Residual activity of mutant androgen receptors explains wolffian duct development in the complete androgen insensitivity syndrome

Small Indels in the Androgen Receptor Gene: Phenotype Implications and Mechanisms of Mutagenesis

CONTEXT

Despite high abundance of small indels in human genomes, their precise roles and underlying mechanisms of mutagenesis in Mendelian disorders require further investigation.

OBJECTIVE

To profile the distribution, functional implications, and mechanisms of small indels in the androgen receptor (AR) gene in individuals with androgen insensitivity syndrome (AIS).

METHODS

We conducted a systematic review of previously reported indels within the coding region of the AR gene, including 3 novel indels. Distribution throughout the AR coding region was examined and compared with genomic population data. Additionally, we assessed their impact on the AIS phenotype and investigated potential mechanisms driving their occurrence.

RESULTS

A total of 82 indels in AIS were included. Notably, all frameshift indels exhibited complete AIS. The distribution of indels across the AR gene showed a predominance in the N-terminal domain, most leading to frameshift mutations. Small deletions accounted for 59.7%. Most indels occurred in nonrepetitive sequences, with 15.8% situated within triplet regions. Gene burden analysis demonstrated significant enrichment of frameshift indels in AIS compared with controls (P < .00001), and deletions were overrepresented in AIS (P < .00001).

CONCLUSION

Our findings underscore a robust genotype-phenotype relationship regarding small indels in the AR gene in AIS, with a vast majority presenting complete AIS. Triplet regions and homopolymeric runs emerged as prone loci for small indels within the AR. Most were frameshift indels, with polymerase slippage potentially explaining half of AR indel occurrences. Complex frameshift indels exhibited association with palindromic runs. These discoveries advance understanding of the genetic basis of AIS and shed light on potential mechanisms underlying pathogenic small indel events.

Prevalence, distribution, and risk markers for the development of gonadal germ cell tumors in patients with certain types of disorders of sexual differentiation with Y chromosome - A retrospective study

PURPOSE

To study the prevalence, subtypes, and risk markers for the development of gonadal germ cell tumors (GCT's) among disorders of sexual differentiation (DSD) patients with the Y chromosome.

MATERIALS AND METHOD

Design: A retrospective review of the patient's case records from 2010 to 2020 in Government Medical College, Thiruvananthapuram, India was studied. The study participants included 54 subjects with DSD containing the Y chromosome. Demographic data, external masculinization scoring, associated congenital anomalies, karyotyping, intraoperative findings such as gonadal location and internal genital ducts, histopathology of the resected gonads, and its immunohistochemistry were collected. The prevalence of gonadal GCT's was estimated from paraffin-embedded gonadectomy samples (S = 82).

RESULTS

The median age of occurrence of gonadal GCT's was 18 years. The prevalence of malignant gonadal GCT's was highest among the PAIS group (19.2%) followed by gonadal dysgenesis (15.8% each in MGD and CGD) and least among CAIS (7.7%) (p < 0.01). The most common type of malignant gonadal GCT's in the descending order of frequency was dysgerminoma, seminoma, mixed GCT, and yolk sac tumor. Multivariance logistic analysis showed post-puberty and the presence of congenital anomalies were associated with the occurrence of gonadal GCT's ( P < 0.01).

CONCLUSION

The overall prevalence of gonadal GCT's (malignant and premalignant) among DSD with Y chromosomes is nearly 25%. Dysgerminoma is the most common malignant gonadal GCT's. Age at or above 18 years and the presence of congenital anomalies like renal agenesis, retroperitoneal vascular defects, and congenital diaphragmatic hernia were independent risk markers for the development of gonadal GCT's.

