Formin-mediated nuclear actin at androgen receptors promotes transcription.

Steroid hormone receptors are ligand-binding transcription factors essential for mammalian physiology. The androgen receptor (AR) binds androgens mediating gene expression for sexual, somatic and behavioural functions, and is involved in various conditions including androgen insensitivity syndrome and prostate cancer1. Here we identified functional mutations in the formin and actin nucleator DAAM2 in patients with androgen insensitivity syndrome. DAAM2 was enriched in the nucleus, where its localization correlated with that of the AR to form actin-dependent transcriptional droplets in response to dihydrotestosterone. DAAM2 AR droplets ranged from 0.02 to 0.06 µm3 in size and associated with active RNA polymerase II. DAAM2 polymerized actin directly at the AR to promote droplet coalescence in a highly dynamic manner, and nuclear actin polymerization is required for prostate-specific antigen expression in cancer cells. Our data uncover signal-regulated nuclear actin assembly at a steroid hormone receptor necessary for transcription.

Persistence of foetal testicular features in patients with defective androgen signalling.

OBJECTIVE: Congenital defects of androgen synthesis or action in 46,XY individuals can result in impaired virilisation, despite the apparent testicular development. In a recent case, report of a young adult with complete androgen insensitivity syndrome (CAIS), tumourous gonadal tissue was shown to express HSD17B3 in Sertoli cells (SCs) and not in Leydig cells (LCs). This expression pattern differs from the typical adult human testis and resembles a foetal mouse testis, suggesting an underlying testicular development and function defect. Here, we investigate the effect of altered androgen signalling in gonads from five 46,XY individuals with defects in androgen synthesis or action. METHODS: Gonadal tissue sections from four patients with CAIS, one with CYP17A1 deficiency, and one control were immunostained for LC developmental and steroidogenic markers. The expression of some of these markers during development was investigated by reanalysing previously published single-cell RNA sequencing (scRNA-seq) data from normal human testicular tissues. RESULTS: All gonadal tissues from the patients show an exclusive expression of HSD17B3 in SCs and an expression of the foetal/immature LC marker DLK1 in a subset of LCs, suggesting an androgen-dependent differentiation defect of adult SCs and LCs. Furthermore, reanalysis of scRNA-seq data reveals an expression of HSD17B3 in foetal and neonatal SCs that is downregulated in adult SCs. CONCLUSIONS: Androgen signalling may affect the differentiation of adults, but possibly not foetal SCs or LCs, and may induce a shift of testosterone production from the tubular compartment in the foetal phase to the interstitial compartment in the adult phase.

Four novel mutations in the androgen receptor gene from Vietnamese patients with androgen insensitivity syndrome.

BACKGROUND: Androgens and androgen receptor (AR) are critical regulators of the masculinization process in male sexual development. The absence of a functioning AR results in the development of the androgen insensitivity syndrome (AIS), a rare disorder of sexual development (DSD) characterized by the external genitalia feminization, gynecomastia, and impaired spermatogenesis. OBJECTIVE: To determine the AR gene mutations associated with male DSD in four unrelated Vietnamese patients. METHODS: To detect the disease-causing mutations, whole exome sequencing (WES) was performed on four patients diagnosed with AIS. Sanger sequencing was then used for validation of the identified mutations. Finally, 12 web-based tools, three-dimensional protein modeling software, and the guidelines issued by the American College of Medical Genetics and Genomics were used to assess the potential pathogenicity of these mutations. RESULTS: Four distinct novel mutations, namely c.1834T > A (p.Cys612Ser), c.2122 C > G (p.Leu708Val), c.2630T > G (p.Phe877Cys), and c.2641 C > A (p.Leu881Met) in the AR gene, were identified in four AIS patients using WES. The in silico analysis results revealed that the Cys612, Leu708, Phe877, and Leu881 sites are important for an appropriate response to androgens of the AR, and mutation at these sites can have adverse effects on the AR functions, androgen-AR interaction, and AR signaling pathway. CONCLUSIONS: WES and in silico analyses strongly suggested that four novel AR mutations are pathogenic and have led to the development of AIS in the four Vietnamese patients under consideration.

