Mutations in MAP3K1 that cause 46,XY disorders of sex development disrupt distinct structural domains in the protein.

Missense mutations in the gene, MAP3K1, are a common cause of 46,XY gonadal dysgenesis, accounting for 15-20% of cases [Ostrer, 2014, Disorders of sex development (DSDs): an update. J. Clin. Endocrinol. Metab., 99, 1503-1509]. Functional studies demonstrated that all of these mutations cause a protein gain-of-function that alters co-factor binding and increases phosphorylation of the downstream MAP kinase pathway targets, MAPK11, MAP3K and MAPK1. This dysregulation of the MAP kinase pathway results in increased CTNNB1, increased expression of WNT4 and FOXL2 and decreased expression of SRY and SOX9. Unique and recurrent pathogenic mutations cluster in three semi-contiguous domains outside the kinase region of the protein, a newly identified N-terminal domain that shares homology with the Guanine Exchange Factor (residues Met164 to Glu231), a Plant HomeoDomain (residues Met442 to Trp495) and an ARMadillo repeat domain (residues Met566 to Glu862). Despite the presence of the mutation clusters and clinical data, there exists a dearth of mechanistic insights behind the development imbalance. In this paper, we use structural modeling and functional data of these mutations to understand alterations of the MAP3K1 protein and the effects on protein folding, binding and downstream target phosphorylation. We show that these mutations have differential effects on protein binding depending on the domains in which they occur. These mutations increase the binding of the RHOA, MAP3K4 and FRAT1 proteins and generally decrease the binding of RAC1. Thus, pathologies in MAP3K1 disrupt the balance between the pro-kinase activities of the RHOA and MAP3K4 binding partners and the inhibitory activity of RAC1.

A 46,XX testicular disorder of sex development caused by a Wilms' tumour Factor-1 (WT1) pathogenic variant.

Molecular diagnosis is rarely established in 46,XX testicular (T) disorder of sex development (DSD) individuals with atypical genitalia. The Wilms' tumour factor-1 (WT1) gene is involved in early gonadal development in both sexes. Classically, WT1 deleterious variants are associated with 46,XY disorders of sex development (DSD) because of gonadal dysgenesis. We report a novel frameshift WT1 variant identified in an SRY-negative 46,XX testicular DSD girl born with atypical genitalia. Target massively parallel sequencing involving DSD-related genes identified a novel heterozygous WT1 c.1453_1456del; p.Arg485Glyfs*14 variant located in the fourth zinc finger of the protein which is absent in the population databases. Segregation analysis and microsatellite analysis confirmed the de novo status of the variant that is predicted to be deleterious by in silico tools and to increase WT1 target activation in crystallographic model. This novel and predicted activating frameshift WT1 variant leading to the 46,XX testicular DSD phenotype includes the fourth zinc-finger DNA-binding domain defects in the genetic aetiology of 46,XX DSD.

Biallelic and monoallelic ESR2 variants associated with 46,XY disorders of sex development.

PURPOSE: Disorders or differences of sex development (DSDs) are rare congenital conditions characterized by atypical sex development. Despite advances in genomic technologies, the molecular cause remains unknown in 50% of cases. METHODS: Homozygosity mapping and whole-exome sequencing revealed an ESR2 variant in an individual with syndromic 46,XY DSD. Additional cases with 46,XY DSD underwent whole-exome sequencing and targeted next-generation sequencing of ESR2. Functional characterization of the identified variants included luciferase assays and protein structure analysis. Gonadal ESR2 expression was assessed in human embryonic data sets and immunostaining of estrogen receptor-ß (ER-ß) was performed in an 8-week-old human male embryo. RESULTS: We identified a homozygous ESR2 variant, c.541_543del p.(Asn181del), located in the highly conserved DNA-binding domain of ER-ß, in an individual with syndromic 46,XY DSD. Two additional heterozygous missense variants, c.251G>T p.(Gly84Val) and c.1277T>G p.(Leu426Arg), located in the N-terminus and the ligand-binding domain of ER-ß, were found in unrelated, nonsyndromic 46,XY DSD cases. Significantly increased transcriptional activation and an impact on protein conformation were shown for the p.(Asn181del) and p.(Leu426Arg) variants. Testicular ESR2 expression was previously documented and ER-ß immunostaining was positive in the developing intestine and eyes. CONCLUSION: Our study supports a role for ESR2 as a novel candidate gene for 46,XY DSD.

Long-term outcomes and molecular analysis of a large cohort of patients with 46,XY disorder of sex development due to partial gonadal dysgenesis.