Androgen receptor amplification in mesonephric remnants

Mesonephric remnants (MRs) are embryonic vestiges most commonly found in female pathology specimens from the lateral wall of the cervix. The highly regulated genetic programme of mesonephric duct development has been well characterised in animals based on traditional surgical castration and knockout mouse experiments. However, the process is incompletely understood in humans. MRs are believed to give rise to mesonephric neoplasms, which are rare tumours with uncertain pathophysiology. There is a dearth of molecular studies on mesonephric neoplasms in part due to their rarity. Here, we report the results of next-generation sequencing of MR, which identified amplification of the androgen receptor gene for the first time to the best of our knowledge and discuss the potential implications in the context of the literature.

Whole exome sequencing reveals copy number variants in individuals with disorders of sex development

Complete androgen insensitivity syndrome (CAIS), where 46,XY individuals present as female, is caused by variants in the androgen receptor gene (AR). We analyzed the DNA of a patient with suspected CAIS using a targeted gene sequencing panel and whole exome sequencing (WES) but did not detect any small nucleotide variants in AR. Analysis of WES data using our bioinformatics pipeline designed to detect copy number variations (CNV) uncovered a rare duplication of exon 2 of AR. Using array comparative genomic hybridization, the duplication was found to span 43.6 kb and is predicted to cause a frameshift and loss of AR protein. We confirmed the power of our WES-CNV detection protocol by identifying pathogenic CNVs in FSHR and NR5A1 in previously undiagnosed patients with disorders of sex development. Our findings illustrate the usefulness of CNV analysis in WES data to detect pathogenic genomic changes that may go undetected using only standard analysis protocols.

Molecular basis of androgen insensitivity syndromes

Individuals with complete androgen insensitivity syndrome show a female genital phenotype despite 46, XY gonosomes and the presence of androgen producing testes. This clinical observation indicates the resistance of the body and its cells to androgens like testosterone. At the molecular level, this hormone resistance is caused by hemizygous loss of function mutations in the X-chromosomal androgen receptor (AR) gene. Partial forms of androgen insensitivity syndrome (PAIS) show different degrees of virilisation largely depending on the remaining activity of the AR. Nevertheless, the phenotypic outcome can be variable even in presence of the same mutation and in the same kindred indicating the presence of further influencing factors. Importantly, the majority of clinically diagnosed PAIS individuals do not bear a mutation in their AR gene. A recent assay using the androgen regulated gene apolipoprotein D as biomarker is able to detect androgen insensitivity on the cellular level even in absence of an AR gene mutation. Using this assay a class of AIS without an AR-gene mutation was defined as AIS type II and suggests that unidentified cofactors of the AR are responsible for the PAIS phenotype. Here we outline the scientific progress made from the first clinical definition of AIS over biochemical and molecular characterizations to the concept of AIS type II. This review is based on publications in the PubMed database of the National Institutes of Health using the search terms androgen insensitivity syndrome and androgen receptor mutation.

Identification of two additional novel mutations in the AR gene associated with severe forms of androgen insensitivity syndrome

The Androgen insensitivity syndrome (AIS) in its complete form (CAIS) is a disorder in abnormal male development characterized by a complete female phenotype in a 46,XY individual. The most frequent cause of this disorder is a hemizygous mutation in androgen receptor (AR) gene located in X chromosome. The first aim of this study was to confirm the clinical diagnosis in a series of Tunisian patients with a typical phenotype of CAIS by molecular genetic analysis. The second aim was to determine the AR mutational profile in the local population. The entire coding region and the exon-intron junctions of the AR gene were sequenced in a series of ten patients. AR defects were found in nine patients. Despite the small number of cases, two of the nine identified mutations were novel. The first novel mutation was an 8-bp deletion in exon 1 (c.862_869del) resulting in a frameshift (p.A288Qfs*14). The second was a splice site mutation c.1885 + 1G > T (IVS3 + 1G > T). In this study, genetic testing has confirmed the diagnosis of most CAIS patients and has revealed two novel mechanisms responsible for the pathogenesis of AIS, as well as seven other reported mutations.

