Not Only RET but NF1 and Chromosomal Instability Are Seen in Young Patients with Sporadic Medullary Thyroid Carcinoma.

Context: Genetic analysis of sporadic medullary thyroid carcinoma (MTC) has revealed somatic variants in RET, RAS, and occasionally other genes. However, around 20% of patients with sporadic MTC lack a known genetic driver. Objective: To uncover potential new somatic or germline drivers, we analyze a distinct cohort of patients with sporadic, very early-onset, and aggressive MTC. Methods: Germline and somatic DNA exome sequencing was performed in 19 patients, previously tested negative for germline RET variants. Results: Exome sequencing of 19 germline samples confirmed the absence of RET and identified an NF1 pathogenic variant in 1 patient. Somatic sequencing was successful in 15 tumors revealing RET variants in 80%, predominantly p.Met918Thr, which was associated with disease aggressiveness. In RET-negative tumors, pathogenic variants were found in HRAS and NF1. The NF1 germline and somatic variants were observed in a patient without a prior clinical diagnosis of neurofibromatosis type 1, demonstrating that the loss of heterozygosity of NF1 functions as a potential MTC driver. Somatic copy number alterations analysis revealed chromosomal alterations in 53.3% of tumors, predominantly in RET-positive cases, with losses in chromosomes 9 and 22 being the most prevalent. Conclusion: This study reveals that within a cohort of early-onset nonhereditary MTC, RET remains the major driver gene. In RET-negative tumors, NF1 and RAS are drivers of sporadic MTC. In addition, in young patients without a RET germline mutation, a careful clinical evaluation with a consideration of germline NF1 gene analysis is ideal to exclude Neurofibromatosis type 1 (NF1).

Exome Sequencing Identifies Multiple Genetic Diagnoses in Children with Syndromic Growth Disorders.

OBJECTIVE: To evaluate the presence of multiple genetic diagnoses in syndromic growth disorders. STUDY DESIGN: We carried out a cross-sectional study to evaluate 115 patients with syndromic tall (n = 24) or short stature (n = 91) of unknown cause from a tertiary referral center for growth disorders. Exome sequencing was performed to assess germline single nucleotide, InDel, and copy number variants. All variants were classified according to ACMG/AMP guidelines. The main outcome measured was the frequency of multiple genetic diagnoses in a cohort of children with syndromic growth disorders. RESULTS: The total diagnostic yield of the cohort was 54.8% (63/115). Six patients had multiple genetic diagnoses (tall stature group = 2; short stature group = 4). The proportion of multiple diagnoses within total cases was 5.2% (6/115), and within solved cases was 9.5% (6/63). No characteristics were significantly more frequent when compared with patients with single or multiple genetic findings. Among patients with multiple diagnoses, 3 had syndromes with overlapping clinical features, and the others had syndromes with distinct phenotypes. CONCLUSION: Recognition of multiple genetic diagnoses as a possibility in complex cases of syndromic growth disorders opens a new perspective on treatment and genetic counseling for affected patients, defying the medical common sense of trying to fit all findings into one diagnosis.

Effect of atorvastatin on muscle tissues of dermatomyositis and antisynthetase syndrome patients with dyslipidemia.

INTRODUCTION: In a recent study, we have shown that atorvastatin is clinically safe for dermatomyositis (DM) and antisynthetase syndrome (ASS) patients with dyslipidemia. Herein, we showed in an unprecedented way, the safety of atorvastatin on the muscular tissues of these patients. METHODS: Transcriptome analysis was performed on samples of the vastus lateralis muscle obtained at baseline and after 12 weeks of atorvastatin (20 mg/day) intervention in DM or ASS patients with dyslipidemia [6DM and 5ASS received atorvastatin, and 2DM and 3ASS received placebo]. The results were analyzed considering differences in expression fold change before and after treatment. Histological and histochemical analyses were also performed. RESULTS: In both groups, no significant changes were observed in genes related to the mitochondrial, oxidative, insulin, lipid, and fibrogenic pathways. Histological analysis showed a slight variability in the fiber size that was preserved after the intervention. In addition, the mosaic of muscle fibers was preserved in the internal architecture of the fibers and all histological regions. No fiber necrosis or atrophy, focal failures, subsarcolemmal accumulation, lipids, areas of fibrosis, or alterations in mitochondrial activity were observed. All muscle fibers were labeled for MHC I. CONCLUSION: Atorvastatin did not promote significant changes in the expression of genes related to mitochondrial, oxidative, insulin, lipid, and fibrogenic pathways in the muscle tissues of DM and ASS patients with dyslipidemia. Atorvastatin did not also promote histological and histochemical changes in muscle tissues. Our results reinforce the safety of the administration of atorvastatin to treat dyslipidemia in patients with DM and ASS.

