Intraoperative radiofrequency ablation for unresectable abdominal paraganglioma: a case report.

For pheochromocytoma and paraganglioma (PPGL), the efficacy of percutaneous ablative therapies in achieving control of metastatic tumors measuring <3 cm had been demonstrated in only few reports, and intraoperative radiofrequency ablation (RFA) of locally invasive primary PPGLs has not been reported. We presented the case of a 31-year-old man who had a 9-cm functioning unresectable PPGL. He was treated with 13 cycles of cytotoxic chemotherapy without objective tumor response, according to the Response Evaluation Criteria in Solid Tumors (RECIST). Subsequently, magnetic resonance imaging revealed a 9.0 × 8.6 × 6.0-cm retroperitoneal mass that extended to the inferior portion of the inferior vena cava, the inferior mesenteric artery, and the infrarenal aorta. Biochemical evaluation demonstrated high level of plasma normetanephrine (20.2 nmol/L, normal range <0.9 nmol/L). Genetic investigation showed the germline pathogenic variant c.1591delC (p. Ser198Alafs*22) in the SDHB gene. I131-metaiodobenzylguanidine scintigraphy was negative and Ga68-dotatate PET-CT scan showed high tumor uptake without distant metastases. On open laparotomy, tumor debulking was not possible. Therefore, intraoperative RFA was performed by a highly experienced team of interventional radiologists. At 12 months after the RFA, the tumor volume decreased from 208 to 45 mL (78%), plasma normetanephrine decreased from 20.2 to 2.6 nmol/L (87%), and the doxazosin dose was reduced from 16 to 8 mg/day. To our best knowledge, this was the first report on intraoperative RFA that markedly reduced the size of a large primary unresectable PPGL, along with clinical and biochemical responses.

Clinical and Pathological Predictors of Death for Adrenocortical Carcinoma.

Adrenocortical carcinoma (ACC) is a rare and lethal disease with a poor prognosis. This study aims to share our 41-year experience as a referral center, focusing on identifying risk factors associated with ACC mortality. Our retrospective analysis included a cohort of 150 adult patients with ACC in all stage categories, treated between 1981 and 2022. Tumor hormonal hypersecretion was observed in 78.6% of the patients, and the median age of diagnosis was 40 years. The majority presented as European Network for the Study of Adrenal Tumors (ENSAT) III or IV (22.9% and 31.2%, respectively), and the overall mortality rate was 54.6%. Independent predictors of death were elevated secretion of cortisol (HR = 2.0), androstenedione (HR = 2.2), estradiol (HR = 2.8), 17-OH progesterone (HR = 2.0), and 11-deoxycortisol (HR = 5.1), higher Weiss (HR = 4.3), modified Weiss (HR = 4.4), and Helsinki scores (HR = 12.0), advanced ENSAT stage (HR = 27.1), larger tumor size (HR = 2.7), higher Ki-67 percentage (HR = 2.3), and incomplete surgical resection (HR = 2.5). Mitosis greater than 5/50 high-power field (HR = 5.6), atypical mitosis (HR = 2.3), confluent necrosis (HR = 15.4), venous invasion (HR = 2.8), and capsular invasion (HR = 2.4) were also identified as independent predictors of death. Knowing the risk factors for ACC's mortality may help determine the best treatment option.

Renal Function Evolution and Hypoaldosteronism Risk After Unilateral Adrenalectomy for Primary Aldosteronism.

