GATA4 Mutations Research Articles

Gata6 functions in zebrafish endoderm to regulate late differentiating arterial pole cardiogenesis.

Mutations in GATA6 are associated with congenital heart disease, most notably conotruncal structural defects. However, how GATA6 regulates cardiac morphology during embryogenesis is undefined. We used knockout and conditional mutant zebrafish alleles to investigate the spatiotemporal role of gata6 during cardiogenesis. Loss of gata6 specifically impacts atrioventricular valve formation and recruitment of epicardium, with a prominent loss of arterial pole cardiac cells, including those of the ventricle and outflow tract. However, there are no obvious defects in cardiac progenitor cell specification, proliferation or death. Conditional loss of gata6 starting at 24 h is sufficient to disrupt the addition of late differentiating cardiomyocytes at the arterial pole, with decreased expression levels of anterior secondary heart field (SHF) markers spry4 and mef2cb. Conditional loss of gata6 in the endoderm is sufficient to phenocopy the straight knockout, resulting in a significant loss of ventricular and outflow tract tissue. Exposure to a Dusp6 inhibitor largely rescues the loss of ventricular cells in gata6-/- larvae. Thus, gata6 functions in endoderm are mediated by FGF signaling to regulate the addition of anterior SHF progenitor derivatives during heart formation.

GATA6 regulates WNT and BMP programs to pattern precardiac mesoderm during the earliest stages of human cardiogenesis.

Haploinsufficiency for GATA6 is associated with congenital heart disease (CHD) with variable comorbidity of pancreatic or diaphragm defects, although the etiology of disease is not well understood. Here, we used cardiac directed differentiation from human embryonic stem cells (hESCs) as a platform to study GATA6 function during early cardiogenesis. GATA6 loss-of-function hESCs had a profound impairment in cardiac progenitor cell (CPC) specification and cardiomyocyte (CM) generation due to early defects during the mesendoderm and lateral mesoderm patterning stages. Profiling by RNA-seq and CUT&RUN identified genes of the WNT and BMP programs regulated by GATA6 during early mesoderm patterning. Furthermore, interactome analysis detected GATA6 binding with developmental transcription factors and chromatin remodelers suggesting cooperative regulation of cardiac lineage gene accessibility. We show that modulating WNT and BMP inputs during the first 48 hours of cardiac differentiation is sufficient to partially rescue CPC and CM defects in GATA6 heterozygous and homozygous mutant hESCs. This study provides evidence of the regulatory functions for GATA6 directing human precardiac mesoderm patterning during the earliest stages of cardiogenesis to further our understanding of haploinsufficiency causing CHD and the co-occurrence of cardiac and other organ defects caused by human GATA6 mutations.

Sequence variations in GATA4 and CITED2 gene among patients with cardiac septation defects from Xinjiang, China.

Studies have shown that genetic factors play an important role in CHD's development. The mutations in GATA4 and CITED2 genes result in the failure of the heart to develop normally, thereby leading to septal defects. The present study investigated the underlying molecular aetiology of patients with cardiac septation defects from Xinjiang. We investigated variants of the GATA4 and CITED2 gene coding regions in 172 patients with cardiac septation defects by sequencing. Healthy controls (n = 200) were included. Three heterozygous variations (p.V380M, p.P394T, and p.P407Q) of the GATA4 gene were identified in three patients. p.V380M was discovered in a patient with atrial septal defect. p.P394T was noted in a patient with atrial septal defect. p.V380M and p.P407Q of the GATA4 gene were detected in one patient with ventricular septal defect. A novel homozygous variation (p. Sl92G) of the CITED2 gene was found in one patient with ventricular septal defect. Other patients and healthy individuals were normal. The limited prevalence of genetic variations observed in individuals with cardiac septal defects from Xinjiang provides evidence in favour of the hypothesis that CHD is a polygenic hereditary disorder. It is plausible that mutations in the GATA4 and CITED2 genes could potentially underlie the occurrence of idiopathic CHD in affected patients.