Closing the loop on adrenal health, dysfunction, and disease.

A wearable microdialysis device measures ultradian patterns of adrenal hormone secretion in humans at minute scale (Upton et al.).

ß-Catenin-Driven Differentiation Is a Tissue-Specific Epigenetic Vulnerability in Adrenal Cancer.

Adrenocortical carcinoma (ACC) is a rare cancer in which tissue-specific differentiation is paradoxically associated with dismal outcomes. The differentiated ACC subtype CIMP-high is prevalent, incurable, and routinely fatal. CIMP-high ACC possess abnormal DNA methylation and frequent ß-catenin-activating mutations. Here, we demonstrated that ACC differentiation is maintained by a balance between nuclear, tissue-specific ß-catenin-containing complexes, and the epigenome. On chromatin, ß-catenin bound master adrenal transcription factor SF1 and hijacked the adrenocortical super-enhancer landscape to maintain differentiation in CIMP-high ACC; off chromatin, ß-catenin bound histone methyltransferase EZH2. SF1/ß-catenin and EZH2/ß-catenin complexes present in normal adrenals persisted through all phases of ACC evolution. Pharmacologic EZH2 inhibition in CIMP-high ACC expelled SF1/ß-catenin from chromatin and favored EZH2/ß-catenin assembly, erasing differentiation and restraining cancer growth in vitro and in vivo. These studies illustrate how tissue-specific programs shape oncogene selection, surreptitiously encoding targetable therapeutic vulnerabilities. SIGNIFICANCE: Oncogenic ß-catenin can use tissue-specific partners to regulate cellular differentiation programs that can be reversed by epigenetic therapies, identifying epigenetic control of differentiation as a viable target for ß-catenin-driven cancers.

GBM Cells Exhibit Susceptibility to Metformin Treatment According to TLR4 Pathway Activation and Metabolic and Antioxidant Status.

Glioblastoma (GBM) is an aggressive brain cancer associated with poor overall survival. The metabolic status and tumor microenvironment of GBM cells have been targeted to improve therapeutic strategies. TLR4 is an important innate immune receptor capable of recognizing pathogens and danger-associated molecules. We have previously demonstrated the presence of TLR4 in GBM tumors and the decreased viability of the GBM tumor cell line after lipopolysaccharide (LPS) (TLR4 agonist) stimulation. In the present study, metformin (MET) treatment, used in combination with temozolomide (TMZ) in two GBM cell lines (U87MG and A172) and stimulated with LPS was analyzed. MET is a drug widely used for the treatment of diabetes and has been repurposed for cancer treatment owing to its anti-proliferative and anti-inflammatory actions. The aim of the study was to investigate MET and LPS treatment in two GBM cell lines with different metabolic statuses. MET treatment led to mitochondrial respiration blunting and oxidative stress with superoxide production in both cell lines, more markedly in U87MG cells. Decreased cell viability after MET + TMZ and MET + LPS + TMZ treatment was observed in both cell lines. U87MG cells exhibited apoptosis after MET + LPS + TMZ treatment, promoting increased ER stress, unfolded protein response, and BLC2 downregulation. LPS stimulation of U87MG cells led to upregulation of SOD2 and genes related to the TLR4 signaling pathway, including IL1B and CXCL8. A172 cells attained upregulated antioxidant gene expression, particularly SOD1, TXN and PRDX1-5, while MET treatment led to cell-cycle arrest. In silico analysis of the TCGA-GBM-RNASeq dataset indicated that the glycolytic plurimetabolic (GPM)-GBM subtype had a transcriptomic profile which overlapped with U87MG cells, suggesting GBM cases exhibiting this metabolic background with an activated inflammatory TLR4 pathway may respond to MET treatment. For cases with upregulated CXCL8, coding for IL8 (a pro-angiogenic factor), combination treatment with an IL8 inhibitor may improve tumor growth control. The A172 cell line corresponded to the mitochondrial (MTC)-GBM subtype, where MET plus an antioxidant inhibitor, such as anti-SOD1, may be indicated as a combinatory therapy.