Case Report: Low Bone and Normal Lean Mass in Adolescents With Complete Androgen Insensitivity Syndrome.

Introduction: Osteopenia and osteoporosis have been reported in adults with Complete Androgen Insensitivity Syndrome (CAIS). Little is known about changes in bone mineral density (BMD) in adolescents with CAIS and whether it is affected by early gonadectomy. Body composition data have not been reported. Methods: Single-center, retrospective study of CAIS adolescents who underwent dual-energy x-ray absorptiometry (DXA) (Hologic, Horizon A). Body composition is presented as lean and fat mass indices (LMI, FMI). Z-scores for lumbar spine areal BMD (LBMD), total body less head (TBLH), bone mineral content (BMC), LMI, and FMI were calculated using female normative data. Results are expressed as median and min, max. Results: Six females with genetically confirmed CAIS were identified-one with intact gonads and five with history of gonadectomy at 2-11 months. In the subject with intact gonads, LBMD-Z and TBLH BMC-Z were -1.56 and -1.26, respectively, at age 16 years. Among those with gonadectomy, LBMD-Z was -1.8 (-3.59 to 0.49) at age 15.6 years (12-16.8) and decreased in all three subjects who had longitudinal follow-up despite hormone replacement therapy (HRT). Adherence to HRT was intermittent. LMI-Z and FMI-Z were 0.1 (-1.39 to 0.7) and 1.0 (0.22 to 1.49), respectively. Conclusions: These limited data indicate that adolescents with CAIS have bone mass deficit. Further studies are needed to understand the extent of BMD abnormalities and the effect of gonadectomy, especially early in childhood, and to establish the optimal HRT regimen for bone accrual. Data on lean mass are reassuring.

Molecular mechanisms underlying AMH elevation in hyperoestrogenic states in males.

Anti-Müllerian hormone (AMH) is secreted by Sertoli cells of the testes from early fetal life until puberty, when it is downregulated by androgens. In conditions like complete androgen insensitivity syndrome (CAIS), AMH downregulation does not occur and AMH increases at puberty, due in part to follicle-stimulating hormone (FSH) effect. However, other conditions like Peutz-Jeghers syndrome (PJS), characterised by low FSH, also have increased AMH. Because both CAIS and PJS may present as hyperoestrogenic states, we tested the hypothesis that oestradiol (E2) upregulates AMH expression in peripubertal Sertoli cells and explored the molecular mechanisms potentially involved. The results showed that E2 is capable of inducing an upregulation of endogenous AMH and of the AMH promoter activity in the prepubertal Sertoli cell line SMAT1, signalling through ERα binding to a specific ERE sequence present on the hAMH promoter. A modest action was also mediated through the membrane oestrogen receptor GPER. Additionally, the existence of ERα expression in Sertoli cells in patients with CAIS was confirmed by immunohistochemistry. The evidence presented here provides biological plausibility to the hypothesis that testicular AMH production increases in clinical conditions in response to elevated oestrogen levels.

A hemizygous mutation in the androgen receptor gene causes different phenotypes of androgen insensitivity syndrome in two siblings by disrupting the nuclear translocation.

The androgen insensitivity syndrome (AIS) is a congenital disease characterized by androgen resistance due to androgen receptor (AR) gene mutations, resulting in disorders of sex differentiation in 46,XY individuals. However, the underlying mechanisms in the majority of AR variants and the phenotype-genotype correlations are unclear. Here, we identified a p.Y764H variant of the AR gene that results in different phenotypes in a family. Structural analyses revealed that amino acid substitution affected protein properties and spatial conformation, and in vitro, functional studies showed impaired nuclear translocation ability of the mutated protein. Moreover, the extent to which this variant reduced nuclear translocation depends on the dihydrotestosterone (DHT) concentrations. Our results, for the first time, demonstrated a pathogenesis of the p.Y764H mutations in AR resulting in AIS phenotype, and indicated that AIS patients with p.Y764H mutation and preserved gonad might have residual AR activity at high androgen levels, putting patients at risk for pubertal virilization in the future. We provide an in-depth insight into the pathogenesis in AIS based on the amino acid substitution, which may help aid its precise diagnosis, personalized treatment, and organized follow-up to avoid gender dysphoria.