Different Clinical Presentations and Management in Complete Androgen Insensitivity Syndrome (CAIS)

Complete androgen insensitivity syndrome (CAIS) is an X-linked recessive genetic disorder resulting from maternally inherited or de novo mutations involving the androgen receptor gene, situated in the Xq11-q12 region. The diagnosis is based on the presence of female external genitalia in a 46, XY human individual, with normally developed but undescended testes and complete unresponsiveness of target tissues to androgens. Subsequently, pelvic ultrasound or magnetic resonance imaging (MRI) could be helpful in confirming the absence of Mullerian structures, revealing the presence of a blind-ending vagina and identifying testes. CAIS management still represents a unique challenge throughout childhood and adolescence, particularly regarding timing of gonadectomy, type of hormonal therapy, and psychological concerns. Indeed this condition is associated with an increased risk of testicular germ cell tumour (TGCT), although TGCT results less frequently than in other disorders of sex development (DSD). Furthermore, the majority of detected tumoral lesions are non-invasive and with a low probability of progression into aggressive forms. Therefore, histological, epidemiological, and prognostic features of testicular cancer in CAIS allow postponing of the gonadectomy until after pubertal age in order to guarantee the initial spontaneous pubertal development and avoid the necessity of hormonal replacement therapy (HRT) induction. However, HRT is necessary after gonadectomy in order to prevent symptoms of hypoestrogenism and to maintain secondary sexual features. This article presents differential clinical presentations and management in patients with CAIS to emphasize the continued importance of standardizing the clinical and surgical approach to this disorder.

Malignant testicular germ cell tumors in postpubertal individuals with androgen insensitivity: prevalence, pathology and relevance of single nucleotide polymorphism-based susceptibility profiling

STUDY QUESTION

What is the prevalence of malignant testicular germ cell tumors (TGCT) and its precursors, (pre-) germ cell neoplasia in situ (GCNIS), in late teenagers and adults who have androgen insensitivity syndrome (AIS) and the impact of an individual's genetic susceptibility to development of TGCT?

SUMMARY ANSWER

No GCNIS or TGCT was diagnosed, but pre-GCNIS was identified in 14 and 10% of complete and partial AIS patients, respectively, and was associated with a higher genetic susceptibility score (GSS), with special attention for KITLG (rs995030) and ATFZIP (rs2900333).

WHAT IS KNOWN ALREADY

Many adult women with AIS decline prophylactic gonadectomy, while data regarding the incidence, pathophysiology and outcomes of TGCT in postpubertal individuals with AIS are lacking. The relevance of genetic factors, such as single nucleotide polymorphisms (SNPs), in predisposing AIS individuals to TGCT is unknown.

STUDY DESIGN, SIZE, DURATION

This multicenter collaborative study on prophylactically removed gonadal tissue was conducted in a pathology lab specialized in germ cell tumor biology.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Material from 52 postpubertal individuals with molecularly confirmed AIS (97 gonadal samples) was included; the median age at surgery was 17.5 (14-54) years. Immunohistochemical studies and high-throughput profiling of 14 TGCT-associated SNPs were performed. The main outcome measures were the prevalence of pre-GCNIS, GCNIS and TGCT, and its correlation with a GSS, developed based on the results of recent genome-wide association studies.

MAIN RESULTS AND ROLE OF CHANCE

The earliest recognizable change preceding GCNIS, referred to as pre-GCNIS, was present in 14% of individuals with complete and 10% of those with partial AIS at a median age of 16 years. No GCNIS or invasive TGCT were found. The median GSS was significantly greater for those with, compared to those without, pre-GCNIS (P = 0.01), with an overlap between groups. Our data suggest important roles for risk alleles G at KITLG (rs995030) and C at ATFZIP (rs2900333), among the 14 studied TGCT-associated SNPs.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

A limited number of cases were included.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that the prevalence of pre-GCNIS in individuals with AIS beyond puberty is around 15%. Genetic susceptibility likely contributes to pre-GCNIS development in AIS but factors related to malignant progression remain unclear. Although data in older patients remain scarce, malignant progression appears to be a rare event, although the natural history of the premalignant lesion remains unknown. Therefore, the practice of routine prophylactic gonadectomy in adults with AIS appears questionable and the patient's preference, after having been fully informed, should be decisive in this matter.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by research grants from the Research Foundation Flanders (FWO) (to M.C.), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq G0D6713N) (to B.B.M. and M.C.) and the European Society for Pediatric Endocrinology (ESPE), granted by Novo Nordisk AB (to J.K.). There are no competing interests.