Diagnostic yield of a multigene sequencing approach in children classified as idiopathic short stature.

Objective: Most children with short stature remain without an etiologic diagnosis after extensive clinical and laboratory evaluation and are classified as idiopathic short stature (ISS). This study aimed to determine the diagnostic yield of a multigene analysis in children classified as ISS. Design and methods: We selected 102 children with ISS and performed the genetic analysis as part of the initial investigation. We developed customized targeted panel sequencing, including all genes already implicated in the isolated short-stature phenotype. Rare and deleterious single nucleotide or copy number variants were assessed by bioinformatic tools. Results: We identified 20 heterozygous pathogenic (P) or likely pathogenic (LP) genetic variants in 17 of 102 patients (diagnostic yield = 16.7%). Three patients had more than one P/LP genetic alteration. Most of the findings were in genes associated with the growth plate differentiation: IHH (n = 4), SHOX (n = 3), FGFR3 (n = 2), NPR2 (n = 2), ACAN (n = 2), and COL2A1 (n = 1) or involved in the RAS/MAPK pathway: NF1 (n = 2), PTPN11 (n = 1), CBL (n = 1), and BRAF (n = 1). None of these patients had clinical findings to guide a candidate gene approach. The diagnostic yield was higher among children with severe short stature (35% vs 12.2% for height SDS ≤ or > -3; P = 0.034). The genetic diagnosis had an impact on clinical management for four children. Conclusion: A multigene sequencing approach can determine the genetic etiology of short stature in up to one in six children with ISS, removing the term idiopathic from their clinical classification.

High frequency of genetic/epigenetic disorders in short stature children born with very low birth weight.

Most infants born with very low birth weight (VLBW, birth weight < 1500 g) show spontaneous catch-up growth in postnatal life. The reasons for the absence of catch-up growth are not entirely understood. We performed a comprehensive investigation of 52 children born with VLBW. Ten children had a history of an external cause that explained the VLBW and five refused genetic evaluation. Twenty-three cases were initially evaluated by a candidate gene approach. Patients with a negative result in the candidate gene approach (n = 14) or without clinical suspicion (n = 14) were assessed by chromosome microarray analysis (CMA) and/or whole-exome sequencing (WES). A genetic condition was identified in 19 of 37 (51.4%) patients without an external cause, nine by candidate gene approach, and 10 by a genomic approach (CMA/WES). Silver-Russell syndrome was the most frequent diagnosis (n = 5) and the remaining patients were diagnosed with other rare monogenic conditions. Almost all patients with a positive genetic diagnosis exhibited syndromic features (94.4%). However, microcephaly, neurodevelopmental disorders, major malformation, or facial dysmorphism were also frequently observed in children with an external cause. In conclusion, a significant proportion of children born with VLBW with persistent short stature have a genetic/epigenetic condition.

Update on Biology and Genomics of Adrenocortical Carcinomas: Rationale for Emerging Therapies.