Novel Mutations Segregating with Complete Androgen Insensitivity Syndrome and their Molecular Characteristics.

We analyzed three cases of Complete Androgen Insensitivity Syndrome (CAIS) and report three hitherto undisclosed causes of the disease. RNA-Seq, Real-timePCR, Western immunoblotting, and immunohistochemistry were performed with the aim of characterizing the disease-causing variants. In case No.1, we have identified a novel androgen receptor (AR) mutation (c.840delT) within the first exon in the N-terminal transactivation domain. This thymine deletion resulted in a frameshift and thus introduced a premature stop codon at amino acid 282. In case No.2, we observed a nonsynonymous mutation in the ligand-binding domain (c.2491C>T). Case No.3 did not reveal AR mutation; however, we have found a heterozygous mutation in CYP11A1 gene, which has a role in steroid hormone biosynthesis. Comparative RNA-Seq analysis of CAIS and control revealed 4293 significantly deregulated genes. In patients with CAIS, we observed a significant increase in the expression levels of PLCXD3, TM4SF18, CFI, GPX8, and SFRP4, and a significant decrease in the expression of SPATA16, TSACC, TCP10L, and DPY19L2 genes (more than 10-fold, p < 0.05). Our findings will be helpful in molecular diagnostics of patients with CAIS, as well as the identified genes could be also potential biomarkers for the germ cells differentiation process.

Bone mineral density, body composition and metabolic profiles in adult women with complete androgen insensitivity syndrome and removed gonads using oral or transdermal estrogens.

OBJECTIVES: To assess bone health in adult women with complete androgen insensitivity syndrome (CAIS) and removed gonads compared with age-matched healthy controls. To evaluate the effects of transdermal oestradiol 2 mg or oral estradiol valerate 2 mg on bone, biochemical and clinical characteristics. DESIGN: Cohort study. METHODS: Bone, body composition and anthropometric parameters were assessed in 32 adult CAIS and 32 healthy controls. In 28 cases, CAIS evaluations of metabolic, bone and body composition were performed also after a maximum of 6 years of therapy. RESULTS: Lumbar, femoral and total body bone mineral density (BMD) were significantly lower in those with CAIS when compared with controls. The prevalence of vertebral osteoporosis and osteopenia was significantly higher in the CAIS group (P = 0.038, OR = 9.67, 95% CI: 1.13-82.83 and P = 0.012, OR= 3.85, 95% CI: 1.34-11.16, respectively). Prevalence of femoral osteopenia was significantly higher in the CAIS group (P = 0.0012, OR = 7.93, 95% CI: 2.26-27.9). During follow-up, lumbar BMD significantly increased suggesting a significant effect of treatment on BMD (P = 0.0016), while femoral and total body BMD did not show any significant change. Total body BMD values were positively associated to the duration and route of oestrogen administration and to serum estradiol levels. Transdermal administration of estrogens was associated with better total body BMD in comparison to oral administration. CONCLUSIONS: Our results reinforce the importance of adequate hormonal treatment for women living with CAIS, suggesting a better effect from the transdermal route over the oral route.

Features of the fetal gonad in androgen synthesis in the postpubertal testis are preserved in complete androgen insensitivity syndrome due to a novel genetic splice site donor variant in androgen receptor gene intron 1.

Mutations in the X-linked androgen receptor (AR) gene cause complete androgen insensitivity syndrome (CAIS). CAIS may cause congenital sexual development disorder, which frequently develops into testicular tumors. Here, we describe a novel splice-site intron 1 mutation in AR leading to improper splicing and AR protein absence in CAIS gonads. We characterized a patient's postpubertal gonadal steroidogenic enzyme expression profile. Localization of both CYP11A1 and CYP17A1 enzymes was restricted to both Leydig tumor cells and adjacent to tumor gonadal tissues. Sertoli cells of the CAIS gonad showed abundant HSD17B3 protein, which is an adult Leydig cell marker that enables the conversion of androstenedione to testosterone. Such HSD17B3 expression is typical for fetal-type Sertoli cells in rodents. The postpubertal CAIS gonad of our patient was completely devoid of androgen signaling pathway activity. Plausibly, the postpubertal Leydig cells consisted of two distinct cell populations: postpubertal fetal-type Leydig cells that persisted as androgen-independent cells and immature adult Leydig cells that failed to differentiate. Taken together, in this CAIS postpubertal testis, both Leydig and fetal-type Sertoli cells participated in testosterone production. Our results indicate the importance of molecular analysis as well as the characterization of steroidogenic enzyme profiling in the CAIS patient's gonad.