Perspectives in Pediatric Pathology, Chapter 6. Male Undermasculinization

Normal male development requires three conditions: (1) adequate differentiation of the fetal testis; (2) synthesis and secretion of testicular hormones; and (3) effective action of these hormones on target organs. This requires the combined action of the inhibitory anti-müllerian hormone (AMH, secreted by Sertoli cells) to block the development of the uterus and fallopian tubes from the müllerian duct, together with the trophic stimulus of testosterone (a Leydig cell product), which leads to virilization of the wolffian ducts. Additionally, the development of external genitalia depends on the conversion of testosterone to dihydrotestosterone by the enzyme 5-α-reductase. Failure of any of these mechanisms leads to deficient virilization or the so-called "male pseudohermaphroditism" syndromes.

A novel inactivating mutation of the LH/chorionic gonadotrophin receptor with impaired membrane trafficking leading to Leydig cell hypoplasia type 1

OBJECTIVE

The LH/chorionic gonadotrophin receptor (LHCGR) is a G protein-coupled receptor (GPCR) that plays a central role in male sexual differentiation, regulation of ovarian follicular maturation, ovulation and maintenance of corpus luteum and pregnancy, as well as maintenance of testicular testosterone production. Mutations in the LHCGR gene are very rare. The aim of this work was to study the clinical and molecular characteristics of a rare familial LHCGR mutation.

METHODS

Five affected members of a family, including a phenotypically female, but genotypically male (46,XY), patient with Leydig cell hypoplasia type 1 and four genotypically female siblings with reproductive abnormalities, were studied genetically. Cell trafficking studies as well as signalling studies of mutated receptor were performed.

RESULTS

The five affected patients were all homozygous for a novel mutation in the LHCGR gene, a deletion of guanine in position 1850 (1850delG). This resulted in a frameshift affecting most of the C-terminal intracellular domain. In vitro studies demonstrated that the 1850delG receptor was completely incapable of transit to the cell membrane, becoming trapped within the endoplasmic reticulum. This could not be rescued by small-molecule agonist treatment or stimulated intracellularly by co-expression of a yoked human chorionic gonadotrophin.

CONCLUSIONS

This novel LHCGR mutation leads to complete inactivation of the LHCGR receptor due to trafficking and signalling abnormalities, which improves our understanding of the impact of the affected structural domain on receptor trafficking and function.

A hotspot in the glucocorticoid receptor DNA-binding domain susceptible to loss of function mutation

Glucocorticoids (GCs) are used to treat a variety of inflammatory disorders and certain cancers. However, GC resistance occurs in subsets of patients. We found that EL4 cells, a GC-resistant mouse thymoma cell line, harbored a point mutation in their GC receptor (GR) gene, resulting in the substitution of arginine 493 by a cysteine in the second zinc finger of the DNA-binding domain. Allelic discrimination analyses revealed that the R493C mutation occurred on both alleles. In the absence of GCs, the GR in EL4 cells localized predominantly in the cytoplasm and upon dexamethasone treatment underwent nuclear translocation, suggesting that the ligand binding ability of the GR in EL4 cells was intact. In transient transfection assays, the R493C mutant could not transactivate the MMTV-luciferase reporter. Site-directed mutagenesis to revert the R493C mutation restored the transactivation activity. Cotransfection experiments showed that the R493C mutant did not inhibit the transcriptional activities of the wild-type GR. In addition, the R493C mutant did not repress either the AP-1 or NF-κB reporters as effectively as WT GR. Furthermore, stable expression of the WT GR in the EL4 cells enabled GC-mediated gene regulation, specifically upregulation of IκBα and downregulation of interferon γ and interleukin 17A. Arginine 493 is conserved among multiple species and all human nuclear receptors and its mutation has also been found in the human GR, androgen receptor, and mineralocorticoid receptor. Thus, R493 is necessary for the transcriptional activity of the GR and a hotspot for mutations that result in GC resistance.