The adrenal glands are paired endocrine organs that produce steroid hormones and catecholamines required for life. Adrenocortical carcinoma (ACC) is a rare and often fatal cancer of the peripheral domain of the gland, the adrenal cortex. Recent research in adrenal development, homeostasis, and disease have refined our understanding of the cellular and molecular programs controlling cortical growth and renewal, uncovering crucial clues into how physiologic programs are hijacked in early and late stages of malignant neoplasia. Alongside these studies, genome-wide approaches to examine adrenocortical tumors have transformed our understanding of ACC biology, and revealed that ACC is composed of distinct molecular subtypes associated with favorable, intermediate, and dismal clinical outcomes. The homogeneous transcriptional and epigenetic programs prevailing in each ACC subtype suggest likely susceptibility to any of a plethora of existing and novel targeted agents, with the caveat that therapeutic response may ultimately be limited by cancer cell plasticity. Despite enormous biomedical research advances in the last decade, the only potentially curative therapy for ACC to date is primary surgical resection, and up to 75% of patients will develop metastatic disease refractory to standard-of-care adjuvant mitotane and cytotoxic chemotherapy. A comprehensive, integrated, and current bench-to-bedside understanding of our field's investigations into adrenocortical physiology and neoplasia is crucial to developing novel clinical tools and approaches to equip the one-in-a-million patient fighting this devastating disease.

Contribution of Clinical and Genetic Approaches for Diagnosing 209 Index Cases With 46,XY Differences of Sex Development.

CONTEXT: Massively parallel sequencing (MPS) technologies have emerged as a first-tier approach for diagnosing several pediatric genetic syndromes. However, MPS has not been systematically integrated into the diagnostic workflow along with clinical/biochemical data for diagnosing 46,XY differences of sex development (DSD). OBJECTIVE: To analyze the contribution of phenotypic classification either alone or in association with genetic evaluations, mainly MPS, for diagnosing a large cohort of 46,XY DSD patients. DESIGN/PATIENTS: 209 nonsyndromic 46,XY DSD index cases from a Brazilian DSD center were included. Patients were initially classified into 3 subgroups according to clinical and biochemical data: gonadal dysgenesis (GD), disorders of androgen secretion/action, and DSD of unknown etiology. Molecular genetic studies were performed by Sanger sequencing and/or MPS. RESULTS: Clinical/biochemical classification into either GD or disorders of hormone secretion/action was obtained in 68.4% of the index cases. Among these, a molecular diagnosis was obtained in 36% and 96.5%, respectively. For the remainder 31.6% classified as DSD of clinically unknown etiology, a molecular diagnosis was achieved in 31.8%. Overall, the molecular diagnosis was achieved in 59.3% of the cohort. The combination of clinical/biochemical and molecular approaches diagnosed 78.9% of the patients. Clinical/biochemical classification matched with the genetic diagnosis in all except 1 case. DHX37 and NR5A1 variants were the most frequent genetic causes among patients with GD and DSD of clinical unknown etiology, respectively. CONCLUSIONS: The combination of clinical/biochemical with genetic approaches significantly improved the diagnosis of 46,XY DSD. MPS potentially decreases the complexity of the diagnostic workup as a first-line approach for diagnosing 46,XY DSD.

Glutaminolysis dynamics during astrocytoma progression correlates with tumor aggressiveness.

