The genetic spectrum of a Chinese series of patients with 46, XY disorders of the sex development.

PURPOSE: The etiology of 46, XY disorders of sex development (46, XY DSD) is complex, and studies have shown that different series of patients with 46, XY DSD has different genetic spectrum. In this study, we aimed to investigate the underlying genetic etiology in a Chinese series of patients with 46, XY DSD by whole exome sequencing (WES). METHODS: Seventy patients with 46, XY DSD were enrolled from the Peking Union Medical College Hospital (Beijing, China). The detailed clinical characteristics were evaluated, and peripheral blood was collected for WES to find the patients' rare variants (RVs) of genes related to 46, XY DSD. The clinical significance of the RVs was annotated according to American College of Medical Genetics and Genomics (ACMG) guidelines. RESULTS: A total of 57 RVs from nine genes were identified in 56 patients with 46, XY DSD, which include 21 novel RVs and 36 recurrent RVs. Based on the American ACMG guidelines, 43 variants were classified as pathogenic(P) or likely pathogenic (LP) variants and 14 variants were defined as variants of uncertain significance (VUS). P or LP variants were identified in 64.3% (45/70) patients of the series. Thirty-nine, 14, and 4 RVs were involved in the process of androgen synthesis and action, testicular determination and developmental process, and syndromic 46, XY DSD, respectively. The top three genes most frequently affected to cause 46, XY DSD were AR, SRD5A2, and NR5A1. Seven patients were found harboring RVs of the 46, XY DSD pathogenic genes identified in recent years, namely DHX37 in four patients, MYRF in two patients, and PPP2R3C in one patient. CONCLUSION: We identified 21 novel RVs of nine genes, which extended the genetic spectrum of 46, XY DSD pathogenic variants. Our study showed that 60% of the patients were caused by AR, SRD5A2 or NR5A1 P/LP variants. Therefore, polymerase chain reaction (PCR) amplification and Sanger sequencing of these three genes could be performed first to identify the pathogeny of the patients. For those patients whose pathogenic variants had not been found, whole-exome sequencing could be helpful in determining the etiology.

A novel c.64G > T (p.G22C) NR5A1 variant in a Chinese adolescent with 46,XY disorders of sex development: a case report.

BACKGROUND: Adolescents with 46,XY disorders of sex development (DSD) face additional medical and psychological challenges. To optimize management and minimize hazards, correct and early clinical and molecular diagnosis is necessary. CASE PRESENTATION: We report a 13-year-old Chinese adolescent with absent Müllerian derivatives and suspected testis in the inguinal area. History, examinations, and assistant examinations were available for clinical diagnosis of 46,XY DSD. The subsequent targeting specific disease-causing genes, comprising 360 endocrine disease-causing genes, was employed for molecular diagnosis. A novel variation in nuclear receptor subfamily 5 group A member 1 (NR5A1) [c.64G > T (p.G22C)] was identified in the patient. In vitro functional analyses of the novel variant suggested no impairment to NR5A1 mRNA or protein expression relative to wild-type, and immunofluorescence confirmed similar localization of NR5A1 mutant to the cell nucleus. However, we observed decreased DNA-binding affinity by the NR5A1 variant, while dual-luciferase reporter assays showed that the mutant effectively downregulated the transactivation capacity of anti-Müllerian hormone. We described a novel NR5A1 variant and demonstrated its adverse effects on the functional integrity of the NR5A1 protein resulting in serious impairment of its modulation of gonadal development. CONCLUSIONS: This study adds one novel NR5A1 variant to the pool of pathogenic variants and enriches the adolescents of information available about the mutation spectrum of this gene in Chinese population.

Genetic Variants in SRD5A2 in a Spectrum of DSD Patients from Australian Clinics Highlight Importance of Genetic Testing alongside Typical First-Line Investigations.

INTRODUCTION: Steroid 5-alpha reductase deficiency (5α-R2D) is a rare condition caused by genetic variants that reduce the activity of the enzyme that converts testosterone into dihydrotestosterone. The clinical spectrum of 5α-R2D is known to overlap with other 46,XY differences of sex development (DSD) such as androgen insensitivity or gonadal dysgenesis. However, the clinical trajectories of the aetiologies can differ, with 5α-R2D presenting its own challenges. METHODS: In this study, we have collated clinical information for five individuals with variants in SRD5A2 identified using research genetic testing in an Australian paediatric setting. RESULTS: We describe how a genetic finding resolved or confirmed a diagnosis for these individuals and how it guided clinical management and family counselling. CONCLUSION: This work highlights the importance of early genetic testing in children born with 46,XY DSD where it complements traditional first-line testing.