Non-canonical dimerization of the androgen receptor and other nuclear receptors: implications for human disease.

Nuclear receptors are transcription factors that play critical roles in development, homeostasis and metabolism in all multicellular organisms. An important family of nuclear receptors comprises those members that respond to steroid hormones, and which is subdivided in turn into estrogen receptor (ER) isoforms α and ß (NR3A1 and A2, respectively), and a second subfamily of so-called oxosteroid receptors. The latter includes the androgen receptor (AR/NR3C4), the glucocorticoid receptor (GR/NR3C1), the mineralocorticoid receptor (MR/NR3C2) and the progesterone receptor (PR/NR3C3). Here we review recent advances in our understanding of the structure-and-function relationship of steroid nuclear receptors and discuss their implications for the etiology of human diseases. We focus in particular on the role played by AR dysregulation in both prostate cancer (PCa) and androgen insensitivity syndromes (AIS), but also discuss conditions linked to mutations of the GR gene as well as those in a non-steroidal receptor, the thyroid hormone receptor (TR). Finally, we explore how these recent results might be exploited for the development of novel and selective therapeutic strategies.

Dihydrotestosterone induces minor transcriptional alterations in genital skin fibroblasts of children with and without androgen insensitivity.

Endogenous and exogenous androgens induce masculinization of external genitalia through binding to the androgen receptor (AR). The target genes of androgens in external genitalia remain to be determined, although previous studies have shown that the apolipoprotein D gene (APOD) was significantly upregulated by dihydrotestosterone (DHT), the most potent androgen in humans. In the present study, we performed microarray analysis for genital skin fibroblasts obtained from four boys with buried penis (the control individuals) and a patient with partial androgen insensitivity syndrome (PAIS) due to a hypomorphic mutation in AR (the PAIS patient). We identified 24 transcripts that were upregulated or downregulated by DHT in all samples of control individuals and, to a lesser extent, in the sample of the PAIS patient. Differences between DHT-treated and -untreated samples were small; the results of 24 transcripts did not reach statistical significance. The 24 transcripts included CYP1B1, a gene possibly involved in the development of genital tubercle in mice, and APOD, as well as several genes that have been reported as androgen targets in prostate or other tissues. The results of this study indicate that androgen-mediated masculinization of external genitalia is unlikely to depend on massive transcriptional changes in specific AR target genes. Rather, minor transcriptional changes of several genes, and/or a complex molecular network may play a major role in penile development. Importantly, our data suggest the possible involvement of CYP1B1 in human genital development and confirm the clinical importance of APOD as a biomarker for AR function.

Predicting puberty in partial androgen insensitivity syndrome: Use of clinical and functional androgen receptor indices.

BACKGROUND: PAIS exhibits a complex spectrum of phenotypes and pubertal outcomes. The paucity of reliable prognostic indicators can confound management decisions including sex-of-rearing. We assessed whether external masculinisation score (EMS) at birth or functional assays correlates with pubertal outcome in PAIS patients and whether the EMS is helpful in sex assignment. METHODS: We collected pubertal outcome data for 27 male-assigned PAIS patients, all with confirmed androgen receptor (AR) mutations, including two previously uncharacterized variants (I899F; Y916C). Patients were grouped as follows; EMS at birth <5 and ≥ 5 (EMS in normal males is 12; median EMS in PAIS is 4·7) and pubertal outcomes compared. FINDINGS: Only 6/9 patients (67%) with EMS <5 underwent spontaneous onset of puberty, versus all 18 patients with EMS ≥5 (p = .03). Only 1/6 patients (17%) with EMS <5 developed adult genitalia reaching Tanner stage 4 or 5, versus 11/13 (85%) with EMS ≥5 (p = 0·01). There was no significant difference between the two groups of patients in being prescribed androgen replacement, who reached adult testicular volume ≥ 15 ml, pubic hair Tanner stage 4 or 5, above average adult height, had gynaecomastia, and mastectomy. No correlation was observed between EMS and in vitro AR function. INTERPRETATION: In PAIS with AR mutation, birth EMS is a simple predictor of spontaneous pubertal onset and satisfactory adult genitalia. This provides useful information when discussing the likely options for management at puberty. FUND: European Commission Framework 7 Programme, NIHR Cambridge Biomedical Research Centre, BBSRC DTP.