BACKGROUND: Glioblastoma is the most frequent and high-grade adult malignant central nervous system tumor. The prognosis is still poor despite the use of combined therapy involving maximal surgical resection, radiotherapy, and chemotherapy. Metabolic reprogramming currently is recognized as one of the hallmarks of cancer. Glutamine metabolism through glutaminolysis has been associated with tumor cell maintenance and survival, and with antioxidative stress through glutathione (GSH) synthesis. METHODS: In the present study, we analyzed the glutaminolysis-related gene expression levels in our cohort of 153 astrocytomas of different malignant grades and 22 non-neoplastic brain samples through qRT-PCR. Additionally, we investigated the protein expression profile of the key regulator of glutaminolysis (GLS), glutamate dehydrogenase (GLUD1), and glutamate pyruvate transaminase (GPT2) in these samples. We also investigated the glutathione synthase (GS) protein profile and the GSH levels in different grades of astrocytomas. The differential gene expressions were validated in silico on the TCGA database. RESULTS: We found an increase of glutaminase isoform 2 gene (GLSiso2) expression in all grades of astrocytoma compared to non-neoplastic brain tissue, with a gradual expression increment in parallel to malignancy. Genes coding for GLUD1 and GPT2 expression levels varied according to the grade of malignancy, being downregulated in glioblastoma, and upregulated in lower grades of astrocytoma (AGII-AGIII). Significant low GLUD1 and GPT2 protein levels were observed in the mesenchymal subtype of GBM. CONCLUSIONS: In glioblastoma, particularly in the mesenchymal subtype, the downregulation of both genes and proteins (GLUD1 and GPT2) increases the source of glutamate for GSH synthesis and enhances tumor cell fitness due to increased antioxidative capacity. In contrast, in lower-grade astrocytoma, mainly in those harboring the IDH1 mutation, the gene expression profile indicates that tumor cells might be sensitized to oxidative stress due to reduced GSH synthesis. The measurement of GLUD1 and GPT2 metabolic substrates, ammonia, and alanine, by noninvasive MR spectroscopy, may potentially allow the identification of IDH1mut AGII and AGIII progression towards secondary GBM.

APOL1 in an ethnically diverse pediatric population with nephrotic syndrome: implications in focal segmental glomerulosclerosis and other diagnoses.

BACKGROUND: APOL1 high-risk genotypes (HRG) are associated with increased risk of kidney disease in individuals of African ancestry. We analyzed the effects of APOL1 risk variants on an ethnically diverse Brazilian pediatric nephrotic syndrome (NS) cohort. METHODS: Multicenter study including 318 NS patients, categorized as progressors to advanced CKD [estimated glomerular filtration rate (eGFR)] < 30 mL/min/1.73 m2] and slow/non-progressors (eGFR > 30 mL/min/1.73 m2 through the study). We employed Cox regression with progression time as the outcome and APOL1 genotype as the independent variable. We tested this association in the entire cohort and three subgroups; (1) focal segmental glomerulosclerosis (FSGS), (2) steroid-resistant NS (SRNS), and (3) those who underwent kidney biopsy. RESULTS: Nineteen patients (6%) had an HRG. Of these, 47% were self-reported White. Patients with HRG manifested NS at older ages and presented higher frequencies of FSGS and SRNS. HRG patients progressed to advanced CKD more often than low-risk-genotype (LRG) children in the whole NS cohort (p = 0.001) and the three subgroups. In SRNS and biopsied patients, a single risk variant was associated with trends of higher CKD progression risk. CONCLUSIONS: Novel discoveries include a substantial prevalence of HRG among patients self-reported White, worse kidney outcomes in HRG versus LRG children in the FSGS subgroup, and a trend of higher CKD progression risk associated with a single risk variant in the SRNS cohort. These findings suggest APOL1-associated NS extends beyond patients self-reported non-White, the HRG effect is independent of FSGS, and a single risk variant may have a detrimental impact in children with NS.

Role of the Mevalonate Pathway in Adrenocortical Tumorigenesis.

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is the rate-limiting enzyme of the mevalonate pathway, which generates cholesterol and non-sterol compounds such as isoprenoid, which are involved in key steps of tumorigenesis such as cell growth and proliferation. Our aim was to evaluate the role of the mevalonate pathway in adrenocortical tumors (ACTs). Expression pattern of HMGCR, FDFT1, LDLR, SCARB1, StAR, TSPO, CYP11A1, CYP11B1, CYP17A1, CYP21A1, and HSD3B1 genes, involved in the mevalonate pathway and steroidogenesis, was quantified by real-time RT-PCR in 46 ACT [14 adenomas (ACA) and 11 carcinomas (ACC) from adults and 13 ACA and 8 ACC from pediatric patients]. Effects of the mevalonate pathway inhibition on NCI-H295A cell viability was assessed by colorimetric assay. HMGCR was overexpressed in most adult ACT. The expression of TSPO, STAR, CYP11B1, CYP21A1, and HSD3B1 in adult ACC was significantly lower than in ACA (p<0.05). Regarding pediatric ACT, the expression of genes involved in steroidogenesis was not different between ACA and ACC. Inhibition of isoprenoid production significantly decreased the viability of NCI-H295A cells (p<0.05). However, cholesterol synthesis blockage did not show the same effect on cell viability. Low expression of TSPO ,: StAR, CYP11B1, CYP21A1, and HSD3B1 characterized a signature of adult ACCs. Our data suggest that HMGCR overexpression in adult ACC might lead to intracellular isoprenoid accumulation and cell proliferation. Therefore, the mevalonate pathway is a potential target for ACC treatment.