Few studies demonstrated a percentage decrease in the estimated glomerular filtration rate (eGFR) at a single time and the rate of hypoaldosteronism after adrenalectomy for primary aldosteronism (PA). Our aim was to investigate the evolution of renal function and the hypoaldosteronism risk after adrenalectomy for PA. Aldosterone, renin, eGFR, and electrolyte levels were determined before and at 1 week, 1, 3 and 6 months after unilateral adrenalectomy in 94 PA patients (40 men and 54 women). The main outcome was the postoperative eGFR decline using analysis of covariance with the preoperative eGFR as a covariate. eGFR decreased during first postoperative week compared to 3 months before surgery. During the first 6 months, eGFR remained stable at similar levels to the first week after surgery. Age (p=0.001), aldosterone levels (p=0.021) and eGFR 3 months before surgery (p+<+0.0001) had a significant correlation with eGFR during first postoperative week. High aldosterone levels at diagnosis were correlated with decline in renal function in the univariate model (p=0.033). In the multivariate analysis, aldosterone levels at diagnosis had a tendency to be an independent predictor of renal function after surgery (p=0.059). Postoperative biochemical hypoaldosteronism was diagnosed in 48% of the cases after adrenalectomy, but prolonged hyperkalemia occurred in only 4 cases (4.5%). Our findings showed a decrease of eGFR after unilateral adrenalectomy for PA. Additionally, aldosterone levels at diagnosis correlated with postoperative renal function. Postoperative biochemical hypoaldosteronism occurred in almost half of the patients, but prolonged hyperkalemia with fludrocortisone replacement was less frequent.

Rare variants in the MECP2 gene in girls with central precocious puberty: a translational cohort study.

BACKGROUND: Identification of genetic causes of central precocious puberty have revealed epigenetic mechanisms as regulators of human pubertal timing. MECP2, an X-linked gene, encodes a chromatin-associated protein with a role in gene transcription. MECP2 loss-of-function mutations usually cause Rett syndrome, a severe neurodevelopmental disorder. Early pubertal development has been shown in several patients with Rett syndrome. The aim of this study was to explore whether MECP2 variants are associated with an idiopathic central precocious puberty phenotype. METHODS: In this translational cohort study, participants were recruited from seven tertiary centres from five countries (Brazil, Spain, France, the USA, and the UK). Patients with idiopathic central precocious puberty were investigated for rare potentially damaging variants in the MECP2 gene, to assess whether MECP2 might contribute to the cause of central precocious puberty. Inclusion criteria were the development of progressive pubertal signs (Tanner stage 2) before the age of 8 years in girls and 9 years in boys and basal or GnRH-stimulated LH pubertal concentrations. Exclusion criteria were the diagnosis of peripheral precocious puberty and the presence of any recognised cause of central precocious puberty (CNS lesions, known monogenic causes, genetic syndromes, or early exposure to sex steroids). All patients included were followed up at the outpatient clinics of participating academic centres. We used high-throughput sequencing in 133 patients and Sanger sequencing of MECP2 in an additional 271 patients. Hypothalamic expression of Mecp2 and colocalisation with GnRH neurons were determined in mice to show expression of Mecp2 in key nuclei related to pubertal timing regulation. FINDINGS: Between Jun 15, 2020, and Jun 15, 2022, 404 patients with idiopathic central precocious puberty (383 [95%] girls and 21 [5%] boys; 261 [65%] sporadic cases and 143 [35%] familial cases from 134 unrelated families) were enrolled and assessed. We identified three rare heterozygous likely damaging coding variants in MECP2 in five girls: a de novo missense variant (Arg97Cys) in two monozygotic twin sisters with central precocious puberty and microcephaly; a de novo missense variant (Ser176Arg) in one girl with sporadic central precocious puberty, obesity, and autism; and an insertion (Ala6_Ala8dup) in two unrelated girls with sporadic central precocious puberty. Additionally, we identified one rare heterozygous 3'UTR MECP2 insertion (36_37insT) in two unrelated girls with sporadic central precocious puberty. None of them manifested Rett syndrome. Mecp2 protein colocalised with GnRH expression in hypothalamic nuclei responsible for GnRH regulation in mice. INTERPRETATION: We identified rare MECP2 variants in girls with central precocious puberty, with or without mild neurodevelopmental abnormalities. MECP2 might have a role in the hypothalamic control of human pubertal timing, adding to the evidence of involvement of epigenetic and genetic mechanisms in this crucial biological process. FUNDING: Fundação de Amparo à Pesquisa do Estado de São Paulo, Conselho Nacional de Desenvolvimento Científico e Tecnológico, and the Wellcome Trust.

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.

SIN3A Defects Associated with Syndromic Congenital Hypogonadotropic Hypogonadism: An Overlap with Witteveen-Kolk Syndrome.