Complete androgen insensitivity syndrome in juveniles and adults with female phenotypes

AIM

To report on six cases of the diagnosis and treatment of patients with complete androgen insensitivity syndrome (CAIS) and a review of the relevant published work.

METHODS

A retrospective analysis was performed on the clinical features, diagnosis and treatment of a total of six patients with CAIS who were admitted to our hospital between September 1985 and June 2012. All surgical patients were examined for sex chromosomes and sex hormone levels pre- and postoperatively, respectively, and underwent lower abdominal B ultrasounds and pathological examinations among other tests.

RESULTS

Five of the patients were treated with castration, one patient aged 5 years was treated conservatively Tissue from surgical resections showed normal testicular tissue that comprised Leydig cells and Sertoli cells, and pathological examinations showed no sign of testicular cancer. Following corrective operations, postoperative complications, such as female secondary sexual characteristics, stagnation and osteoporosis, have not developed. Sex hormone level ratio changed significantly after being treated with castration compared with preoperative levels; mainly testosterone and estrogen decreased significantly (P < 0.05), while luteinizing hormone and follicle-stimulating hormone significantly increased (P < 0.05). However, prolactin did not change significantly (P > 0.05).

CONCLUSION

The study show that removal of the testes in CAIS patients after puberty is safe and reliable. Meanwhile, it is essential to provide a hormone drug after being treated with castration. Further studies are needed to evaluate the safety and the quality of life for CAIS patients.

Wolffian duct development

The Wolffian ducts (WDs) are the progenitors of the epididymis, vas deferens and seminal vesicles. They form initially as nephric ducts that acquire connection to the developing testis as the mesonephros regresses. The development of the WDs is dependent on androgens. Conventionally, the active androgen is believed to be testosterone delivered locally rather than via the systemic circulation. However, recent studies in marsupials show that 5α-reduced steroids are essential and that these can induce virilisation even when they are delivered via the systemic circulation. The development of the WDs involves an interplay between the duct epithelium and underlying mesenchyme; androgen receptors in both the epithelium and mesenchyme are needed. The epidermal growth factor and epidermal growth factor receptor may play a role, possibly via activation of androgen receptor. The formation of the epididymis involves a complex morphogenetic program to achieve the normal pattern of coiling, formation of septae, and regional functional differentiation. In part, this process may be mediated by inhibin beta A as well as by genes from the HOX cluster. Whilst the development of the WD is androgen dependent, it is clear that there is a complex interplay between androgens, genes and growth factors in the tissues that leads to the formation of the complex anatomy of the male reproductive duct system in the adult.

Testicular histological and immunohistochemical aspects in a post-pubertal patient with 5 alpha-reductase type 2 deficiency: case report and review of the literature in a perspective of evaluation of potential fertility of these patients

BACKGROUND

Testicular morphology and immunohistochemical studies have never been reported in genetically documented adult patients with 5 alpha-reductase type 2 deficiency (5α-R2 deficiency).

