Genetic insights into fetal kidney development: Variants in HNF1A and PKHD1 genes.

The orchestration of fetal kidney development involves the precise control of numerous genes, including HNF1A, HNF1B and PKHD1. Understanding the genetic factors influencing fetal kidney development is essential for unraveling the complexities of renal disorders. This study aimed to search for disease-causing variants in HNF1A, HNF1B, PKHD1 genes, among fetus and babies or via parental samples, using sanger sequencing, NGS technologie and MLPA. The study revealed an absence of gene deletions and disease-causing variants in the HNF1B gene. However, five previously SNPs in the HNF1A gene were identified in four patients (patients 1, 2, 3, and 4). These include c.51C > G (Exon1, p. Leu17=), c.79A > C (Exon1, p. Ile27Leu), c.1375C > T (Exon7, p. Leu459=), c.1460G > A (Exon7, p. Ser487Asn), and c.1501 + 7G > A (Intron7). Additionally, in addition to previously SNPs identified, a de novo heterozygous missense mutation (p.E508K) was detected in patient 4. Furthermore, a heterozygous mutation in exon 16 (p. Arg494*; c.1480C > T) was identified in both parents of patient 5, allowing predictions of fetal homozygosity. Bioinformatic analyses predicted the effects of the c.1522G > A mutation (p.E508K) on splicing processes, pre-mRNA structures, and protein instability and conformation. Similarly, the c.1480C > T mutation (p. Arg494*) was predicted to introduce a premature codon stop, leads to the production of a shorter protein with altered or impaired function. Identification of variants in the HNF1A and in PKHD1 genes provides valuable insights into the genetic landscape of renal abnormalities in affected patients. These findings underscore the heterogeneity of genetic variants contributing to renal disorders and emphasize the importance of genetic screening.

Variable phenotype and genotype of pediatric patients with HNF1B nephropathy.

AIMS: Hepatocyte nuclear factor 1ß (HNF1B) mutations are the most common monogenic cause of congenital anomalies of the kidney and urinary tract (CAKUT). We aimed to investigate clinical and genetic characteristics of patients with HNF1B nephropathy to expand its phenotypic and genetic spectrum. MATERIALS AND METHODS: This retrospective cohort study included 16 unrelated pediatric patients (6 females, 10 males) from 13 families with genetically confirmed HNF1B-related nephropathy. RESULTS: Abnormal prenatal kidney abnormalities were present in 13 patients (81.3%). The most common antenatal kidney abnormality was kidney cysts, which were observed in 8 patients (61.5%). Urinary system abnormalities (vesicoureteral reflux (VUR) and ureteropelvic junction obstruction (UPJO)) were present in 4 patients (25%). HNF1B analysis uncovered missense variants in 4 families (30.8%) as the most common genetic abnormality. In addition, 4 novel pathological variations have been defined. During follow-up, hypomagnesemia and hyperuricemia were observed in 7 (43.8%) and 5 patients (31.3%), respectively. None of the patients with a missense variant had hypomagnesemia. However, 7 out of 12 patients (58.3%) with a non-missense variant had hypomagnesemia (p = 0.09). None of the patients had an HNF1B score below 8, and the mean score was 15.3 ± 4.4. The mean follow-up period was 7.4 ± 5.0 years. While 100% of patients (n = 4) with missense variants were in various stages of CKD (CKD2: 2 patients, CKD3: 2 patients), 25% of those with non-missense variants had CKD (CKD2, 3, and 5; 1 patient, respectively) (p = 0.026). CONCLUSION: Patients with HNF1B-associated disease have concomitant urinary system abnormalities such as VUR or UPJO. Missense variants seem to be the most common pathological variations in HNF1B gene and have higher risk of CKD.

High prevalence of copy number variations in the Japanese participants with suspected MODY.