INTRODUCTION: Congenital hypogonadotropic hypogonadism (CHH) is a rare condition caused by GnRH deficiency. More than 40 genes have been associated with the pathogenesis of CHH, but most cases still remain without a molecular diagnosis. Mutations involving the same gene (e.g., FGFR1, PROK2/PROKR2, CHD7) were found to cause normosmic CHH and Kallmann syndrome (KS), with and without associated phenotypes, illustrating the coexistence of CHH with signs of other complex syndromes. The Witteveen-Kolk syndrome (WITKOS), caused by defects of the SIN3A gene, is a heterogeneous disorder characterized by distinctive facial features, microcephaly, short stature, delayed cognitive, and motor development. Although micropenis and cryptorchidism have been reported in this syndrome, WITKOS has not been formally associated with CHH so far. PATIENTS AND METHODS: A man with KS associated with mild syndromic features (S1) and a boy with global developmental delay, syndromic short stature, micropenis and cryptorchidism (S2), in whom common genetic defects associated with CHH and short stature had been previously excluded, were studied by either chromosomal microarray analysis or whole exome sequencing. RESULTS: Rare SIN3A pathogenic variants were identified in these 2 unrelated patients with CHH phenotypic features. A 550 kb deletion at 15q24.1, including the whole SIN3A gene, was identified in S1, and a SIN3A nonsense rare variant (p.Arg471*) was detected in S2. CONCLUSION: These findings lead us to propose a link between SIN3A defects and CHH, especially in syndromic cases, based on these 2 patients with overlapping phenotypes of WITKOS and CHH.

Evidence for a Founder Effect of SDHB Exon 1 Deletion in Brazilian Patients With Paraganglioma.

CONTEXT: Limited information is available concerning the genetic spectrum of pheochromocytoma and paraganglioma (PPGL) patients in South America. Germline SDHB large deletions are very rare worldwide, but most of the individuals harboring the SDHB exon 1 deletion originated from the Iberian Peninsula. OBJECTIVE: Our aim was to investigate the spectrum of SDHB genetic defects in a large cohort of Brazilian patients with PPGLs. METHODS: Genetic investigation of 155 index PPGL patients was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification, and/or target next-generation sequencing panel. Common ancestrality was investigated by microsatellite genotyping with haplotype reconstruction, and analysis of deletion breakpoint. RESULTS: Among 155 index patients, heterozygous germline SDHB pathogenic or likely pathogenic variants were identified in 22 cases (14.2%). The heterozygous SDHB exon 1 complete deletion was the most frequent genetic defect in SDHB, identified in 8 out of 22 (36%) of patients. Haplotype analysis of 5 SDHB flanking microsatellite markers demonstrated a significant difference in haplotype frequencies in a case-control permutation test (P = 0.03). More precisely, 3 closer/informative microsatellites were shared by 6 out of 8 apparently unrelated cases (75%) (SDHB-GATA29A05-D1S2826-D1S2644 | SDHB-186-130-213), which was observed in only 1 chromosome (1/42) without SDHB exon 1 deletion (X2 = 29.43; P < 0.001). Moreover, all cases with SDHB exon 1 deletion had the same gene breakpoint pattern of a 15 678 bp deletion previously described in the Iberian Peninsula, indicating a common origin. CONCLUSION: The germline heterozygous SDHB exon 1 deletion was the most frequent genetic defect in the Brazilian PPGL cohort. Our findings demonstrated a founder effect for the SDHB exon 1 deletion in Brazilian patients with paragangliomas.

The Congenital and Acquired Mechanisms Implicated in the Etiology of Central Precocious Puberty.