Childhood Sex-Typed Behavior and Gender Change in Individuals with 46,XY and 46,XX Disorders of Sex Development: An Iranian Multicenter Study.

Disorders of sex development (DSD) are congenital conditions in which the typical genetic and hormonal profiles are affected and thereby the usual process of sexual differentiation. Most of these studies, however, have been conducted in Western countries. In the present study, preschool sex-typed activities of Iranian individuals with DSD and their age-matched non-affected male and female relatives were assessed using the Pre-School Activities Inventory (PSAI) modified for retrospective self-report. A total of 192 individuals participated in our study, including 33 46,XX individuals with congenital adrenal hyperplasia (CAH; M age = 10.36, SD = 5.52), 15 46,XY individuals with complete androgen insensitivity syndrome (CAIS; M age = 19.8, SD = 7.14), and 16 46,XY individuals with 5-alpha reductase deficiency type-2 (5α-RD-2; M age = 17.31, SD = 7.28), as well as one age-matched non-affected male and female relative for each patient. With regard to PSAI scores, male-identifying participants with 5α-RD-2 and male controls reported similar levels of male-typical childhood play. Female-identifying participants with 5α-RD-2 and CAH showed comparable scores: significantly less masculine and more feminine than male controls, but significantly more masculine and less feminine than females with CAIS and female controls. These findings support the role of androgens in the development of sex-typical childhood play behavior, with those being exposed to higher levels of fetal functional androgens expressing more masculine behavior at preschool ages.

Cognitive abilities in women with complete androgen insensitivity syndrome and women with gonadal dysgenesis.

BACKGROUND: Many questions regarding the mechanisms behind sex differences in cognitive abilities are still unanswered. On a group level, men typically outperform women on certain spatial tasks, whereas women perform better on certain tests of memory and verbal ability. The prevailing theories concerning the biological predispositions for these and other differences in behaviour and brain function focus on early and prolonged exposure to sex hormones. There is, however, evidence of direct effects of sex chromosomes on sex-typical behaviour in other species. OBJECTIVES: To study the influence of sex hormones and sex chromosomes on cognition in women with Complete androgen insensitivity (CAIS) and Gonadal dysgenesis (GD). METHODS: Eighteen women with CAIS, 6 women with 46,XYGD, and 7 women with 46,XXGD were compared with age-matched male and female controls on tests of spatial and verbal abilities, memory functions, and emotion recognition. RESULTS: Women with CAIS, XYGD, and XXGD performed similar to female controls on cognitive tasks. However, on a test of emotion recognition, women with XXGD outperformed the other groups, whereas women with CAIS and XYGD performed similar to male controls. CONCLUSION: Our results support theories of androgen effects on cognitive abilities and suggest that factors related to sex chromosomes may influence emotion recognition. Implications of an atypical sex hormone situation and sex chromosome variation are discussed.

Prenatal testosterone and theory of mind development: Findings from disorders of sex development.