Maturity-Onset Diabetes of the Young (MODY) is a diabetes mellitus subtype caused by a single gene. The detection rate of the responsible gene is 27% in the United Kingdom, indicating that the causative gene remains unknown in the majority of clinically diagnosed MODY cases. To improve the detection rate, we applied comprehensive genetic testing using whole exome sequencing (WES) followed by Multiplex Ligation-dependent Probe Amplification (MLPA) and functional analyses. Twenty-one unrelated Japanese participants with MODY were enrolled in the study. To detect copy number variations (CNVs), WES was performed first, followed by MLPA analysis for participants who were negative on the basis of WES. Undetermined variants were analyzed according to their functional properties. WES identified 7 pathogenic and 3 novel likely pathogenic variants in the 21 participants. Functional analyses revealed that 1 in 3 variants was pathogenic. MLPA analysis applied to the remaining 13 undetermined samples identified 4 cases with pathogenic CNVs: 3 in HNF4A and 1 in HNF1B. Pathogenic variants were identified in 12 participants (12/21, 57.1%) - relatively high rate reported to date. Notably, one-third of the participants had CNVs in HNF4A or HNF1B, indicating a limitation of WES-only screening.

Human pluripotent stem cell-derived kidney organoids reveal tubular epithelial pathobiology of heterozygous HNF1B-associated dysplastic kidney malformations.

Hepatocyte nuclear factor 1B (HNF1B) encodes a transcription factor expressed in developing human kidney epithelia. Heterozygous HNF1B mutations are the commonest monogenic cause of dysplastic kidney malformations (DKMs). To understand their pathobiology, we generated heterozygous HNF1B mutant kidney organoids from CRISPR-Cas9 gene-edited human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) reprogrammed from a family with HNF1B-associated DKMs. Mutant organoids contained enlarged malformed tubules displaying deregulated cell turnover. Numerous genes implicated in Mendelian kidney tubulopathies were downregulated, and mutant tubules resisted the cyclic AMP (cAMP)-mediated dilatation seen in controls. Bulk and single-cell RNA sequencing (scRNA-seq) analyses indicated abnormal Wingless/Integrated (WNT), calcium, and glutamatergic pathways, the latter hitherto unstudied in developing kidneys. Glutamate ionotropic receptor kainate type subunit 3 (GRIK3) was upregulated in malformed mutant nephron tubules and prominent in HNF1B mutant fetal human dysplastic kidney epithelia. These results reveal morphological, molecular, and physiological roles for HNF1B in human kidney tubule differentiation and morphogenesis illuminating the developmental origin of mutant-HNF1B-causing kidney disease.

The Phenotypic Variability Associated with Hepatocyte Nuclear Factor 1B Genetic Defects Poses Challenges in Both Diagnosis and Therapy.

The evolving landscape of clinical genetics is becoming increasingly relevant in the field of nephrology. HNF1B-associated renal disease presents with a diverse array of renal and extrarenal manifestations, prominently featuring cystic kidney disease and diabetes mellitus. For the genetic analyses, whole exome sequencing (WES) and multiplex ligation-dependent probe amplification (MLPA) were performed. Bioinformatics analysis was performed with Ingenuity Clinical Insights software (Qiagen). The patient's electronic record was utilized after receiving informed consent. In this report, we present seven cases of HNF1B-associated kidney disease, each featuring distinct genetic abnormalities and displaying diverse extrarenal manifestations. Over 12 years, the mean decline in eGFR averaged -2.22 ± 0.7 mL/min/1.73 m2. Diabetes mellitus was present in five patients, kidney dysplastic lesions in six patients, pancreatic dysplasia, hypomagnesemia and abnormal liver function tests in three patients each. This case series emphasizes the phenotypic variability and the fast decline in kidney function associated with HNF-1B-related disease. Additionally, it underscores that complex clinical presentations may have a retrospectively straightforward explanation through the use of diverse genetic analytical tools.

In Vitro Functional Analysis Can Aid Precision Diagnostics of HNF1B-MODY.

Precision medicine relies on accurate and consistent classification of sequence variants. A correct diagnosis of hepatocyte nuclear factor (HNF) 1B maturity-onset diabetes of the young, caused by pathogenic variants in the HNF1B gene, is important for optimal disease management and prognosis, and it has implications for genetic counseling and follow-up of at-risk family members. We hypothesized that the functional characterization could provide valuable information to assist the interpretation of pathogenicity of HNF1B variants. Using different in vitro functional assays, variants identified among 313 individuals, suspected to have monogenic diabetes with or without kidney disease, were characterized. The data from the functional assays were subsequently conjugated with obtained clinical, biochemical, and in silico data. Two variants (p.A167P, p.H336Pfs∗22) showed severe loss of function due to impaired transactivation, reduced DNA binding (p.A167P), and mRNA instability (p.A167P). Although both these variant carriers were diagnosed with diabetes, the p.H336Pfs∗22 carrier also had congenital absence of a kidney, which is a characteristic trait for HNF1B maturity-onset diabetes of the young. Functional analysis of the p.A167P variant revealed damaging effects on HNF-1B protein function, which may warrant imaging of the kidneys and/or pancreas. In addition, the current study has generated important data, including evidence supporting the benign functional impact of five variants (p.D82N, p.T88A, p.N394D, p.V458G, and p.T544A), and piloting new approaches that will prove critical for the growth of HNF1B-diabetes diagnosis.