The Molecular Basis of 5α-Reductase Type 2 Deficiency.

The 5α-reductase type 2 enzyme catalyzes the conversion of testosterone into dihydrotestosterone, playing a crucial role in male development. This enzyme is encoded by the SRD5A2 gene, which maps to chromosome 2 (2p23), consists of 5 exons and 4 introns, and encodes a 254 amino acid protein. Disruptions in this gene are the molecular etiology of a subgroup of differences of sex development (DSD) in 46,XY patients. Affected individuals present a large range of external genitalia undervirilization, ranging from almost typically female external genitalia to predominantly typically male external genitalia with minimal undervirilization, including isolated micropenis. This is an updated review of the implication of the SRD5A2 gene in 5α-reductase type 2 enzyme deficiency. For that, we identified 451 cases from 48 countries of this particular 46,XY DSD from the literature with reported variants in the SRD5A2 gene. Herein, we present the SRD5A2 mutational profile, the SRD5A2 polymorphisms, and the functional studies related to SRD5A2 variants to detail the molecular etiology of this condition.

Primary Amenorrhea Due to Anatomical Abnormalities of the Reproductive Tract: Molecular Insight.

Congenital anomalies of the female reproductive tract that present with primary amenorrhea involve Müllerian aplasia, also known as Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS), and cervical and vaginal anomalies that completely obstruct the reproductive tract. Karyotype abnormalities do not exclude the diagnosis of MRKHS. Familial cases of Müllerian anomalies and associated malformations of the urinary and skeletal systems strongly suggest a complex genetic etiology, but so far, the molecular mechanism in the vast majority of cases remains unknown. Primary amenorrhea may also be the first presentation of complete androgen insensitivity syndrome, steroid 5α-reductase type 2 deficiency, 17ß-hydroxysteroid dehydrogenase type 3 deficiency, and Leydig cells hypoplasia type 1; therefore, these disorders should be considered in the differential diagnosis of the congenital absence of the uterus and vagina. The molecular diagnosis in the majority of these cases can be established.

Genome analyses and androgen quantification for an infant with 5α-reductase type 2 deficiency.

OBJECTIVES: 5α-reductase type 2 deficiency due to biallelic SRD5A2 variants is a common form of 46,XY disorders of sex development. CASE PRESENTATION: A Chinese neonate presented with ambiguous genitalia. He carried a homozygous likely_pathogenic SRD5A2 variant (c.650C>A, p.A217E). His apparently nonconsanguineous parents were heterozygotes for the variant. The variant has previously been identified in two Chinese patients. Our patient carried 14.2 Mb loss-of-heterogeneity regions distributed in the genome. The SRD5A2 variant in this family was invariably coupled with two polymorphisms in exon 1 and intron 1. In the patient, blood testosterone (T)/5α-dihydrotestosterone (5αDHT) ratios were elevated before and during mini puberty, and were higher when measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) than measured by conventional immune assays. CONCLUSIONS: This study provides evidence for the founder effect of an SRD5A2 variant. Furthermore, our data indicate that there is a need to establish a new reference value for T/5αDHT ratios using LC-MS/MS.

Clinical and molecular characterization of thirty Chinese patients with congenital lipoid adrenal hyperplasia.

Congenital lipoid adrenal hyperplasia (LCAH), as the most severe form of congenital adrenal hyperplasia (CAH), is caused by mutations in the steroidogenic acute regulatory protein (STAR). Affected patients were typically characterized by adrenal insufficiency in the first year of life and present with female external genitalia regardless of karyotype. Non-classic LCAH patients usually present from 2 to 4 years old with glucocorticoid deficiency and mild mineralocorticoid deficiency, even develop naturally masculinized external genitalia at birth when they have 46,XY karyotype. We described thirty patients from unrelated Chinese families, including three non-classic LCAH ones. Four novel mutations were reported, including c.556A > G, c.179-15G > T, c.695delG and c.306 + 3_c.306 + 6delAAGT. The c.772C > T is the most common STAR mutation in Chinese population, suggesting a possibility of founder effect. Enzymatic activity assay combined with clinical characteristics showed a good genotype-phenotype correlation in this study. Residual STAR activity more than 20 % may be correlated with non-classic LCAH phenotype. We support the perspective that onset age may be affected by multiple factors and masculinization should be the main weighting factor for diagnosis of non-classic LCAH. Compared with 46,XX LCAH patients, less 46,XY ones were found in our report. A less comprehensive inspection and an easy diagnosis due to classical phenotype both would reduce the possibility of 46,XY LCAH patients to be referred to specialists or geneticists.