The etiology of central precocious puberty (CPP) is multiple and heterogeneous, including congenital and acquired causes that can be associated with structural or functional brain alterations. All causes of CPP culminate in the premature pulsatile secretion of hypothalamic GnRH and, consequently, in the premature reactivation of hypothalamic-pituitary-gonadal axis. The activation of excitatory factors or suppression of inhibitory factors during childhood represent the 2 major mechanisms of CPP, revealing a delicate balance of these opposing neuronal pathways. Hypothalamic hamartoma (HH) is the most well-known congenital cause of CPP with central nervous system abnormalities. Several mechanisms by which hamartoma causes CPP have been proposed, including an anatomical connection to the anterior hypothalamus, autonomous neuroendocrine activity in GnRH neurons, trophic factors secreted by HH, and mechanical pressure applied to the hypothalamus. The importance of genetic and/or epigenetic factors in the underlying mechanisms of CPP has grown significantly in the last decade, as demonstrated by the evidence of genetic abnormalities in hypothalamic structural lesions (eg, hamartomas, gliomas), syndromic disorders associated with CPP (Temple, Prader-Willi, Silver-Russell, and Rett syndromes), and isolated CPP from monogenic defects (MKRN3 and DLK1 loss-of-function mutations). Genetic and epigenetic discoveries involving the etiology of CPP have had influence on the diagnosis and familial counseling providing bases for potential prevention of premature sexual development and new treatment targets in the future. Global preventive actions inducing healthy lifestyle habits and less exposure to endocrine-disrupting chemicals during the lifespan are desirable because they are potentially associated with CPP.

Retrospective Analysis of Prognostic Factors in Pediatric Patients with Adrenocortical Tumor from Unique Tertiary Center with Long-Term Follow-Up.

Pediatric adrenocortical tumors (PACTs) represent rare causes of malignancies. However, the south/southeast regions of Brazil are known to have a high incidence of PACTs because of the founder effect associated with a germline pathogenic variant of tumor suppressor gene TP53. We aimed to retrospectively analyze the types of variables among hormone production, radiological imaging, tumor staging, histological and genetic features that were associated with the occurrence of malignancy in 95 patients (71% females) with PACTs from a unique center. The worst prognosis was associated with those aged > 3 years (p < 0.05), high serum levels of 11-desoxicortisol (p < 0.001), tumor weight ≥ 200 g (p < 0.001), tumor size ≥ 5 cm (p < 0.05), Weiss score ≥ 5 (p < 0.05), Wieneke index ≥ 3 (p < 0.001) and Ki67 ≥ 15% (p < 0.05). Furthermore, patients with MacFarlane stage IV had an overall survival rate almost two times shorter than patients with other stages (p < 0.001). Additionally, the subtractions of BUB1B-PINK1 (<6.95) expression (p < 0.05) and IGF-IR overexpression (p = 0.0001) were associated with malignant behavior. These results helped identify patients who are likely to have an aggressive course; further multicenter prospective studies are required to confirm our results. In conclusion, PACTs with these patterns of prognostic factors could be treated using an adjuvant approach that may improve the overall survival in such patients.

Applying precision medicine to the diagnosis and management of endocrine disorders.

Precision medicine employs digital tools and knowledge of a patient's genetic makeup, environment and lifestyle to improve diagnostic accuracy and to develop individualised treatment and prevention strategies. Precision medicine has improved management in a number of disease areas, most notably in oncology, and it has the potential to positively impact others, including endocrine disorders. The accuracy of diagnosis in young patients with growth disorders can be improved by using biomarkers. Insulin-like growth factor I (IGF-I) is the most widely accepted biomarker of growth hormone secretion, but its predictive value for recombinant human growth hormone treatment response is modest and various factors can affect the accuracy of IGF-I measurements. These factors need to be taken into account when considering IGF-I as a component of precision medicine in the management of growth hormone deficiency. The use of genetic analyses can assist with diagnosis by confirming the aetiology, facilitate treatment decisions, guide counselling and allow prompt intervention in children with pubertal disorders, such as central precocious puberty and testotoxicosis. Precision medicine has also proven useful during the transition of young people with endocrine disorders from paediatric to adult services when patients are at heightened risk of dropping out from medical care. An understanding of the likelihood of ongoing GH deficiency, using tools such as MRI, detailed patient history and IGF-I levels, can assist in determining the need for continued recombinant human growth hormone treatment during the process of transitional care.

Novel OTX2 loss of function variant associated with congenital hypopituitarism without eye abnormalities.