Molecular profile of Hürthle cell carcinomas: recurrent mutations in the Wnt/ß-catenin pathway.

OBJECTIVE: Genomic alterations in Hürthle cell carcinomas (HCC) include chromosomal losses, mitochondrial DNA mutations, and changes in the expression profile of the PI3K-AKT-mTOR and Wnt/ß-catenin pathways. This study aimed at characterizing the mutational profile of HCC. METHODS: Next-generation sequencing (NGS) of 40 HCC using a 102-gene panel including, among others, the MAPK, PI3K-AKT-mTOR, Wnt/ß-catenin, and Notch pathways. HCC was widely invasive in 57.5%, and lymph node and distant metastases were diagnosed in 5% and 7.5% of cases. During follow-up, 10% of patients presented with persistent/recurrent disease, but there were no cancer-related deaths. RESULTS: Genetic alterations were identified in 47.5% of HCC and comprised 190 single-nucleotide variants and 5 insertions/deletions. The Wnt/ß-catenin pathway was most frequently affected (30%), followed by MAPK (27.5%) and PI3K-AKT-mTOR (25%). FAT1 and APC were the most frequently mutated genes and present in 17.5%. RAS mutations were present in 12.5% but no BRAF mutation was found. There was no association between the mutational profile and clinicopathological features. CONCLUSIONS: This series of HCC presents a wide range of mutations in the Wnt/ß-catenin, MAPK and PI3K-AKT-mTOR pathways. The recurrent involvement of Wnt/ß-catenin pathway, particularly mutations in APC and FAT1, are of particular interest. The data suggest that mutated FAT1 may represent a potential novel driver in HCC tumorigenesis and that the Wnt/ß-catenin pathway plays a critical role in this distinct thyroid malignancy.

SELAdb: A database of exonic variants in a Brazilian population referred to a quaternary medical center in São Paulo.

OBJECTIVES: High-throughput sequencing of genomes, exomes, and disease-focused gene panels is becoming increasingly common for molecular diagnostics. However, identifying a single clinically relevant pathogenic variant among thousands of genetic polymorphisms is a challenging task. Publicly available genomic databases are useful resources to filter out common genetic variants present in the population and enable the identification of each disease-causing variant. Based on our experience applying these technologies at Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), São Paulo, Brazil, we recognized that the Brazilian population is not adequately represented in widely available genomic databases. METHODS: Here, we took advantage of our 5-year experience as a high-throughput sequencing core facility focused on individuals with putative genetic disorders to build a genomic database that may serve as a more accurate reference for our patient population: SELAdb. RESULTS/CONCLUSIONS: Currently, our database comprises a final cohort of 523 unrelated individuals, including patients or family members managed by different clinics of HCFMUSP. We compared SELAdb with other publicly available genomic databases and demonstrated that this population is very heterogeneous, largely resembling Latin American individuals of mixed origin, rather than individuals of pure European ancestry. Interestingly, exclusively through SELAdb, we identified a spectrum of known and potentially novel pathogenic variants in genes associated with highly penetrant Mendelian disorders, illustrating that pathogenic variants circulating in the Brazilian population that is treated in our clinics are underrepresented in other population databases. SELAdb is freely available for public consultation at: http://intranet.fm.usp.br/sela.

High Prevalence of Alterations in DNA Mismatch Repair Genes of Lynch Syndrome in Pediatric Patients with Adrenocortical Tumors Carrying a Germline Mutation on TP53.