An Anterior Second Heart Field Enhancer Regulates the Gene Regulatory Network of the Cardiac Outflow Tract.

Conotruncal defects due to developmental abnormalities of the outflow tract (OFT) are an important cause of cyanotic congenital heart disease. Dysregulation of transcriptional programs tuned by NKX2-5 (NK2 homeobox 5), GATA6 (GATA binding protein 6), and TBX1 (T-box transcription factor 1) have been implicated in abnormal OFT morphogenesis. However, there remains no consensus on how these transcriptional programs function in a unified gene regulatory network within the OFT. We generated mice harboring a 226-nucleotide deletion of a highly conserved cardiac enhancer containing 2 GATA-binding sites located ≈9.4 kb upstream of the transcription start site of Nkx2-5 (Nkx2-5∆enh) using CRISPR-Cas9 gene editing and assessed phenotypes. Cardiac defects in Nkx2-5∆enh/∆enh mice were structurally characterized using histology and scanning electron microscopy, and physiologically assessed using electrocardiography, echocardiography, and optical mapping. Transcriptome analyses were performed using RNA sequencing and single-cell RNA sequencing data sets. Endogenous GATA6 interaction with and activity on the NKX2-5 enhancer was studied using chromatin immunoprecipitation sequencing and transposase-accessible chromatin sequencing in human induced pluripotent stem cell-derived cardiomyocytes. Nkx2-5∆enh/∆enh mice recapitulated cyanotic conotruncal defects seen in patients with NKX2-5, GATA6, and TBX1 mutations. Nkx2-5∆enh/∆enh mice also exhibited defects in right Purkinje fiber network formation, resulting in right bundle-branch block. Enhancer deletion reduced embryonic Nkx2-5 expression selectively in the right ventricle and OFT of mutant hearts, indicating that enhancer activity is localized to the anterior second heart field. Transcriptional profiling of the mutant OFT revealed downregulation of important genes involved in OFT rotation and septation, such as Tbx1, Pitx2, and Sema3c. Endogenous GATA6 interacted with the highly conserved enhancer in human induced pluripotent stem cell-derived cardiomyocytes and in wild-type mouse hearts. We found critical dose dependency of cardiac enhancer accessibility on GATA6 gene dosage in human induced pluripotent stem cell-derived cardiomyocytes. Our results using human and mouse models reveal an essential gene regulatory network of the OFT that requires an anterior second heart field enhancer to link GATA6 with NKX2-5-dependent rotation and septation gene programs.

PSUN285 Use of Continuous Glucose Monitoring in Managing Neonatal Diabetes in a Very Low Birth Weight Infant with a GATA-6 Mutation

Abstract Introduction Although continuous glucose monitoring (CGM) has increased in patients with Type 1 diabetes, its use in the neonatal population has remained limited. Neonates, particularly preterm infants, are at risk of impaired glucose control. Several studies have looked at the use of these devices in improving care for premature infants without diabetes. We describe a case of a very low birth infant with neonatal diabetes secondary to a GATA-6 mutation. Clinical Case This is a late preterm infant with IUGR, truncus arteriosus, and neonatal diabetes. Exome genetic panel showed a mutation in GATA-6. Her neonatal diabetes was challenging to control due to variable blood sugars and sensitivity to insulin. Weight gain remained poor. A CGM (Dexcom G6) was placed when the infant was 1.59kg to optimize her diabetes management and improve weight gain. An insulin titration chart was used to adjust her IV regular insulin infusion according to the CGM glucose levels and trend arrows. The following outcomes were reviewed and analyzed fourteen days before and after CGM placement: glucose levels (238 vs. 177 mg/dL), percentage of glucose levels within target range of 70-180mg/dL (31% vs 51%), average number of daily POC glucose checks (10.2 vs. 6.9), average amount of insulin received per day (0.42 vs 0.52 units/day), and average weight gain (11.4 vs. 20.7 grams/day). The discrepancy between POC and CGM glucose was also analyzed. CGM was within 20% of POC values 44% of the time and within 30% POC values 70% of the time. Adverse side effects of CGM were also noted. The patient was started on antibiotics following a small abscess identified underneath the CGM site. Bruising and skin breakdown were noted at the site, and the patient completed a course of antibiotics for the cutaneous infection. There were no other concerns of infection related to CGM for the first 2.5 months following CGM placement. Conclusion This case highlights that CGM can effectively be used to optimize glucose management in neonatal diabetes in a very low birth weight infant. However, the area where the CGM is placed needs to be monitored for signs of infection. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Transcriptome and genome sequencing investigating the molecular characteristics of patients with varicocele infertility.