Variants of STAR, AMH and ZFPM2/FOG2 May Contribute towards the Broad Phenotype Observed in 46,XY DSD Patients with Heterozygous Variants of NR5A1.

Variants of NR5A1 are often found in individuals with 46,XY disorders of sex development (DSD) and manifest with a very broad spectrum of clinical characteristics and variable sex hormone levels. Such complex phenotypic expression can be due to the inheritance of additional genetic hits in DSD-associated genes that modify sex determination, differentiation and organ function in patients with heterozygous NR5A1 variants. Here we describe the clinical, biochemical and genetic features of a series of seven patients harboring monoallelic variants in the NR5A1 gene. We tested the transactivation activity of novel NR5A1 variants. We additionally included six of these patients in a targeted diagnostic gene panel for DSD and identified a second genetic hit in known DSD-causing genes STAR, AMH and ZFPM2/FOG2 in three individuals. Our study increases the number of NR5A1 variants related to 46,XY DSD and supports the hypothesis that a digenic mode of inheritance may contribute towards the broad spectrum of phenotypes observed in individuals with a heterozygous NR5A1 variation.

46,XY DSD and limb abnormalities in a female with a de novo LHX9 missense mutation.

Differences in sex development (DSD) are a group of rare conditions involving genes, hormones and reproductive organs, including genitals. Although these disorders are common, information about the molecular causes remain limited. Many genes have been identified in association with DSD but in many cases the causative gene could not be identified. The Lhx9 gene has been studied in mice and birds, and biallelic mutations in this gene have been found to cause 46,XY DSD and limb abnormalities. So far two variants of LHX9 have been identified in 46,XY individuals with testicular regression, micropenis and hypospadias. We report a de novo heterozygous missense variant in LHX9 in a girl with 46,XY DSD and finger and toe abnormalities. It was previously predicted that a mutation in LHX9 would not cause extragenital anomalies in light of prior animal studies, but our report adds to the limited knowledge of the phenotype observed in humans with a variant in LHX9. To the best of our knowledge this is the first reported case with this combination of abnormalities.

Persistent Mullerian duct syndrome: rare presentation in an elderly man.

Persistent Mullerian duct syndrome has been described as a disease of internal male pseudohermaphroditism, a rare autosomal recessive disease, characterised by persistent Mullerian derivatives in patients with male pattern 46, XY karyotype and normal pattern virilisation. We present a case of an elderly man, who on evaluation for bilateral undescended testes was found to have a pelvic mass suggestive of malignant transformation of an undescended testis on imaging. On surgical exploration, uterus with multiple fibroids, bilateral fallopian tubes, cervix and bilateral atrophic testes were identified. Interestingly, in this case, imaging (contrastCT and MRI) had missed Mullerian structures due to varied presentation, but exploration and excision of the structures followed by their histopathology revealed uterine leiomyomas and confirmed other Mullerian structures (bilateral fallopian tubes, cervix) with bilateral testes.

Clinical characteristics and genotype-phenotype correlations of 130 Chinese children in a high-homogeneity single-center cohort with 5α-reductase 2 deficiency.

BACKGROUND: Patients with steroid 5α-reductase 2 deficiency (5α-RD) caused by SRD5A2 (OMIM #607306) variants present variable genotypes and phenotypes. The genotype-phenotype correlations remain unclear. METHODS: We investigated genotype-phenotype correlations of SRD5A2 variants in a large Chinese single-center cohort. Phenotypes were categorized using the external masculinization score (EMS), urethral meatus and gonad position, and penile length-standard deviation score. RESULTS: Of the 130 included patients, 113 had hypospadias, and 17 had a normal urethral meatus position. Testosterone/dihydrotestosterone (T/DHT) values were not significantly associated with phenotypic severity (p = 0.539-0.989). Of the 31 SRD5A2 variants, including 10 novel variants, p.R227Q was the most prevalent (39.62%), followed by p.Q6* (16.92%), p.R246Q (13.46%), and p.G203S (10.38%). Compared to biallelic missense mutations, biallelic nonsense mutations were associated with a lower EMS and urethral meatus score (p = 0.009 and p = 0.024, respectively). Patients homozygous for p.R227Q exhibited mild and variable phenotypes, while those homozygous for p.Q6*, p.R246Q, or p.G203S showed consistently severe phenotypes. The phenotypes were variable and milder in patients with compound heterozygosity for p.R227Q and these mutations. CONCLUSION: T/DHT does not predict phenotype severity. The most prevalent SRD5A2 variant in Han Chinese is p.R227Q, which is associated with milder phenotypes and greater phenotypic variability. SRD5A2 variants may significantly influence phenotypic variation.

