subjects (15%) of a known intronic polymorphism, IV8+48insC. No specific variants were found. We conclude there is no direct relationship between horseshoe kidney in TS and mutation or polymorphism of HNF-1beta gene, but we speculate that target gene(s) of HNF-1beta, likely mapped on the X chromosome, is/are responsible of the horseshoe kidney formation in TS.

Diagnosis and Management of Maturity-Onset Diabetes of the Young

Maturity-onset diabetes of the young (MODY) is a dominantly inherited form of non-ketotic diabetes mellitus. It results from a primary defect of insulin secretion, and usually develops at childhood, adolescence, or young adulthood. MODY is a heterogeneous disease with regard to genetic, metabolic, and clinical features. All MODY genes have not been identified, but heterozygous mutations in six genes cause the majority of the MODY cases. By far MODY2 (due to mutations of the glucokinase gene) and MODY3 (due to mutations in hepatocyte nuclear factor-1alpha) are the most frequent. As with MODY3, all the other MODY subtypes are associated with mutations in transcription factors. The clinical presentations of the different MODY subtypes differ, particularly in the severity and the course of the insulin secretion defect, the risk of microvascular complications of diabetes, and the defects associated with diabetes. Patients with MODY2 have mild, asymptomatic, and stable hyperglycemia that is present from birth. They rarely develop microvascular disease, and seldom require pharmacologic treatment of hyperglycemia. In patients with MODY3, severe hyperglycemia usually occurs after puberty, and may lead to the diagnosis of type 1 diabetes. Despite the progression of insulin defects, sensitivity to sulfonylureas may be retained in MODY3 patients. Diabetic retinopathy and nephropathy frequently occur in patients with MODY3, making frequent follow-up mandatory. By contrast, other risk factors are not present in patients with MODY and the frequency of cardiovascular disease is not increased. The clinical spectrum of MODY is wider than initially described, and might include multi-organ involvement in addition to diabetes. In patients with MODY5, due to mutations in hepatocyte nuclear factor-1beta, diabetes is associated with pancreatic atrophy, renal morphologic and functional abnormalities, and genital tract and liver test abnormalities. Although MODY is dominantly inherited, penetrance or expression of the disease may vary and a family history of diabetes is not always present. Thus, the diagnosis of MODY should be raised in various clinical circumstances. Molecular diagnosis has important consequences in terms of prognosis, family screening, and therapy.

Enlarged nephrons and severe nondiabetic nephropathy in hepatocyte nuclear factor-1β (HNF-1β) mutation carriers

Mutations in hepatocyte nuclear factor-1beta (HNF-1beta) lead to a syndrome with diabetes and urogenital malformations [maturity onset of diabetes of the young, type 5 (MODY5)]. The aim of this study was to perform a clinicopathologic investigation of the renal disease in members of a Norwegian family with the HNF-1beta mutation R137-K161del. The study was based on long-term clinical observations of five mutation carriers, combined with renal biopsies from four of these. The biopsies were examined by light microscopy, immunohistochemistry, and transmission electron microscopy. The diameter of the glomerulus, proximal and distal tubules, in addition to thickness of the glomerular basement membrane (GBM), were measured in light microscopic slides and transmission electron micrographs. The results were compared with biopsies from adult patients with diabetic glomerulopathy, glomerulonephritis, and/or benign nephrosclerosis, and children with minimal-change glomerulopathy or glomerulonephritis, respectively. Clinically, there was a wide intrafamilial variation from stable or slightly increasing serum creatinine to progressive renal failure and end-stage renal disease (ESRD). In all cases, the kidney disease was diagnosed prior to diabetes. Hypertrophy of the proximal and distal tubules as well as enlarged glomeruli were found in three of four mutation carriers. Essentially normal nephrons were found in the 10-year-old boy. The thickness of the GBM was considered near normal in all mutation carriers. Oligomeganephronia was found in one patient. Histopathologic and morphometric studies of kidney biopsies from four carriers of an HNF-1beta mutation revealed enlarged glomeruli and tubular structures. Long-term clinical follow-up demonstrated that the renal disease developed prior to and independently of diabetes. Finally, there is a wide phenotypic variation of the renal disease caused by HNF-1beta mutations.