The prevalence of varicoceles in male infertility is increasing; however, the exact mechanism is unknown, and no direct studies of varicose spermatic veins have been conducted. Three patients with varicocele infertility were included to explore the possible factors that cause varicocele infertility, and varicose and nearby normal veins were harvested by varicocelectomy. RNA sequencing was performed on six vascular samples, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the screened differential expressed genes which were validated by quantitative reverse transcription-polymerase chain reaction. The genomes of the patients were analysed using next-generation sequencing to screen for genetic factors behind varicocele infertility. 1171 genes were upregulated and 2772 were downregulated in varicose spermatic veins compared with those in normal veins. These genes were significantly enriched in the alcohol consumption pathway. HIST1H4C, HIST1H4F, HIST1H4K, TM9SF1, and TMEFF1 were significantly differentially expressed. The genomic results identified patients with mutations in CFTR, NANOS1, SRCAP, GATA4, GCM2, TUBB1, ALDH7A1, ANTXR1, and MAP3K1. In conclusion, our results indicated that Alcohol consumption may be a cause of varicoceles. Mutations in certain genes, such as CFTR, may be a cause of male infertility due to varicoceles.

Generation of an induced pluripotent stem cell line (MUSIi015-A) from a diabetic patient carrying mutations in ZYG11A (p.L475P) and GATA6 (p.E51K)

Two heterozygous mutations (p.L475P in ZYG11A and p.E51K in GATA6) were identified in a family with autosomal dominant diabetes. ZYG11A-p.L475P was proposed as a causative mutation because of the complete segregation with hyperglycemia and the proven pathogenic effect on beta-cell expansion. The modifying effect of GATA6-p.E51K was proposed owing to the earlier onset of the carriers. Herein, we establish a line of induced pluripotent stem cells (iPSCs) from peripheral blood mononuclear cells (PBMCs) of a proband who carries both mutations using Sendai viral vectors. The generated iPSC line was characterized for pluripotency, chromosomal normality, and authentication.

GATA6 amplification is associated with improved survival of TP53-mutated pancreatic cancer.