Analysis of variants in GATA4 and FOG2/ZFPM2 demonstrates benign contribution to 46,XY disorders of sex development.

BACKGROUND: GATA-binding protein 4 (GATA4) and Friend of GATA 2 protein (FOG2, also known as ZFPM2) form a heterodimer complex that has been shown to influence transcription of genes in a number of developmental systems. Recent evidence has also shown these genes play a role in gonadal sexual differentiation in humans. Previously we identified four variants in GATA4 and an unexpectedly large number of variants in ZFPM2 in a cohort of individuals with 46,XY Differences/Disorders of Sex Development (DSD) (Eggers et al, Genome Biology, 2016; 17: 243). METHOD: Here, we review variant curation and test the functional activity of GATA4 and ZFPM2 variants. We assess variant transcriptional activity on gonadal specific promoters (Sox9 and AMH) and variant protein-protein interactions. RESULTS: Our findings support that the majority of GATA4 and ZFPM2 variants we identified are benign in their contribution to 46,XY DSD. Indeed, only one variant, in the conserved N-terminal zinc finger of GATA4, was considered pathogenic, with functional analysis confirming differences in its ability to regulate Sox9 and AMH and in protein interaction with ZFPM2. CONCLUSIONS: Our study helps define the genetic factors contributing to 46,XY DSD and suggests that the majority of variants we identified in GATA4 and ZFPM2/FOG2 are not causative.

Functional study of a novel c.630delG (p.Y211Tfs*85) mutation in NR5A1 gene in a Chinese boy with 46,XY disorders of sex development.

PURPOSE: This study aimed to present the clinical features and gene mutation characteristics of a child with 46,XY disorders of sex development (DSD) caused by a novel heterozygous mutation in the NR5A1 gene to determine the potential association between this heterozygous mutation and the pathogenesis of 46,XY DSD. METHODS: We present the case of a Chinese child with ambiguous genitalia at birth but a normal adrenal gland. Targeted next-generation sequencing, comprising 163 candidate genes involved in sexual differentiation and development, was performed, followed by the functional evaluation of the novel NR5A1 mutation. RESULT: The patient had a novel heterozygous mutation in the NR5A1 gene, c.630delG (p.Y211Tfs*85). Results revealed that overexpression of p.Y211Tfs*85 impaired steroidogenic factor-1 (SF-1) protein synthesis. Immunofluorescence analysis revealed that both SF-1 wild-type and p.Y211Tfs*85 mutation proteins were localized in the cell nucleus. Furthermore, dual-luciferase reporter assay results revealed that the p.Y211Tfs*85 mutation could effectively downregulate the transcriptional activation of anti-Müllerian hormone and steroidogenic acute regulatory protein genes (P < 0.01). Additionally, the p.Y211Tfs*85 mutation changed three-dimensional conformation of SF-1, and three conformations could be constructed with the mutated amino acid sequences. Therefore, the novel frameshift mutation could result in decreased protein expression of SF-1. CONCLUSION: We described a novel mutation in NR5A1 and showed that it might affect protein structure, thereby seriously compromising the role of SF-1 in regulating gonadal development. The novel p.Y211Tfs*85 mutation in the NR5A1 gene enriches the boy of information available regarding the mutation spectrum of this gene in the Chinese population.

5α-Reductase type 2 deficiency in families from an isolated Andean population in Venezuela.