Semaglutide as a potential therapeutic alternative for HNF1B-MODY: a case study.

Maturity-onset diabetes of the young (MODY) is a grouping of monogenic disorders. It is characterized by dominantly inherited, non-insulin-dependent diabetes. MODY is relatively rare, encompassing up to 3.5% in those diagnosed under 30 years of age. Specific types are most commonly treated with sulfonylurea, particularly those identified as HNF4A-MODY and HNF1A-MODY. HNF1B-MODY is another type that is most frequently managed with insulin therapy but lacks a defined precision treatment. We present an 18-year-old, non-obese female patient diagnosed with HNF1B-MODY. She displays complete gene deletion, a renal cyst, and hypomagnesemia. Her treatment plan includes both long- and short-acting insulin, though she frequently encountered hypoglycemia and hyperglycemia. Semaglutide, a GLP-1RA, was administered weekly over 4 months. The patient's glucose level was continuously tracked using Dexcom's Continuous Glucose Monitoring system. The data suggested a notable improvement in her condition: time-in-range (TIR) increased from 70% to 88%, with some days achieving 100%, and the frequency of hypoglycemic episodes, indicated by time-below-range values, fell from 5% to 1%. The time-above-range values also dropped from 25% to 10%, and her HbA1c levels declined from 7% to 5.6%. During the semaglutide therapy, we were able to discontinue her insulin treatment. Additionally, her body mass index (BMI) was reduced from 24.1 to 20.1 kg/m2. However, the semaglutide treatment was halted after 4 months due to side effects such as nausea, vomiting, and reduced appetite. Other contributing factors included exam stress and a COVID-19 infection, which forced a switch back to insulin. Her last recorded HbA1c level under exclusive insulin therapy rose to 7.1%, and her BMI increased to 24.9 kg/m2. In conclusion, semaglutide could potentially replace insulin to improve glucose variability, TIR, and HbA1c in patients with HNF1B-MODY. However, more extensive studies are required to confirm its long-term safety and efficacy.

1H, 13C and 15N backbone resonance assignments of hepatocyte nuclear factor-1-beta (HNF1ß) POUS and POUHD.

Hepatocyte nuclear factor 1ß (HNF1ß) is a transcription factor that plays a key role in the development and function of the liver, pancreas, and kidney. HNF1ß plays a key role in early vertebrate development and the morphogenesis of these organs. In humans, heterozygous mutations in the HNF1B gene can result in organ dysplasia, making it the most common cause of developmental renal diseases, including renal cysts, renal malformations, and familial hypoplastic glomerular cystic kidney disease. Pathogenic variants in the HNF1B gene are known to cause various diseases, including maturity-onset diabetes of the young and developmental renal diseases. This study presents the backbone resonance assignments of HNF1ß POUS and POUHD domains, which are highly conserved domains required for the recognition of double-stranded DNA. Our data will be useful for NMR studies to verify the altered structures and functions of mutant HNF1B proteins that can induce developmental renal diseases, including renal cysts, renal malformations, and familial hypoplastic glomerular cystic kidney disease. This study will provide the structural basis for future studies to elucidate the molecular mechanisms underlying how mutations in HNF1ß cause diseases.

Development of a tool for predicting HNF1B mutations in children and young adults with congenital anomalies of the kidneys and urinary tract.