e16285 Background: Recent investigation in pancreatic adenocarcinoma (PDAC) demonstrates an association of molecular subtype with chemosensitivity and prognosis. TP53 and GATA6 are two genes independently associated with worse survival in PDAC. Here, we evaluated treatment outcome by genetic alterations of TP53 and GATA6 among patients with pancreatic cancer across New York’s largest health care system. Methods: This is a retrospective analysis of patients at Northwell Health diagnosed with PDAC between 2014 to 2021. Surgical status was used to segregate patients into two groups: resected and unresected. TP53 and GATA6 mutation status was compared for disease-free survival (DFS) (resected) or progression-free survival (PFS) (unresected), and for overall survival (OS). Additionally, patient survival by type of chemotherapy administered was evaluated. The Kaplan–Meier method was used to determine overall survival (OS), and the Wilcoxon test was used to compare survival curves. Results: Tumor mutational profiling data were available for 129 patients. TP53 mutations were found in 105 patients (81.4%), GATA6 amplifications were found in 18 patients (14.0%), and 16 patients had both mutations. TP53 mutations were associated with a worse OS compared to the wild-type TP53 population (n = 24) (median OS 22.7 months, 95% CI 12.5 to 41.1, vs. 44.3 months, 95% CI 24.5 to 80.3, HR 1.97, p = 0.048). Among patients with a TP53 mutation, a survival advantage was observed in those who had a GATA6 amplification compared to those who did not (median OS 25.5 months, 95% CI 10.9 to 44.6, vs. 22.1 months, 95% CI 12.6 to 51.5, HR 1.68, p = 0.038). In patients with unresected PDAC, the survival advantage of GATA6 amplification within TP53 mutated group was more prominent than the absence of the amplification (median OS 23.8 months, 95% CI 10.0 to 56.5, n = 12 vs. 10.5 months, 95% CI 4.4 to 24.8, n = 55, HR 0.52, p = 0.008). In the TP53 mutation group, among 33 patients who received Gem/NabP as the first-line chemotherapy, patients with GATA6 amplification (n = 8) had significantly improved survival compared to those without GATA6 amplification (n = 25) (mean OS 23.1 months, 95% CI 8.5 to 63.0, vs. 9.4 months, 95% CI 3.44 to 26.6, HR 0.51, p = 0.027). Conclusions: Genetic mutations in TP53 were associated with shorter OS than wild-type TP53. Contrary to our initial expectation that co-mutation would be associated with even worse survival, we found that GATA6 amplification appeared to attenuate poor prognosis observed in TP53-mutant patients. Additionally, GATA6 amplification may be a predictive marker for better responses to Gem/NabP chemotherapy.

The nuclear receptor ERR cooperates with the cardiogenic factor GATA4 to orchestrate cardiomyocyte maturation

Estrogen-related receptors (ERR) α and γ were shown recently to serve as regulators of cardiac maturation, yet the underlying mechanisms have not been delineated. Herein, we find that ERR signaling is necessary for induction of genes involved in mitochondrial and cardiac-specific contractile processes during human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) differentiation. Genomic interrogation studies demonstrate that ERRγ occupies many cardiomyocyte enhancers/super-enhancers, often co-localizing with the cardiogenic factor GATA4. ERRγ interacts with GATA4 to cooperatively activate transcription of targets involved in cardiomyocyte-specific processes such as contractile function, whereas ERRγ-mediated control of metabolic genes occurs independent of GATA4. Both mechanisms require the transcriptional coregulator PGC-1α. A disease-causing GATA4 mutation is shown to diminish PGC-1α/ERR/GATA4 cooperativity and expression of ERR target genes are downregulated in human heart failure samples suggesting that dysregulation of this circuitry may contribute to congenital and acquired forms of heart failure.

Novel Point Mutations in 3'-Untranslated Region of GATA4 Gene Are Associated with Sporadic Non-syndromic Atrial and Ventricular Septal Defects.

Transcription factor GATA4 has significant roles in embryonic heart development. Mutations of GATA4 appear to be responsible for a wide variety of congenital heart defects (CHD). Despite the high prevalence of GATA4 mutations in CHD phenotypes, extensive studies have not been performed. The 3'-untranslated region (3'-UTR) of the GATA4 gene comprises regulatory motifs and microRNA binding sites that are critical for the appropriate gene expression, nuclear transportation, and regulation of translation, and stability of mRNA. This study aimed to evaluate the association between mutations in the 3'-UTR of the GATA4 gene and CHD risk among Iranian patients. We analyzed the coding region of exon 6 and the whole 3'-UTR of GATA4 in DNA isolated from 175 blood samples of CHD patients and 115 unrelated healthy individuals. The functional importance of the observed GATA4 mutations was evaluated using a variety of bioinformatics algorithms for assessment of nonsynonymous mutations and those observed in miRNA binding sites of 3'-UTR. Twenty-one point mutations including one missense mutation (c.511A>G: p.Ser377Gly) in exon 6 and 20 nucleotide variations in 3'-UTR of GATA4 gene were identified in 65 of the 175 CHD patients. In our patients, we identified 12 novel sequence alterations and 8 single nucleotide polymorphisms in the 3'-UTR of GATA4. Most of them had statistically significant differences between CHD patients and controls. Our results suggest that 3'-UTR variations of the GATA4 gene probably change microRNA binding sites and present an additional molecular risk factor for the susceptibility of CHD.