5α-Reductase type 2 deficiency causes a 46,XY disorder of sex development (DSD) characterized by ambiguous external genitalia, rudimentary prostate, and normal internal genitalia. The disease prevalence worldwide is low, but in a small and isolated village of the Venezuelan Andes, a higher incidence has been found. DNA analysis of the SRD5A2 gene was performed in three inbred affected individuals clinically diagnosed with DSD. The entire coding regions, the p.L89V polymorphism (rs523349) and five intragenic SNPs (rs2300702, rs2268797, rs2268796, rs4952220, rs12470196) used to construct haplotypes were analyzed by Sanger sequencing. To assess the probable ethnic origin of the mutation in this geographic isolate, a population structure analysis was performed. Homozygosis for the p.N193S mutation was found in all patients, with a mutation carrier frequency of 1:80 chromosomes (0.0125) in the geographic focus, suggesting a founder phenomenon. The results of the population structure analysis suggested a mutation origin closer to the Spanish populations, according to the clusters grouping. The genotype-phenotype correlation in the patients was not absolute, being hypospadias and cryptorchidism the main traits that differentiate affected individuals.

Male pseudohermaphroditism with os clitoris in three dogs.

Two American Cocker Spaniels and one Bichon Frise were presented to our veterinary teaching hospital with an enlarged clitoris. Diagnostic imaging showed that the structure was composed of bony material. Exploratory laparotomy revealed uterine-like structures and testes which had an epididymis unilaterally. Surgical removal of internal genitalia, gonads and protruded clitoris were performed well. Histological evaluation revealed; inactive testes, female internal genital tracts with ambisexual ductal remnants, and prominent ossification in the clitoris. All 3 cases were diagnosed with male pseudohermaphroditism. In author's knowledge, this is the first report in Bichon Frise dog with os clitoris and also, it describes not common cases in small dog breeds with os clitoris.

[Preliminary investigation of gender assignment in 46,XY disorders of sex development with severe male undermasculinisation].

Objective: To explore the feasibility of gender assignment in 46,XY disorders of sex development (DSD) with severe undermasculinisation mainly based on molecular diagnosis. Methods: A retrospective study of 45 patients of 46, XY DSD with severe undermasculinisation were admitted between November 2015 and October 2018 at Children's Hospital, Zhejiang University School of Medicine. The initial social gender were all female, of whom the external genital manifestations were Prader 0 to 2; the degree of masculinity was scored using external masculinisation score (EMS); the position and development of the gonads were examined by ultrasound, cystoscopy and laparoscopy, also including assessing the development of the Wolffian tube and the Müllerian tube. The level and ratio of testosterone to dihydrotestosterone before and after hCG stimulation were evaluated for the function of Leydig cell and 5α-reductase-2. Gender role scales and sandbox games were used to assess gender role behavior. Genital sensitivity to androgen stimulation was assessed; A panel including 163 genes related to gender development were determined by second-generation sequencing in all 45 patients. Finally, a multidisciplinary team (MDT) makes a gender assignment after a comprehensive analysis mainly based on the molecular etiological diagnosis. Results: Thirty-nine out of 45 patients (87%) had an identifiable genetic etiology, and the remaining 6 (13%) were negative for genetic testing. Forty-five patients had EMS less than or equal to 3 points. Sexual psychological assessment was performed in 39 patients, with male dominance in 24 (62%) and female dominance in 15 (38%). The gender assignment was 23 cases (51%) for male and 19 cases (42%) for female, and 3 cases (7%) were not completely determined. Conclusions: Molecular diagnosis provides a strong basis for appropriate gender assignment of 46, XY DSD children with severe undermasculinisation. Based on molecular diagnosis, each DSD should be analyzed by professional MDT to analyze the clinical symptoms/signs, gonadal development, gonad tumor risk, external genital morphology, sexual psychological assessment, potential fertility opportunities, parental views, Social and cultural factors, etc. make appropriate gender assignment.

Effects of pre- and post-pubertal dihydrotestosterone treatment on penile length in 5α-reductase type 2 deficiency.