Adrenocortical cancer is a rare malignant neoplasm associated with a dismal prognosis. Identification of the molecular pathways involved in adrenal tumorigenesis is essential for a better understanding of the disease mechanism and improvement of its treatment. The aim of this study is to define the prevalence of alterations in DNA mismatch repair (MMR) genes in Lynch syndrome among pediatric patients with adrenocortical neoplasia from southern Brazil, where the prevalence of a specific TP53 germline mutation (p.Arg337His) is quite high. Thirty-six pediatric patients were retrospectively evaluated. Immunohistochemistry (IHC) for the MMR enzymes MLH1, MSH2, MSH6, and PMS2, as well as next-generation sequencing (NGS) were performed. For IHC, 36 pediatric tumors were tested. In all of them, the expression of all evaluated MMR proteins was well-preserved. For NGS, 35 patients with pediatric tumor were tested. Three patients (8.57%) with the TP53 p.Arg337His germline mutation presented pathogenic and likely pathogenic variants in the MMR genes (two in MLH1 and one in MSH6). The prevalence of altered MMR genes among pediatric patients was elevated (8.57%) and higher than in colorectal and endometrial cancer cohorts. Pediatric patients with adrenocortical tumors should, thus, be strongly considered as at genetic risk for Lynch syndrome.

Molecular and Electrophysiological Analyses of ATP2B4 Gene Variants in Bilateral Adrenal Hyperaldosteronism.

Primary aldosteronism (PA) is the most common cause of secondary hypertension with a high prevalence among patients with resistant hypertension. Despite the recent discovery of somatic variants in aldosterone-producing adenoma (APA)-associated PA, causes for PA due to bilateral aldosterone production (bilateral hyperaldosteronism; BHA) remain unknown. Herein, we identified rare gene variants in ATP2B4, in a cohort of patients with BHA. ATP2B4 belongs to the same family of Ca-ATPases as ATP2B3, which is involved in the pathogenesis of APA. Endogenous ATP2B4 expression was characterized in adrenal tissue, and the gene variants were functionally analyzed for effects on aldosterone synthase (CYP11B2) expression, steroid production in basal and agonist-stimulated conditions, and for changes in biophysical properties of channel properties. Knockdown of ATP2B4 in HAC15 exhibited reduced angiotensin II stimulation in one of four shRNA clones. Stable HAC15 cell lines with doxycycline (dox) - inducible wild-type and variant forms of ATP2B4 - were generated, and dox-induced upregulation of ATP2B4 mRNA and protein was confirmed. However, ATP2B4 variants did not alter basal or agonist-stimulated CYP11B2 expression. Whole-cell recordings in HAC15 cells indicated robust endogenous ATP2B4 conductance in native cells but reduced conductance with overexpressed WT and variant ATP2B4. The previously defined PA-causing ATP2B3 variant served as a positive control and exhibited elevated CYP11B2 mRNA. In conclusion, while this study did not confirm a pathogenic role for ATP2B4 variants in BHA, we describe the sequencing analysis for familial and sporadic BHA and outline a template for the thorough in vitro characterization of gene variants.

Clinical and Genetic Characterization of a Constitutional Delay of Growth and Puberty Cohort.