Loss of GATA4 C-Terminus by p.S335X Mutation Modulates Coronary Artery Vascular Smooth Muscle Cell Phenotype.

Coronary artery disease (CAD) has been the leading cause of morbidity and mortality worldwide, and its pathogenesis is closely related with the proliferation and migration of vascular smooth muscle cell (VSMC). We previously reported a truncated GATA4 protein lacking C-terminus induced by p.S335X mutation in cardiomyocyte from ventricular septal defect (VSD) patients. However, it is still unclear whether GATA4 p.S335X mutation could influence the development of CAD. GATA4 wild-type (WT) and p.S335X mutant (MU) overexpression plasmids were constructed and transfected transiently into rat coronary artery smooth muscle cell (RCSMC) to observe the proliferative and migratory abilities by MTS and wound healing assay, respectively. PCR array was used to preliminarily detect the expression of phenotypic modulation-related genes, and QRT-PCR was then carried out to verify the screened differentially expressed genes (DEGs). The results showed that, when stimulated by fetal bovine serum (10%) for 24 h or tumor necrosis factor-α (10 or 30 ng/ml) for 10 or 24 h, deletion of GATA4 C-terminus by p.S335X mutation in GATA4 enhanced the proliferation of RCSMC, without alteration of the migration capability. Twelve DEGs, including Fas, Hbegf, Itga5, Aimp1, Cxcl1, Il15, Il2rg, Il7, Tnfsf10, Il1r1, Irak1, and Tlr3, were screened and identified as phenotypic modulation-related genes. Our data might be beneficial for further exploration regarding the mechanisms of GATA4 p.S335X mutation on the phenotypic modulation of coronary VSMC.

Comprehensive analysis of genomic alterations of Chinese hilar cholangiocarcinoma patients

Cholangiocarcinoma (CCA) is a rare malignant tumor of the biliary system. The heterogeneity of CCA leads to the lack of effective targeted treatment for CCA subtypes. The molecular characteristic of hilar CCA (hCCA) is still unclear. A total of 63 hCCA patients were enrolled from Shanghai Eastern Hepatobiliary Surgery Hospital. Formalin-fixed, paraffin-embedded tumor tissues, and matched blood were collected and deep sequencing targeting 450 cancer genes were performed. Tumor mutation burden(TMB) was measured by an algorithm developed in-house. Correlation analysis was performed by Fisher's exact test. The most commonly mutated genes were TP53 (51.7%), NF1 and KRAS (20%, for both), SMAD4 (16.7%), FAT3 and FRS2 (13.3%, for both), NF1 (11.7%), and KMT2C, MDM2, and ATM (10%, for each) in hCCA. ARID1A, GATA6, and PREX2 mutations commonly occurred in female and KMT2C mutations mainly occurred in patients under 60years old. Statistical analysis showed the association between ARID1A mutation and tumor stage (P = 0.041) and between NF1 mutation and high TMB (P = 0.0095). Furthermore, ARID1B mutation was identified to associate with the poor prognosis of Chinese hCCA patients (P = 0.004). The mutational characterization of hCCA is different from both extrahepatic CCA and intrahepatic CCA. ARID1B is a potential biomarker for prognosis prediction of Chinese hCCA patients.