BACKGROUND: We aimed to develop a tool for predicting HNF1B mutations in children with congenital abnormalities of the kidneys and urinary tract (CAKUT). METHODS: The clinical and laboratory data from 234 children and young adults with known HNF1B mutation status were collected and analyzed retrospectively. All subjects were randomly divided into a training (70%) and a validation set (30%). A random forest model was constructed to predict HNF1B mutations. The recursive feature elimination algorithm was used for feature selection for the model, and receiver operating characteristic curve statistics was used to verify its predictive effect. RESULTS: A total of 213 patients were analyzed, including HNF1B-positive (mut + , n = 109) and HNF1B-negative (mut - , n = 104) subjects. The majority of patients had mild chronic kidney disease. Kidney phenotype was similar between groups, but bilateral kidney anomalies were more frequent in the mut + group. Hypomagnesemia and hypermagnesuria were the most common abnormalities in mut + patients and were highly selective of HNF1B. Hypomagnesemia based on age-appropriate norms had a better discriminatory value than the age-independent cutoff of 0.7 mmol/l. Pancreatic anomalies were almost exclusively found in mut + patients. No subjects had hypokalemia; the mean serum potassium level was lower in the HNF1B cohort. The abovementioned, discriminative parameters were selected for the model, which showed a good performance (area under the curve: 0.85; sensitivity of 93.67%, specificity of 73.57%). A corresponding calculator was developed for use and validation. CONCLUSIONS: This study developed a simple tool for predicting HNF1B mutations in children and young adults with CAKUT.

Prenatal diagnosis and perinatal findings of 17q12 microdeletion encompassing HNF1B in a fetus with bilateral hyperechogenic kidneys on fetal ultrasound and mild renal abnormality after birth, and a review of the literature of prenatal diagnosis of 17q12 microdeletion.

OBJECTIVE: We present prenatal diagnosis and perinatal findings of 17q12 microdeletion encompassing HNF1B in a fetus with bilateral hyperechogenic kidneys on fetal ultrasound and mild renal abnormality after birth, and a review of the literature. CASE REPORT: A 36-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes showed a de novo 1.38-Mb 17q12 microdeletion encompassing LHX1 and HNF1B. The parents did not have such a microdeletion. Prenatal ultrasound showed bilateral hyperechogenic kidneys with normal corticomedullary (CM) differentiation. The parents elected to continue the pregnancy, and a grossly normal 3180-g male baby was delivered at 39 weeks of gestation. aCGH analysis on the cord blood DNA revealed arr [GRCh37 (hg19)] 17q12 (34,856,055-36,248,918) × 1.0 with a 1.393-Mb microdeletion encompassing the genes of MYO19, PIGW, GGNBP2, DHRS11, MRM1, LHX1, AATF, ACACA, TADA2A, DUSP14, SYNRG, DDX52 and HNF1B. When follow-up at age 2 years and 4 months, the renal ultrasound revealed bilateral increased renal echogenicity with normal CM differentiation and small left renal cysts. The blood test revealed BUN = 28 mg/dL (normal: 5-18 mg/dL) and creatinine = 0.5 mg/dL (normal: 0.2-0.4 mg/dL). CONCLUSION: 17q12 microdeletion encompassing LHX1 and HNF1B at prenatal diagnosis may present variable clinical spectrum with bilateral hyperechogenic kidneys on fetal ultrasound and mild renal abnormality after birth. Prenatal diagnosis of fetal hyperechogenic kidneys should raise a suspicion of 17q12 microdeletion syndrome.

Evaluation of HNF1B, KLK3, ELAC2, TMPRSS2-ERG, and CTNNB1 polymorphisms associated with prostate cancer in samples of patients from HUPE-UERJ.