Women on average perform better than men on the "Reading the Mind in the Eyes" test (RMET) which is a measure of Theory of Mind (ToM). The aim of this study was to assess whether these sex differences are influenced by differences in prenatal testosterone levels through a study on individuals with Disorders of Sex Development and matched controls. ToM performance was examined using the RMET in female-assigned-at-birth individuals with increased prenatal testosterone exposure (Congenital Adrenal Hyperplasia (CAH) and 5-alpha Reductase type-2 Deficiency (5α-RD-2)), female-assigned-at-birth individuals with testosterone insensitivity (Complete Androgen Insensitivity Syndrome (CAIS)), and their age-matched unaffected male and female relatives. A total number of 158 individuals participated in the study; 19 with 5α-RD-2, 17 with CAH, 18 women with CAIS, 52 matched unaffected men and 52 matched unaffected women. All subgroups were around 20 years of age. Women with CAH scored significantly lower on RMET than control women and CAIS individuals. CAIS individuals scored significantly higher than control men and participants with 5α-RD. Statistically, CAIS individuals' performance on RMET was similar to control women's, women with CAH did not differ significantly from control men and 5α-RD-2 individuals scored significantly lower than control men. These results, which are in line with previous theories, illustrate that performance on the RMET, as an index of ToM, may be influenced by variations in prenatal androgens levels.

Birth Weight in Different Etiologies of Disorders of Sex Development.

CONTEXT: It is well established that boys are heavier than girls at birth. Although the cause of birth weight (BW) difference is unknown, it has been proposed that it could be generated from prenatal androgen action. OBJECTIVE: The aim of the current study was to determine the BW of children with disorders of sex development (DSD) of different etiologies and to evaluate the effects of androgen action on BW. METHODS: Data regarding diagnosis, BW, gestational age, karyotype, and concomitant conditions were collected from the International Disorders of Sex Development (I-DSD) Registry (www.i-dsd). BW standard deviation score was calculated according to gestational age. Cases were evaluated according to disorder classification in I-DSD (i.e., disorders of gonadal development, androgen excess, androgen synthesis, androgen action, nonspecific disorder of undermasculinization groups, and Leydig cell defect). RESULTS: A total of 533 cases were available; 400 (75%) cases were 46,XY, and 133 (25%) cases were 46,XX. Eighty cases (15%) were born small for gestational age (SGA). Frequency of SGA was higher in the 46,XY group (17.8%) than in the 46,XX (6.7%) group (P = 0.001). Mean BW standard deviation scores of cases with androgen excess and androgen deficiency [in disorders of gonadal development, androgen synthesis, and Leydig cell defect groups and androgen receptor gene (AR) mutation-positive cases in disorders of androgen action groups] were similar to normal children with the same karyotype. SGA birth frequency was higher in the AR mutation-negative cases in disorders of androgen action group and in the nonspecific disorders of the undermasculinization group. CONCLUSIONS: BW dimorphism is unlikely to be explained by fetal androgen action per se. 46,XY DSDs due to nonspecific disorders of undermasculinization are more frequently associated with fetal growth restriction, SGA, and concomitant conditions.

Androgen Insensitivity Syndrome at Prepuberty: Marked Loss of Spermatogonial Cells at Early Childhood and Presence of Gonocytes up to Puberty.

Androgen insensitivity syndrome (AIS) is a hereditary condition in patients with a 46,XY karyotype in which loss-of-function mutations of the androgen receptor (AR) gene are responsible for defects in virilization. The aim of this study was to investigate the consequences of the lack of AR activity on germ cell survival and the degree of testicular development reached by these patients by analyzing gonadal tissue from patients with AIS prior to Sertoli cell maturation at puberty. Twenty-three gonads from 13 patients with AIS were assessed and compared to 18 testes from 17 subjects without endocrine disorders. The study of the gonadal structure using conventional microscopy and the ultrastructural characteristics of remnant germ cells using electron microscopy, combined with the immunohistochemical analysis of specific germ cell markers (MAGE-A4 for premeiotic germ cells and of OCT3/4 for gonocytes), enabled us to carry out a thorough investigation of germ cell life in an androgen-insensitive microenvironment throughout prepuberty until young adulthood. Here, we show that germ cell degeneration starts very early, with a marked decrease in number after only 2 years of life, and we demonstrate the permanence of gonocytes in AIS testis samples until puberty, describing 2 different populations. Additionally, our results provide further evidence for the importance of AR signaling in peritubular myoid cells during prepuberty to maintain Sertoli and spermatogonial cell health and survival.

Complete androgen insensitivity syndrome caused by a deep intronic pseudoexon-activating mutation in the androgen receptor gene.