CASE PRESENTATION

We describe the testicular histopathology of a 17-year-old XY subject with 5α-R2 deficiency caused by the recurrent homozygous Gly115Asp loss of function mutation of the SRD5A2 gene.We also performed an immunohistochemical analysis in order to further study the relationship between seminiferous tubules structure, Sertoli cell differentiation and androgenic signaling impairment in this case. We thus evaluated the testicular expression of the anti-Müllerian hormone (AMH), androgen receptor (AR) and 3β-hydroxysteroid dehydrogenase (3βHSD). Histological analysis revealed a heterogeneous aspect with a majority (92%) of seminiferous tubules (ST) presenting a mature aspect but containing only Sertoli cells and devoid of germ cells and spermatogenesis. Focal areas of immature ST (8%) were also found. Testicular AR and 3βHSD expression were detected in adult male control, 5α-R2 deficiency and CAIS subjects. However, AMH expression was heterogeneous (detectable only in few AR negative prepubertal ST, but otherwise repressed) in the 5α-R2 deficiency, conversely to normal adult testis in which AMH was uniformly repressed and to an adult CAIS testis in which AMH was uniformly and strongly expressed.

CONCLUSION

Intratesticular testosterone can repress AMH by itself, independently of its metabolism into dihydrotestosterone. We also compare our results to the few post pubertal cases of 5α-R2 deficiency with available histological testicular description, reported in the literature. We will discuss these histological findings, in the more general context of evaluating the fertility potential of these patients if they were raised as males and were azoospermic.

Complete androgen insensitivity syndrome: factors influencing gonadal histology including germ cell pathology

Patients with complete androgen insensitivity syndrome are at an increased risk for the development of gonadal germ cell cancer. Residual androgen receptor (AR) activity and abnormal gonadal location may influence the survival of atypical germ cells and the development of other histopathological features. To assess this, we evaluated 37 gonads from 19 patients with complete androgen insensitivity (ranging in age from 3 months to 18 years). Histological abnormalities were examined using hematoxylin and eosin-stained sections and sections stained for POU5F1 and KITLG, markers of early changes in germ cells at risk for malignant transformation. Hamartomatous nodules (HNs), Leydig cell hyperplasia (LCH), decreased germ cells, tubular atrophy and stromal fibrosis were more pronounced as age increased (P<0.001). Expected residual AR activity acted as a positive predictor only for non-malignant germ cell survival in (post)pubertal patients (P<0.05). Immunohistochemical studies indicated that delayed maturation of germ cells was present in three patients, whereas intermediate changes that occurred between delayed maturation and intratubular germ cell neoplasia, designated pre-intratubular germ cell neoplasia, were identified in four cases. Intratubular germ cell neoplasia was observed in one patient. Neither POU5F1 nor KITLG expression was dependent on expected residual AR activity. An independent effect of inguinal versus abdominal position of the gonads was difficult to assess because inguinal gonads were present primarily in the youngest individuals. In conclusion, many histological changes occur increasingly with age. Expected residual AR activity contributes to better survival of the general germ cell population in (post)pubertal age; however, it did not seem to have an important role in the survival of the germ cells at risk for malignant transformation (defined by POU5F1 positivity and KITLG overexpression) in complete androgen insensitivity. Comparison of the high percentage of patients in our study that were carrying germ cells with delayed maturation or pre-intratubular germ cell neoplasia with previously reported cumulative risk of tumor development in adult patients indicates that not all such precursor lesions in complete androgen insensitivity will progress to invasive germ cell cancer.

AR and SRD5A2 gene mutations in a series of 51 Turkish 46,XY DSD children with a clinical diagnosis of androgen insensitivity