PURPOSE: Prostate cancer (PCa) is the leading cause of death among men in 48 countries. Genetic alterations play a significant role in PCa carcinogenesis. For the hypothesis of this research, five unique polymorphisms (SNP) were investigated in different genes that showed to be associated in different ways with PCa: rs4430796, rs2735839, rs4792311, rs12329760, and rs28931588, respectively for the genes HNF1B, KLK3, ELAC2, TMPRSS2-ERG, and CTNNB1. PATIENTS AND METHODS: Blood samples from 426 subjects were evaluated: 290 controls (161 females and 129 males) and 136 PCa patients. SNP were determined by real-time polymerase chain reaction. TaqMan SNP genotyping assay. In the control samples, the SNPs were defined in association with the self-reported ethnicity, and in 218 control samples with markers with ancestry indicators. The genes were in Hardy-Weinberg equilibrium. One hundred and seventy control samples were matched by ethnicity for comparison with the PCa samples. RESULTS: The G allele at rs28931588 was monomorphic in both patients and controls studied. Significant differences were observed in allelic and genotypic frequencies between the control and Pca samples in rs2735839 (KLK3; p = 0.002 and χ2 = 8.73 and p = 0.01, respectively), by the global frequency and in the dominant model rs2735839_GG (odds ratio [OR] = 0.51, p = 0.02). AA and GA genotypes at rs4792311 (ELAC2) were more frequent in patients with Gleason 7(4 + 3), 8, and 9 (n = 37%-59.7%) compared to patients with Gleason 6 and 7(3 + 4) (n = 26%-40.0%) conferring a protective effect on the GG genotype (OR = 0.45, p = 0.02). The same genotype showed an OR = 2.71 (p = 0.01) for patients with low severity. The HNF1B-KLK3-ELAC2-TMPRSS2-ERG haplotypes: GAAT, AAAT, GAGT, and AAGT were more frequent in patients with Pca with OR ranging from 4.65 to 2.48. CONCLUSIONS: Higher frequencies of risk alleles were confirmed in the SNPs, KLK3 rs2735839_A, ELAC2 rs4792311_A, and TMPRSS2 rs12329760_T in patients with Pca. Rs2735839_A was associated with risk of Pca and rs4792311_A with severity and Gleason score of 7(4 + 3) or greater. There is a need for careful observation of rs2735839 and rs4792311 in association with the prostatic biopsy due to the increased risk of Pca.

Hepatocyte nuclear factor 1B deletion, but not intragenic mutation, might be more susceptible to hypomagnesemia.

AIMS: HNF1B syndrome is caused by defects in the hepatocyte nuclear factor 1B (HNF1B) gene, which leads to maturity-onset diabetes of the young type 5 and congenital organ malformations. This study aimed to identify a gene defect in a patient presenting with diabetes and severe diarrhea, while also analyzing the prevalence of hypomagnesemia and its correlation with the HNF1B genotype. MATERIALS AND METHODS: Whole exome sequencing was used to identify responsible point mutations and small indels in the proband and their family members. Multiplex ligation-dependent probe amplification was carried out to identify HNF1B deletions. Furthermore, an analysis of published data on 539 cumulative HNF1B cases, from 29 literature sources, was carried out to determine the correlation between the HNF1B genotype and the phenotype of serum magnesium status. RESULTS: Using multiplex ligation-dependent probe amplification, we identified a de novo heterozygous HNF1B deletion in the patient, who showed dorsal pancreas agenesis and multiple kidney cysts, as detected by magnetic resonance imaging. Magnesium supplementation effectively alleviated the symptoms of diarrhea. Hypomagnesemia was highly prevalent in 192 out of 354 (54.2%) patients with HNF1B syndrome. Compared with patients with intragenic mutations, those with HNF1B deletions were more likely to suffer from hypomagnesemia, with an odds ratio of 3.1 (95% confidence interval 1.8-5.4). CONCLUSIONS: Hypomagnesemia is highly prevalent in individuals with HNF1B syndrome, and those with HNF1B deletion are more susceptible to developing hypomagnesemia compared with those with intragenic mutations. The genotype-phenotype associations in HNF1B syndrome have significant implications for endocrinologists in terms of genotype detection, treatment decisions and prognosis assessment.

Characterization of the prenatal renal phenotype associated with 17q12, HNF1B, microdeletions.

OBJECTIVE: Recurrent deletions involving 17q12 are associated with a variety of clinical phenotypes, including congenital abnormalities of the kidney and urinary tract (CAKUT), maturity onset diabetes of the young, type 5, and neurodevelopmental disorders. Structural and/or functional renal disease is the most common phenotypic feature, although the prenatal renal phenotypes and the postnatal correlates have not been well characterized. METHOD: We reviewed pre- and postnatal medical records of 26 cases with prenatally or postnatally identified 17q12/HNF1B microdeletions (by chromosomal microarray or targeted gene sequencing), obtained through a multicenter collaboration. We specifically evaluated 17 of these cases (65%) with reported prenatal renal ultrasound findings. RESULTS: Heterogeneous prenatal renal phenotypes were noted, most commonly renal cysts (41%, n = 7/17) and echogenic kidneys (41%), although nonspecific dysplasia, enlarged kidneys, hydronephrosis, pelvic kidney with hydroureter, and lower urinary tract obstruction were also reported. Postnatally, most individuals developed renal cysts (73%, 11/15 live births), and there were no cases of end-stage renal disease during childhood or the follow-up period. CONCLUSION: Our findings demonstrate that copy number variant analysis to assess for 17q12 microdeletion should be considered for a variety of prenatally detected renal anomalies. It is important to distinguish 17q12 microdeletion from other etiologies of CAKUT as the prognosis for renal function and presence of associated findings are distinct and may influence pregnancy and postnatal management.