OBJECTIVES: The normal development of the pituitary gland requires multiple induction signals and transcription factors encoded by more than 30 genes, including OTX2. OTX2 mutations have been described with eye abnormalities and variable congenital hypopituitarism, but rarely with hypopituitarism without ocular manifestations. CASE PRESENTATION: We report a girl with hypopituitarism associated with pituitary hypoplasia and pituitary stalk atrophy, without ocular manifestations. NGS revealed a novel heterozygous mutation in OTX2 c.426dupC:p.(Ser143Leufs*2). CONCLUSIONS: Mutations in the transcription factor OTX2 have been associated with ocular, craniofacial, and pituitary development anomalies. Here we describe a novel mutation in OTX2 associated with hypopituitarism without an ocular phenotype.

Genetic and clinical aspects of paediatric pheochromocytomas and paragangliomas.

OBJECTIVE: Few and conflicting reports have characterized the genetics of paediatric pheochromocytomas and paragangliomas (PPGLs). This study aimed to investigate the clinical and genetic features of Brazilian children with PPGL. PATIENTS AND METHODS: This study included 25 children (52% girls) with PPGL. The median age at diagnosis was 15 years (4-19). The median time of follow-up was 145 months. The genetic investigation was performed by Sanger DNA sequencing, multiplex ligation-dependent probe amplification and/or target next-generation sequencing panel. RESULTS: Of the 25 children with PPGL, 11 (44%), 4 (16%), 2 (8%), 1 (4%) and 7 (28%) had germline VHL pathogenic variants, SDHB, SDHD, RET and negative genetic investigation, respectively. Children with germline VHL missense pathogenic variants were younger than those with SDHB or SDHD genetic defects [median (range), 12 (4-16) vs. 15.5 (14-19) years; P = .027]. Moreover, 10 of 11 cases with VHL pathogenic variants had bilateral pheochromocytoma (six asynchronous and four synchronous). All children with germline SDHB pathogenic variants presented with abdominal paraganglioma (one of them malignant). The two cases with SDHD pathogenic variants presented with head and neck paraganglioma. Among the cases without a genetic diagnosis, 6 and 2 had pheochromocytoma and paraganglioma, respectively. Furthermore, metastatic PPGL was diagnosed in four (16%) of 25 PPGL. CONCLUSIONS: Most of the paediatric PPGL were hereditary and multifocal. The majority of the affected genes belong to pseudohypoxic cluster 1, with VHL being the most frequently mutated. Therefore, our findings impact surgical management and surveillance of children with PPGL.

Phosphodiesterase 2A and 3B variants are associated with primary aldosteronism.

Familial primary aldosteronism (PA) is rare and mostly diagnosed in early-onset hypertension (HT). However, 'sporadic' bilateral adrenal hyperplasia (BAH) is the most frequent cause of PA and remains without genetic etiology in most cases. Our aim was to investigate new genetic defects associated with BAH and PA. We performed whole-exome sequencing (paired blood and adrenal tissue) in six patients with PA caused by BAH that underwent unilateral adrenalectomy. Additionally, we conducted functional studies in adrenal hyperplastic tissue and transfected cells to confirm the pathogenicity of the identified genetic variants. Rare germline variants in phosphodiesterase 2A (PDE2A) and 3B (PDE3B) genes were identified in three patients. The PDE2A heterozygous variant (p.Ile629Val) was identified in a patient with BAH and early-onset HT at 13 years of age. Two PDE3B heterozygous variants (p.Arg217Gln and p.Gly392Val) were identified in patients with BAH and HT diagnosed at 18 and 33 years of age, respectively. A strong PDE2A staining was found in all cases of BAH in zona glomerulosa and/or micronodules (that were also positive for CYP11B2). PKA activity in frozen tissue was significantly higher in BAH from patients harboring PDE2A and PDE3B variants. PDE2A and PDE3B variants significantly reduced protein expression in mutant transfected cells compared to WT. Interestingly, PDE2A and PDE3B variants increased SGK1 and SCNN1G/ENaCg at mRNA or protein levels. In conclusion, PDE2A and PDE3B variants were associated with PA caused by BAH. These novel genetic findings expand the spectrum of genetic etiologies of PA.