Genome-wide analysis of primary microRNA expression using H3K36me3 ChIP-seq data

MicroRNAs are key players in gene regulatory networks controlling cell homeostasis. Their altered expression has been previously linked to disease outcomes and microRNAs thus serve as biomarkers for disease diagnostics. However, their synthesis and its transcriptional regulation have been challenging to investigate. In this study, we validated the use of H3K36me3 histone modification for the quantification of microRNA transcription levels using data from the ENCODE Consortium and then applied this approach to provide new insight into the cell-type-specific regulationin tissues, cell line models and cardiac disease. In cardiomyocytes derived from patients suffering from septal defects, carrying a G296S mutation in the transcription factor GATA4, we show that microRNA gene transcription is altered in cardiomyocytes carrying this mutation and coincides with novel super-enhancers formed within regulatory domains defined using chromatin interaction profiles. The most prominently elevated primary transcript encodes for let-7a and miR-100 that may target genes in the Hippo signaling pathway. Collectively, our work presents a methodology to quantify microRNA gene expression using histone marker data and paves the way for functional studies of cell-type-specific transcriptional regulation occurring in disease pathology.

GATA6 is a regulator of sinus node development and heart rhythm

The sinus node (SAN) is the primary pacemaker of the human heart, and abnormalities in its structure or function cause sick sinus syndrome, the most common reason for electronic pacemaker implantation. Here we report that transcription factor GATA6, whose mutations in humans are linked to arrhythmia, is highly expressed in the SAN and its haploinsufficiency in mice results in hypoplastic SANs and rhythm abnormalities. Cell-specific deletion reveals a requirement for GATA6 in various SAN lineages. Mechanistically, GATA6 directly activates key regulators of the SAN genetic program in conduction and nonconduction cells, such as TBX3 and EDN1, respectively. The data identify GATA6 as an important regulator of the SAN and provide a molecular basis for understanding the conduction abnormalities associated with GATA6 mutations in humans. They also suggest that GATA6 may be a potential modifier of the cardiac pacemaker.

Suppression of canonical TGF-β signaling enables GATA4 to interact with H3K27me3 demethylase JMJD3 to promote cardiomyogenesis

Direct reprogramming of fibroblasts into cardiomyocytes (CMs) represents a promising strategy to regenerate CMs lost after ischemic heart injury. Overexpression of GATA4, HAND2, MEF2C, TBX5, miR-1, and miR-133 (GHMT2m) along with transforming growth factor beta (TGF-β) inhibition efficiently promote reprogramming. However, the mechanisms by which TGF-β blockade promotes cardiac reprogramming remain unknown. Here, we identify interactions between the histone H3 lysine 27 trimethylation (H3K27me3) demethylase JMJD3, the SWI/SNF remodeling complex subunit BRG1, and cardiac transcription factors. Furthermore, canonical TGF-β signaling regulates the interaction between GATA4 and JMJD3. TGF-β activation impairs the ability of GATA4 to bind target genes and prevents demethylation of H3K27 at cardiac gene promoters during cardiac reprogramming. Finally, a mutation in GATA4 (V267M) that is associated with congenital heart disease exhibits reduced binding to JMJD3 and impairs cardiomyogenesis. Thus, we have identified an epigenetic mechanism wherein canonical TGF-β pathway activation impairs cardiac gene programming, in part by interfering with GATA4-JMJD3 interactions.

GATA6 mutations in hiPSCs inform mechanisms for maldevelopment of the heart, pancreas, and diaphragm.

Damaging GATA6 variants cause cardiac outflow tract defects, sometimes with pancreatic and diaphragmic malformations. To define molecular mechanisms for these diverse developmental defects, we studied transcriptional and epigenetic responses to GATA6 loss of function (LoF) and missense variants during cardiomyocyte differentiation of isogenic human induced pluripotent stem cells. We show that GATA6 is a pioneer factor in cardiac development, regulating SMYD1 that activates HAND2, and KDR that with HAND2 orchestrates outflow tract formation. LoF variants perturbed cardiac genes and also endoderm lineage genes that direct PDX1 expression and pancreatic development. Remarkably, an exon 4 GATA6 missense variant, highly associated with extra-cardiac malformations, caused ectopic pioneer activities, profoundly diminishing GATA4, FOXA1/2, and PDX1 expression and increasing normal retinoic acid signaling that promotes diaphragm development. These aberrant epigenetic and transcriptional signatures illuminate the molecular mechanisms for cardiovascular malformations, pancreas and diaphragm dysgenesis that arise in patients with distinct GATA6 variants.