Renal and extra-renal phenotypes in a fetus with a de novo pathogenic variant in the HNF1B gene.

We report a fetus with prenatal ultrasound at 21 gestational weeks showing left cystic renal dysplasia with subcapsular cysts and echogenic parenchyma, right echogenic kidney with absent corticomedullary differentiation, and left congenital diaphragmatic hernia (CDH) with bowel herniation, with intestinal atresia (IA) found on postmortem examination. Whole genome sequencing of fetal blood DNA revealed a heterozygous pathogenic variant c.344 + 2 T>G in the HNF1B gene (NM_000458). Sanger sequencing of the parental samples suggested that it arose de novo in the fetus. HNF1B-associated disorders affect multiple organs with significant phenotypic heterogeneity. In pediatric and adult patients, renal cystic disease and cystic dysplasia are the dominant phenotypes. In prenatal settings, renal anomaly is also the most common presentation, typically with bilateral hyperechogenic kidneys. Our case presented with two uncommon extra-renal phenotypes of CDH and IA besides the typical bilateral cystic renal dysplasia. This association has been reported in fetuses with 17q12 microdeletion but not with HNF1B point mutation. Our case is the first prenatal report of such an association and highlights the possible causal relationship of HNF1B defects with CDH and IA in addition to the typical renal anomalies.

Sortilin-induced lipid accumulation and atherogenesis are suppressed by HNF1b SUMOylation promoted by flavone of Polygonatum odoratum. / çŽ‰ç«¹é»„é ®é€šè¿‡ä¿ƒè¿›HNF1b蛋白的SUMO化修饰抑制sortilinä»‹å¯¼çš„è„‚è´¨ç§¯ç´¯åŠåŠ¨è„‰ç²¥æ ·ç¡¬åŒ–.

This study aims to investigate the impact of hepatocyte nuclear factor 1ß (HNF1b) on macrophage sortilin-mediated lipid metabolism and aortic atherosclerosis and explore the role of the flavone of Polygonatum odoratum (PAOA-flavone)-promoted small ubiquitin-related modifier (SUMO) modification in the atheroprotective efficacy of HNF1b. HNF1b was predicted to be a transcriptional regulator of sortilin expression via bioinformatics, dual-luciferase reporter gene assay, and chromatin immunoprecipitation. HNF1b overexpression decreased sortilin expression and cellular lipid contents in THP-1 macrophages, leading to a depression in atherosclerotic plaque formation in low-density lipoprotein (LDL) receptor-deficient (LDLR-/-) mice. Multiple SUMO1-modified sites were identified on the HNF1b protein and co-immunoprecipitation confirmed its SUMO1 modification. The SUMOylation of HNF1b protein enhanced the HNF1b-inhibited effect on sortilin expression and reduced lipid contents in macrophages. PAOA-flavone treatment promoted SUMO-activating enzyme subunit 1 (SAE1) expression and SAE1-catalyzed SUMOylation of the HNF1b protein, which prevented sortilin-mediated lipid accumulation in macrophages and the formation of atherosclerotic plaques in apolipoprotein E-deficient (ApoE-/-) mice. Interference with SAE1 abrogated the improvement in lipid metabolism in macrophage cells and atheroprotective efficacy in vivo upon PAOA-flavone administration. In summary, HNF1b transcriptionally suppressed sortilin expression and macrophage lipid accumulation to inhibit aortic lipid deposition and the development of atherosclerosis. This anti-atherosclerotic effect was enhanced by PAOA-flavone-facilitated, SAE1-catalyzed SUMOylation of the HNF1b protein.

Clinicopathological correlations of endometrioid and clear cell carcinomas in the uterus and ovary.