Genotype-Phenotype Correlations in Central Precocious Puberty Caused by MKRN3 Mutations.

CONTEXT: Loss-of-function mutations of makorin RING finger protein 3 (MKRN3) are the most common monogenic cause of familial central precocious puberty (CPP). OBJECTIVE: To describe the clinical and hormonal features of a large cohort of patients with CPP due to MKRN3 mutations and compare the characteristics of different types of genetic defects. METHODS: Multiethnic cohort of 716 patients with familial or idiopathic CPP screened for MKRN3 mutations using Sanger sequencing. A group of 156 Brazilian girls with idiopathic CPP (ICPP) was used as control group. RESULTS: Seventy-one patients (45 girls and 26 boys from 36 families) had 18 different loss-of-function MKRN3 mutations. Eight mutations were classified as severe (70% of patients). Among the 71 patients, first pubertal signs occurred at 6.2 ±â€…1.2 years in girls and 7.1 ±â€…1.5 years in boys. Girls with MKRN3 mutations had a shorter delay between puberty onset and first evaluation and higher follicle-stimulating hormone levels than ICPP. Patients with severe MKRN3 mutations had a greater bone age advancement than patients with missense mutations (2.3 ±â€…1.6 vs 1.6 ±â€…1.4 years, P = .048), and had higher basal luteinizing hormone levels (2.2 ±â€…1.8 vs 1.1 ±â€…1.1 UI/L, P = .018) at the time of presentation. Computational protein modeling revealed that 60% of the missense mutations were predicted to cause protein destabilization. CONCLUSION: Inherited premature activation of the reproductive axis caused by loss-of-function mutations of MKRN3 is clinically indistinct from ICPP. However, the type of genetic defect may affect bone age maturation and gonadotropin levels.

XAF1 as a modifier of p53 function and cancer susceptibility.

Cancer risk is highly variable in carriers of the common TP53-R337H founder allele, possibly due to the influence of modifier genes. Whole-genome sequencing identified a variant in the tumor suppressor XAF1 (E134*/Glu134Ter/rs146752602) in a subset of R337H carriers. Haplotype-defining variants were verified in 203 patients with cancer, 582 relatives, and 42,438 newborns. The compound mutant haplotype was enriched in patients with cancer, conferring risk for sarcoma (P = 0.003) and subsequent malignancies (P = 0.006). Functional analyses demonstrated that wild-type XAF1 enhances transactivation of wild-type and hypomorphic TP53 variants, whereas XAF1-E134* is markedly attenuated in this activity. We propose that cosegregation of XAF1-E134* and TP53-R337H mutations leads to a more aggressive cancer phenotype than TP53-R337H alone, with implications for genetic counseling and clinical management of hypomorphic TP53 mutant carriers.

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

The identification of loss-of-function mutations in MKRN3 in patients with central precocious puberty in association with the decrease in MKRN3 expression in the medial basal hypothalamus of mice before the initiation of reproductive maturation suggests that MKRN3 is acting as a brake on gonadotropin-releasing hormone (GnRH) secretion during childhood. In the current study, we investigated the mechanism by which MKRN3 prevents premature manifestation of the pubertal process. We showed that, as in mice, MKRN3 expression is high in the hypothalamus of rats and nonhuman primates early in life, decreases as puberty approaches, and is independent of sex steroid hormones. We demonstrated that Mkrn3 is expressed in Kiss1 neurons of the mouse hypothalamic arcuate nucleus and that MKRN3 repressed promoter activity of human KISS1 and TAC3, 2 key stimulators of GnRH secretion. We further showed that MKRN3 has ubiquitinase activity, that this activity is reduced by MKRN3 mutations affecting the RING finger domain, and that these mutations compromised the ability of MKRN3 to repress KISS1 and TAC3 promoter activity. These results indicate that MKRN3 acts to prevent puberty initiation, at least in part, by repressing KISS1 and TAC3 transcription and that this action may involve an MKRN3-directed ubiquitination-mediated mechanism.

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.