SUN-074 Loss-Of-Function Mutations in GATA4 in Patients with 46,XY Disorders of Sex Development Without Cardiac Defects

Background: Disorders of sex development (DSD) encompass a wide range of conditions associated with numerous causative genes. In about 50-60% of 46,XY DSD individuals, the underlying molecular cause remains uncertain. GATA4 haploinsufficiency has been described in patients with congenital heart defects (CHD), while only a few studies reported mutations related to 46,XY DSD phenotype. This study investigated clinical phenotypes and molecular characteristics of two 46,XY DSD patients with GATA4 mutations. Methods: Mutation analysis was performed in patients with 46,XY DSD by whole exome sequencing (WES) using Illumina NextSeq platform. Clinical and endocrine characteristics were reviewed retrospectively. GATA4 variants identified by WES were verified by Sanger sequencing. Functional activity of GATA4 variants was tested by luciferase reporter assay on the SRY and AMH promoter using two different cell systems including HEK293 and NCI-H295R. Results: Subject 1 presented with micropenis and hypospadias at the age of 5 months. Karyotype was 46,XY. Mullerian duct remnants were not found in pelvic ultrasound. The patient underwent urethroplasty at the age of 10 months and was reared as a male. Subject 2 with complete female external genitalia was referred to our hospital because of 46,XY karyotype on G-scanning. The patient underwent laparoscopic orchiectomy at the age of 1.8 years and was assigned as a female. Both patients were responsive to hCG stimulation tests and did not have CHD. Subject 1 harbored a novel heterozygous variant of c.643A>G (p.R215G)] in GATA4, whereas a previously reported variant of c.1220C>A (p.P407Q) was identified in Subject 2. In vitro luciferase reporter assays using SRY and AMH promoter revealed decreased transcriptional activity of both p.P407Q and p.R215G. Conclusions: This study expanded phenotypic spectrum of mutations in GATA4 in patients with 46,XY DSD without CHD. GATA4 mutations in patients with 46,XY DSD may not be associated with CHD. Possible explanations for phenotypical variability comprise incomplete penetrance, variable expressivity, and oligogenic mechanisms.

A Nonsense GATA6 Mutation Explains History of Congenital Heart Defects and 10 Years of Poorly-Controlled Diabetes Lacking DKA in a Non-Obese 30 Year-Old Incidentally Found to Have Pancreatic Hypoplasia

To report a case of diabetes mellitus (DM) associated with partial pancreatic agenesis and congenital heart disease (CHD) in a patient found to have a nonsense mutation of the GATA6 gene. We present the imaging, laboratory, and genetic findings, and describe the clinical course of a patient with an atypical presentation of DM as well as CHD, who was found to have partial pancreatic agenesis on computed tomography (CT) imaging. Genetic testing was performed to identify monogenic DM. A 30-year-old nonobese female with a waxing and waning pattern of insulin-dependent DM diagnosed at the age of 20 was found to have partial pancreatic agenesis on CT scan. It was unclear whether the patient was experiencing undetected hyperglycemia prior to initial diagnosis of DM. She had no history of diabetic ketoacidosis (DKA) despite poorly-controlled diabetes and years without insulin treatment. The patient also had congenital tricuspid atresia, ventricular septal defect, and transposition of the great vessels with surgical correction in childhood. Partial pancreatic agenesis and CHD with atypical DM prompted genetic testing for monogenic DM, and a nonsense mutation of the GATA6 (c.1242C>A, p.C414*) gene was found. GATA6 mutations are associated with a broad spectrum of diabetic phenotypes, pancreatic agenesis, and a variety of CHDs. This case highlights the importance of considering monogenic diabetes in young, nonobese patients with diabetes, particularly with negative pancreatic antibodies and no history of DKA. Further, this case demonstrates the importance of testing for GATA6 mutations in any young patient with diabetes and CHD.