Endometrioid carcinoma (EC) and clear cell carcinoma (CC) are associated with endometrial tissue hyperplasia and endometriosis, and they occur in the endometrium and ovaries. However, detailed differences between these tumors based on immunostaining are unclear; therefore, in this study, we aimed to analyze the clinicopathological correlations between these tumors using immunostaining and to develop new treatments based on histological subtypes. Immunohistochemistry was used to investigate differentially expressed hypoxia-associated molecules (hypoxia-inducible factor-1 subunit alpha [HIF-1α], forkhead box O1, prostate-specific membrane antigen, signal transducer and activator of transcription 3 [STAT3], hepatocyte nuclear factor 1ß [HNF-1ß], aquaporin-3, and vimentin [VIM]) between these carcinomas because of the reported association between CC and ischemia. Immunostaining and clinicopathological data from 70 patients (21 uterine endometrioid carcinomas [UECs], 9 uterine cell carcinomas, 20 ovarian endometrioid carcinomas [OECs], and 20 ovarian cell carcinomas [OCCs]) were compared. HIF-1α and prostate-specific membrane antigen expression levels were higher in UEC and OCC than in uterine cell carcinomas and OEC. STAT3 was slightly overexpressed in UEC. Additionally, forkhead box O1 expression was either absent or significantly attenuated in all ECs. VIM and AQ3 were highly expressed in UEC, whereas HNF-1ß expression was higher in OCC. UEC, OEC, and OCC were more common in the uterine fundus, left ovary, and right ovary, respectively. Ovarian endometriosis was strongly associated with EC. Our findings suggest that UEC and OCC share a carcinogenic pathway that involves HIF-1α induction under hypoxic conditions via STAT3 expression, resulting in angiogenesis. Furthermore, the anatomical position of carcinomas may contribute to their carcinogenesis. Finally, aquaporin-3 and VIM demonstrate strong potential as biomarkers for UEC, whereas HNF-1ß expression is a crucial factor in CC development. These differences in tumor site and histological subtypes shown in this study will lead to the establishment of treatment based on histological and immunohistological classification.

HNF1B variant without hyperglycaemia as a cause of isolated profound hypomagnesaemia.

A young man presented unconscious with severe hyponatraemia, hypokalaemia, hypomagnesaemia and metabolic alkalosis. After 4 months of treatment in hospital, the hypomagnesaemia persisted. The patient had no signs of diabetes mellitus, and radiology showed no abnormalities of the kidneys, pancreas or genitourinary tract. A parenteral magnesium load demonstrated renal wasting with increased fractional urinary excretion of magnesium. Genetic tests for Gitelman as well as Bartter syndromes were negative. However, a wider genetic panel revealed that the patient was heterozygous for a deletion on chromosome band 17q12, encompassing the whole HNF1B gene.This case highlights the importance of considering pathogenic HNF1B variants in isolated profound hypomagnesaemia caused by renal wasting. Pathogenic HNF1B variants may partly mimic hypomagnesaemia found in Gitelman and Bartter syndromes and may be present without other features linked to HNF1B variants, including diabetes mellitus.

The Landscape of HNF1B Deficiency: A Syndrome Not Yet Fully Explored.

The hepatocyte nuclear factor 1ß (HNF1B) gene is involved in the development of specialized epithelia of several organs during the early and late phases of embryogenesis, performing its function mainly by regulating the cell cycle and apoptosis pathways. The first pathogenic variant of HNF1B (namely, R177X) was reported in 1997 and is associated with the maturity-onset diabetes of the young. Since then, more than 230 different HNF1B variants have been reported, revealing a multifaceted syndrome with complex and heterogenous genetic, pathologic, and clinical profiles, mainly affecting the pediatric population. The pancreas and kidneys are the most frequently affected organs, resulting in diabetes, renal cysts, and a decrease in renal function, leading, in 2001, to the definition of HNF1B deficiency syndrome, including renal cysts and diabetes. However, several other organs and systems have since emerged as being affected by HNF1B defect, while diabetes and renal cysts are not always present. Especially, liver involvement has generally been overlooked but recently emerged as particularly relevant (mostly showing chronically elevated liver enzymes) and with a putative relation with tumor development, thus requiring a more granular analysis. Nowadays, HNF1B-associated disease has been recognized as a clinical entity with a broader and more variable multisystem phenotype, but the reasons for the phenotypic heterogeneity are still poorly understood. In this review, we aimed to describe the multifaceted nature of HNF1B deficiency in the pediatric and adult populations: we analyzed the genetic, phenotypic, and clinical features of this complex and misdiagnosed syndrome, covering the most frequent, unusual, and recently identified traits.