Mutations in the X-linked androgen receptor (AR) gene underlie complete androgen insensitivity syndrome (CAIS), the most common cause of 46,XY sex reversal. Molecular genetic diagnosis of CAIS, however, remains uncertain in patients who show normal coding region of AR. Here, we describe a novel mechanism of AR disruption leading to CAIS in two 46,XY sisters. We analyzed whole-genome sequencing data of the patients for pathogenic variants outside the AR coding region. Patient fibroblasts from the genital area were used for AR cDNA analysis and protein quantification. Analysis of the cDNA revealed aberrant splicing of the mRNA caused by a deep intronic mutation (c.2450-118A>G) in the intron 6 of AR. The mutation creates a de novo 5' splice site and a putative exonic splicing enhancer motif, which leads to the preferential formation of two aberrantly spliced mRNAs (predicted to include a premature stop codon). Patient fibroblasts contained no detectable AR protein. Our results show that patients with CAIS and normal AR coding region need to be examined for deep intronic mutations that can lead to pseudoexon activation.

Identification of an AR Mutation-Negative Class of Androgen Insensitivity by Determining Endogenous AR Activity.

CONTEXT: Only approximately 85% of patients with a clinical diagnosis complete androgen insensitivity syndrome and less than 30% with partial androgen insensitivity syndrome can be explained by inactivating mutations in the androgen receptor (AR) gene. OBJECTIVE: The objective of the study was to clarify this discrepancy by in vitro determination of AR transcriptional activity in individuals with disorders of sex development (DSD) and male controls. DESIGN: Quantification of DHT-dependent transcriptional induction of the AR target gene apolipoprotein D (APOD) in cultured genital fibroblasts (GFs) (APOD assay) and next-generation sequencing of the complete coding and noncoding AR locus. SETTING: The study was conducted at a university hospital endocrine research laboratory. PATIENTS: GFs from 169 individuals were studied encompassing control males (n = 68), molecular defined DSD other than androgen insensitivity syndrome (AIS; n = 18), AR mutation-positive AIS (n = 37), and previously undiagnosed DSD including patients with a clinical suspicion of AIS (n = 46). INTERVENTION(S): There were no interventions. MAIN OUTCOME MEASURE(S): DHT-dependent APOD expression in cultured GF and AR mutation status in 169 individuals was measured. RESULTS: The APOD assay clearly separated control individuals (healthy males and molecular defined DSD patients other than AIS) from genetically proven AIS (cutoff < 2.3-fold APOD-induction; 100% sensitivity, 93.3% specificity, P < .0001). Of 46 DSD individuals with no AR mutation, 17 (37%) fell below the cutoff, indicating disrupted androgen signaling. CONCLUSIONS: AR mutation-positive AIS can be reliably identified by the APOD assay. Its combination with next-generation sequencing of the AR locus uncovered an AR mutation-negative, new class of androgen resistance, which we propose to name AIS type II. Our data support the existence of cellular components outside the AR affecting androgen signaling during sexual differentiation with high clinical relevance.

A Recurrent Germline Mutation in the 5'UTR of the Androgen Receptor Causes Complete Androgen Insensitivity by Activating Aberrant uORF Translation.

A subset of patients with monogenic disorders lacks disease causing mutations in the protein coding region of the corresponding gene. Here we describe a recurrent germline mutation found in two unrelated patients with complete androgen insensitivity syndrome (CAIS) generating an upstream open reading frame (uORF) in the 5' untranslated region (5'-UTR) of the androgen receptor (AR) gene. We show in patient derived primary genital skin fibroblasts as well as in cell-based reporter assays that this mutation severely impacts AR function by reducing AR protein levels without affecting AR mRNA levels. Importantly, the newly generated uORF translates into a polypeptide and the expression level of this polypeptide inversely correlates with protein translation from the primary ORF of the AR thereby providing a model for AR-5'UTR mediated translational repression. Our findings not only add a hitherto unrecognized genetic cause to complete androgen insensitivity but also underline the importance of 5'UTR mutations affecting uORFs for the pathogenesis of monogenic disorders in general.