INTRODUCTION: Constitutional delay of growth and puberty (CDGP) is the most prevalent cause of delayed puberty in both sexes. Family history of delayed puberty (2 or more affected members in a family) has been evidenced in 50-75% of patients with CDGP and the inheritance is often consistent with autosomal dominant pattern, with or without complete penetrance. However, the molecular basis of CDGP is not completely understood. OBJECTIVE: To characterize the clinical and genetic features of a CDGP cohort. METHODS: Fifty-nine patients with CDGP (48 boys and 11 girls) underwent careful and long-term clinical evaluation. Genetic analysis was performed using a custom DNA target enrichment panel designed to capture 36 known and candidate genes implicated with pubertal development. RESULTS: All patients had spontaneous or induced pubertal development (transient hormonal therapy) prior to 18 years of age. The mean clinical follow-up time was 46 ± 28 months. Male predominance (81%), short stature (91%), and family history of delayed puberty (59%) were the main clinical features of this CDGP -cohort. Genetic analyses revealed 15 rare heterozygous missense variants in 15 patients with CDGP (25%) in seven different genes (IGSF10, GHSR, CHD7, SPRY4, WDR11, SEMA3A,and IL17RD). IGSF10 and GHSR were the most prevalent affected genes in this group. CONCLUSIONS: Several rare dominant variants in genes implicated with GnRH migration and metabolism were identified in a quarter of the patients with familial or sporadic CDGP, suggesting genetic heterogeneity in this frequent pediatric condition.

Genetic investigation of patients with tall stature.

CONTEXT: Patients with tall stature often remain undiagnosed after clinical investigation and few studies have genetically assessed this group, most of them without a systematic approach. OBJECTIVE: To assess prospectively a group of individuals with tall stature, with and without syndromic features, and to establish a molecular diagnosis for their growth disorder. DESIGN: Screening by karyotype (n = 42), chromosome microarray analyses (CMA) (n = 16), MS-MLPA (n = 2) targeted panel (n = 12) and whole-exome sequencing (n = 31). PATIENTS AND METHODS: We selected 42 patients with tall stature after exclusion of pathologies in GH/IGF1 axis and divided them into syndromic (n = 30) and non-syndromic (n = 12) subgroups. MAIN OUTCOME MEASURES: Frequencies of pathogenic findings. RESULTS: We identified two patients with chromosomal abnormalities including SHOX trisomy by karyotype, one 9q22.3 microdeletion syndrome by CMA, two cases of Beckwith-Wiedemann syndrome by targeted MS-MLPA analysis and nine cases with heterozygous pathogenic or likely pathogenic genetic variants by multigene analysis techniques (FBN1 = 3, NSD1 = 2, NFIX = 1, SUZ12 = 1, CHD8 = 1, MC4R = 1). Three of 20 patients analyzed by WES had their diagnosis established. Only one non-syndromic patient had a definitive diagnosis. The sequential genetic assessment diagnosed 14 out of 42 (33.3%) tall patients. CONCLUSION: A systematic molecular approach of patients with tall stature was able to identify the etiology in 13 out of 30 (43.3%) syndromic and 1 out of 12 (8.3%) non-syndromic patients, contributing to the genetic counseling and avoiding unfavorable outcomes in the syndromic subgroup.

SELAdb: A database of exonic variants in a Brazilian population referred to a quaternary medical center in São Paulo

OBJECTIVES: High-throughput sequencing of genomes, exomes, and disease-focused gene panels is becoming increasingly common for molecular diagnostics. However, identifying a single clinically relevant pathogenic variant among thousands of genetic polymorphisms is a challenging task. Publicly available genomic databases are useful resources to filter out common genetic variants present in the population and enable the identification of each disease-causing variant. Based on our experience applying these technologies at Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), São Paulo, Brazil, we recognized that the Brazilian population is not adequately represented in widely available genomic databases. METHODS: Here, we took advantage of our 5-year experience as a high-throughput sequencing core facility focused on individuals with putative genetic disorders to build a genomic database that may serve as a more accurate reference for our patient population: SELAdb. RESULTS/CONCLUSIONS: Currently, our database comprises a final cohort of 523 unrelated individuals, including patients or family members managed by different clinics of HCFMUSP. We compared SELAdb with other publicly available genomic databases and demonstrated that this population is very heterogeneous, largely resembling Latin American individuals of mixed origin, rather than individuals of pure European ancestry. Interestingly, exclusively through SELAdb, we identified a spectrum of known and potentially novel pathogenic variants in genes associated with highly penetrant Mendelian disorders, illustrating that pathogenic variants circulating in the Brazilian population that is treated in our clinics are underrepresented in other population databases. SELAdb is freely available for public consultation at: http://intranet.fm.usp.br/sela