BACKGROUND: Follow-up data on patients with 46,XY partial gonadal dysgenesis (PGD) until adulthood are scarce, making information on prognosis difficult. OBJECTIVE: To analyse the long-term outcomes of patients with 46,XY PGD regarding testosterone production, germ cell tumour risk, genotype and psychosexual adaptation. METHODS: A retrospective longitudinal study of 33 patients (20 assigned male and 13 patients assigned female at birth). Molecular diagnosis was performed by Sanger sequencing or by targeted massively parallel sequencing of 63 genes related to disorders of sex development (DSDs). RESULTS: Age at first and last visit ranged from 0.1 to 43 and from 17 to 53 years, respectively. Spontaneous puberty was observed in 57% of the patients. During follow-up, six of them had a gonadectomy (four due to female gender, and two because of a gonadal tumour). At last evaluation, five of six patients had adult male testosterone levels (median 16.7 nmol/L, range 15.3-21.7 nmol/L) and elevated LH and FSH levels. Germ cell tumours were found in two postpubertal patients (one with an abdominal gonad and one patient with Frasier syndrome). Molecular diagnosis was possible in 11 patients (33%). NR5A1 variants were the most prevalent molecular defects (n = 6), and four of five patients harbouring them developed spontaneous puberty. Gender change was observed in four patients, two from each sex assignment group; all patients reported satisfaction with their gender at final evaluation. Sexual intercourse was reported by 81% of both gender and 82% of them reported satisfaction with their sexual lives. CONCLUSION: Spontaneous puberty was observed in 57% of the patients with 46,XY PGD, being NR5A1 defects the most prevalent ones among all the patients and in those with spontaneous puberty. Gender change due to gender dysphoria was reported by 12% of the patients. All the patients reported satisfaction with their final gender, and most of them with their sexual life.

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.

WT1 Pathogenic Variants are Associated with a Broad Spectrum of Differences in Sex Development Phenotypes and Heterogeneous Progression of Renal Disease.

Wilms' tumor suppressor gene 1 (WT1) plays an essential role in urogenital and kidney development. Heterozygous germline pathogenic allelic variants of WT1 have been classically associated with Denys-Drash syndrome (DDS) and Frasier syndrome (FS). Usually, exonic pathogenic missense variants in the zinc finger region are the cause of DDS, whereas pathogenic variants affecting the canonic donor lysine-threonine-serine splice site in intron 9 cause FS. Phenotypic overlap between WT1 disorders has been frequently observed. New WT1 variant-associated phenotypes, such as 46,XX testicular/ovarian-testicular disorders of sex development (DSD) and primary ovarian insufficiency, have been reported. In this report, we describe the phenotypes and genotypes of 7 Brazilian patients with pathogenic WT1 variants. The molecular study involved Sanger sequencing and massively parallel targeted sequencing using a DSD-associated gene panel. Six patients (5 with a 46,XY karyotype and 1 with a 46,XX karyotype) were initially evaluated for atypical genitalia, and a 46,XY patient with normal female genitalia sought medical attention for primary amenorrhea. Germ cell tumors were identified in 2 patients, both with variants affecting alternative splicing of WT1 between exons 9 and 10. Two pathogenic missense WT1 variants were identified in two 46,XY individuals with Wilms' tumors; both patients were <1 year of age at the time of diagnosis. A novel WT1 variant, c.1453_1456 (p.Arg485Glyfs*14), was identified in a 46,XX patient with testicular DSD. Nephrotic proteinuria was diagnosed in all patients, including 3 who underwent renal transplantation after progressing to end-stage kidney disease. The expanding phenotypic spectrum associated with WT1 variants in XY and XX individuals confirms their pivotal role in gonadal and renal development as well as in tumorigenesis, emphasizing the clinical implications of these variants in genetic diagnosis.

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.

Assembling the jigsaw puzzle: CBX2 isoform 2 and its targets in disorders/differences of sex development.

BACKGROUND: One of the defining moments of human life occurs early during embryonic development, when individuals sexually differentiate into either male or female. Perturbation of this process can lead to disorders/differences of sex development (DSD). Chromobox protein homolog 2 (CBX2) has two distinct isoforms, CBX2.1 and CBX2.2: the role of CBX2.1 in DSD has been previously established, yet to date the function of the smaller isoform CBX2.2 remains unknown. METHODS: The genomic DNA of two 46,XY DSD patients was analysed using whole exome sequencing. Furthermore, protein/DNA interaction studies were performed using DNA adenine methyltransferase identification (DamID) to identify putative binding partners of CBX2. Finally, in vitro functional studies were used to elucidate the effect of wild-type and variant CBX2.2 on selected downstream targets. RESULTS: Here, we describe two patients with features of DSD i.e. atypical external genitalia, perineal hypospadias and no palpable gonads, each patient carrying a distinct CBX2.2 variant, p.Cys132Arg (c.394T>C) and p.Cys154fs (c.460delT). We show that both CBX2.2 variants fail to regulate the expression of genes essential for sexual development, leading to a severe 46,XY DSD defect, likely because of a defective expression of EMX2 in the developing gonad. CONCLUSION: Our study indicates a distinct function of the shorter form of CBX2 and by identifying several of its unique targets, can advance our understanding of DSD pathogenesis and ultimately DSD diagnosis and management.

Heterozygous Nonsense Mutation in the Androgen Receptor Gene Associated with Partial Androgen Insensitivity Syndrome in an Individual with 47,XXY Karyotype.

There are only 2 patients with 47,XXY karyotype and androgen receptor (AR) gene mutation reported in the literature, and both are diagnosed as complete androgen insensitivity syndrome (CAIS). We report a 22-year-old female with 47,XXY karyotype and atypical external genitalia. Sequencing of AR revealed the heterozygous p.Asn849Lys*32 mutation, and extensive X chromosome microsatellite analysis showed homozygosity for Xp and heterozygosity for Xq, suggesting partial X maternal isodisomy. Partial androgen insensitivity syndrome (PAIS) developed in this case, probably because of the presence of the heterozygous AR mutation and random X- inactivation of the healthy allele. This is the first report of a female patient with 47,XXY karyotype and PAIS phenotype.