Steroid 5α-reductase type 2 deficiency (5αRD2) is a congenital disorder of sex development caused by impairment of conversion from testosterone (T) to 5α-dihydrotestosterone (DHT). DHT deficiency leads to various degrees of undervirilized external genitalia including micropenis, primarily correlated with mutations of the SRD5A2 gene that encodes 5α-reductase type 2. Four Japanese boys with isolated micropenis were diagnosed as 5αRD2 by elevated ratios of serum T/DHT, and decreased ratios of urinary 5α/5ß-reduced steroid metabolites. Genetic analyses for SRD5A2 identified that the four patients shared a hypomorphic mutation R227Q that has a residual activity related to the mild-form of 5αRD2. For prepubertal micropenis, DHT was transdermally applied to the four patients at the ages of 4-11 year, increasing a median of stretched penile lengths (SPLs) from 2.6 cm (-2.5 SD) to 4.4 cm (-0.2 SD). Nevertheless, the post-pubertal penile growth was apparently retarded, despite normal levels of T secreted from well-developed testes. The second course of DHT treatment underwent at ages of 12-18 year, but unable to normalize SPLs at a range of 6.0 to 7.0 cm (-3.4 to -2.4 SD). The prostate volumes of two patients were variable at 8.1 and 21 cm3, and a sperm cell count of one patient was normal as young adult. DHT treatment contributes to development of the penis and prostate, which are favorable for the potential fertility of 5αRD2 adults. Meanwhile, the retarded penile growth and a risk of prostate overgrowth may complicate the post-pubertal management with DHT for 5αRD2 males.

MYRF haploinsufficiency causes 46,XY and 46,XX disorders of sex development: bioinformatics consideration.

Disorders of sex development (DSDs) are defined as congenital conditions in which chromosomal, gonadal or anatomical sex is atypical. In many DSD cases, genetic causes remain to be elucidated. Here, we performed a case-control exome sequencing study comparing gene-based burdens of rare damaging variants between 26 DSD cases and 2625 controls. We found exome-wide significant enrichment of rare heterozygous truncating variants in the MYRF gene encoding myelin regulatory factor, a transcription factor essential for oligodendrocyte development. All three variants occurred de novo. We identified an additional 46,XY DSD case of a de novo damaging missense variant in an independent cohort. The clinical symptoms included hypoplasia of Müllerian derivatives and ovaries in 46,XX DSD patients, defective development of Sertoli and Leydig cells in 46,XY DSD patients and congenital diaphragmatic hernia in one 46,XY DSD patient. As all of these cells and tissues are or partly consist of coelomic epithelium (CE)-derived cells (CEDC) and CEDC developed from CE via proliferaiton and migration, MYRF might be related to these processes. Consistent with this hypothesis, single-cell RNA sequencing of foetal gonads revealed high expression of MYRF in CE and CEDC. Reanalysis of public chromatin immunoprecipitation sequencing data for rat Myrf showed that genes regulating proliferation and migration were enriched among putative target genes of Myrf. These results suggested that MYRF is a novel causative gene of 46,XY and 46,XX DSD and MYRF is a transcription factor regulating CD and/or CEDC proliferation and migration, which is essential for development of multiple organs.

PTH Modulation by Aldosterone and Angiotensin II is Blunted in Hyperaldosteronism and Rescued by Adrenalectomy.

CONTEXT: Accumulating evidence suggests a link between adrenocortical zona glomerulosa and parathyroid gland through mechanisms that remain unexplored. OBJECTIVES: To test the hypothesis that in vivo angiotensin II blockade affects PTH secretion in patients with hypertension and that aldosterone and angiotensim II directly stimulate PTH secretion ex vivo. DESIGN AND SETTING: We investigated the changes of serum PTH levels induced by oral captopril (50 mg) administration in patients with primary essential hypertension (EH) and with primary aldosteronism (PA) caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenoma (APA), the latter before and after adrenalectomy. We also exposed primary cultures of human parathyroid cells from patients with primary hyperparathyroidism to angiotensin II (10-7 M) and/or aldosterone (10-7 M). RESULTS: Captopril lowered PTH levels (in nanograms per liter) both in patients with EH (n = 63; 25.9 ± 8.3 baseline vs 24.4 ± 8.0 postcaptopril, P < 0.0001) and in patients with APA after adrenalectomy (n = 27; 26.3 ± 11.6 vs 24.0 ± 9.7 P = 0.021). However, it was ineffective in patients with full-blown PA caused by APA and BAH. In primary culture of human parathyroid cells, both aldosterone (P < 0.001) and angiotensin II (P = 0.002) markedly increased PTH secretion from baseline, by acting through mineralocorticoid receptor and angiotensin type 1 receptor, as these effects were abolished by canrenone and irbesartan, respectively. CONCLUSION: These results collectively suggest an implication of the renin-angiotensin-aldosterone system in PTH regulation in humans, at least in PTH-secreting cells obtained from parathyroid tumors. Moreover, they further support the concept that mild hyperparathyroidism is a feature of human PA that is correctable with adrenalectomy.