Case report: adult onset diabetes with partial pancreatic agenesis and congenital heart disease due to a de novo GATA6 mutation

BackgroundMutations in GATA6 are the most frequent cause of pancreatic agenesis. Most cases present with neonatal diabetes mellitus.Case presentationThe case was a female born after an uncomplicated pregnancy and delivery in a non-consanguineous family (3.59 kg, 70th percentile). Severe cardiac malformations were diagnosed at two and a half months old. No hyperglycaemic episodes were recorded in the neonatal period. Diabetes was diagnosed at 21 years due to the detection of incidental glycosuria. She had a low but detectable C-peptide level at diagnosis. Anti-GAD and Islet-cell antibodies were negative and she failed oral hypoglycaemic therapy and was started on insulin. Abdominal MRI revealed the absence of most of the neck, body, and tail of pancreas with normal pancreas elastase levels. Criteria for type 1 or type 2 diabetes were not fulfilled, therefore a next generation sequencing (NGS) panel was performed. A novel heterozygous pathogenic GATA6 mutation (p.Tyr235Ter) was identified. The GATA6 variant was not detected in her parents, implying that the mutation had arisen de novo in the proband.ConclusionRarely GATA6 mutations can cause adult onset diabetes. This report highlights the importance of screening the GATA6 gene in patients with adult-onset diabetes, congenital cardiac defects and pancreatic agenesis with no first-degree family history of diabetes. It also emphasizes the importance of genetic counselling in these patients as future offspring will be at risk of inheriting the variant and developing GATA6 anomalies.

Screening and functional analysis of GATA-6 mutations in patients with nonsyndromic conotruncal defects

Objective To explore the molecular and genetic mechanism of transcription factor GATA-6 in nonsyndromic conotruncal defect (CTD) in order to provide evidence for early prevention and inheritance consultation of CTD. Methods A total of 32 cases of patients with nonsyndromic CTD and 100 healthy individuals were enrolled in the study.A total of 7 exons and bilateral partial intron-exon boundaries of GATA-6 were amplified by means of polymerase chain reaction (PCR). The PCR products were purified and directly sequenced by using an ABI Genetic Analyzer 3100 Automatic DNA sequence equipment.The acquired GATA-6 gene sequence was compared with standard gene sequence published in National Center for Biotechnology Information database, as well as the healthy control group to observe the GATA-6 gene mutations.The mutations were introduced into pcDNA3.1(+ ) by site-directed mutagenesis PCR on the basis of pcDNA3.1(+ )-GATA-6 in order to generate the GATA6-G245R mutant constructs.Wild type GATA-6, GATA-6-G245R and atrial natriuretic factor-luciferase(ANF-luciferase) were cotransfected into HEK 293T cells in vitro, and the CMV-LacZ were cotransfected as internal reference.Luciferase and galactosidase activity were measured by using luminometer 24 h after transfection and detected in the downstream ANF-luciferase reporter gene. Results A heterozygous missense mutation in the GATA-6 gene was identified in a patient with double outlets of the right ventricle.The mutation was located in Gly245Arg(G245R) in exon 2 of GATA-6.The mutation of pcDNA3.1(+ )-GATA-6 expression vectors were successfully constructed.Through the detection of luciferase reporter gene activity, it was found that GATA-6-G245R and wild-type GATA-6 decreased by 41.3%, and the comparison between them was statistically significant (P<0.001). Conclusions Transcription factor GATA-6 gene mutation is associated with the occurrence of nonsyndromic CTD.Transcription factor GATA-6 gene may be susceptible gene in human nonsyndromic CTD. Key words: Nonsyndromic conotruncal defect; Transcription factor GATA-6; Mutation; Plasmid; Report gene