46,XY disorders of sex development (DSD) are caused by disorders of gonadal development, androgen biosynthesis and receptor (AR) defects. Although, clinical/biochemical features help in distinguishing specific aetiologies, there are overlaps which necessitate molecular analyses for the definitive diagnosis. To test precision of our clinical diagnosis of androgen insensitivity (AIS) by analysing AR and then SRD5A2 genes, patients were recruited at Marmara University Hospital and molecular analyses were performed at Vall d'Hebron Research Institute. Among 101 46,XY DSD patients, 46 index and five siblings (nine complete, 42 partial) with clinical/biochemical data suggestive of AIS and stimulated T/DHT ratio <25 were selected. AR and then SRD5A2 genes were sequenced. We detected AR mutations in 11 patients [seven index and four siblings (22% of all and 15% of index patients)] and SRD5A2 mutations in six [five index and one sibling (12% of all and 11% of index)]. AR mutation detection rate was 6/9 in all CAIS and 4/7 in the index (67 and 57% respectively) and 5/42 in all PAIS and 3/40 in the index (12 and 7.5% respectively). The eight mutations detected in the AR gene were as follows: p.Q58L, p.P392S, p.R609K, p.R775H, p.R856H, p.A871A, p.V890M and p.F892L, with p.A871A and p.F892L being novel. Further six patients had SRD5A2 mutations which were as follows: p.L73WfsX59, p.Y91H, p.R171S and p.G196S, the first being novel. Hormonal data in those with AR mutations, SRD5A2 mutations and no mutations were not statistically different. In conclusion, a significant proportion of children with presumptive diagnosis of AIS has a normal AR gene. The less severe the phenotype, the less likely is the chance of demonstrating a mutation. Furthermore, a significant number of children with presumptive diagnosis of AIS have mutations in SRD5A2 gene and are clinically and biochemically indistinguishable from AIS.

Androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS) is a disorder caused by a mutation of the gene encoding the androgen receptor (AR; Xq11-q12). The prevalence of AIS has been estimated to be one case in every 20,000 to 64,000 newborn males for the complete syndrome (CAIS), and the prevalence is unknown for the partial syndrome (PAIS). The symptoms range from phenotypically normal males with impaired spermatogenesis to phenotypically normal women with primary amenorrhea. Various forms of ambiguous genitalia have been observed at birth. The diagnosis is confirmed by determining the exact mutation in the AR gene. PAIS individuals require precise diagnosis as early as possible so that the sex can be assigned, treatment can be recommended, and they can receive proper genetic counseling. After birth, differential diagnosis should be performed using other forms of abnormal sexual differentiation of primary amenorrhea. The treatment of AIS is based on reinforcement sexual identity, gonadectomy planning, and hormone replacement therapy. The prognosis for CAIS is good if the testicular tissue is removed at the appropriate time. For PAIS, the prognosis depends on the ambiguity of the genitalia and physical and psychosocial adjustment to the assigned sex.

Evidence for DNA-binding domain--ligand-binding domain communications in the androgen receptor

DNA binding as well as ligand binding by nuclear receptors has been studied extensively. Both binding functions are attributed to isolated domains of which the structure is known. The crystal structure of a complete receptor in complex with its ligand and DNA-response element, however, has been solved only for the peroxisome proliferator-activated receptor γ (PPARγ)-retinoid X receptor α (RXRα) heterodimer. This structure provided the first indication of direct interactions between the DNA-binding domain (DBD) and ligand-binding domain (LBD). In this study, we investigated whether there is a similar interface between the DNA- and ligand-binding domains for the androgen receptor (AR). Despite the structural differences between the AR- and PPARγ-LBD, a combination of in silico modeling and docking pointed out a putative interface between AR-DBD and AR-LBD. The surfaces were subjected to a point mutation analysis, which was inspired by known AR mutations described in androgen insensitivity syndromes and prostate cancer. Surprisingly, AR-LBD mutations D695N, R710A, F754S, and P766A induced a decrease in DNA binding but left ligand binding unaffected, while the DBD-residing mutations K590A, K592A, and E621A lowered the ligand-binding but not the DNA-binding affinity. We therefore propose that these residues are involved in allosteric communications between the AR-DBD and AR-LBD.

Molecular biology of androgen insensitivity

Androgen insensitivity syndrome (AIS) is the most common specific cause of 46,XY disorder in sex development. The androgen signaling pathway is complex but so far, the only gene linked with AIS is the androgen receptor (AR). Mutations in the AR are found in most subjects with complete AIS but in partial AIS, the rate has varied 28-73%, depending on the case selection. More than 400 different mutations in AR leading to AIS have been reported. Most mutations are missense substitutions located in the ligand binding domain of the receptor. However, when systematically screened, a substantial amount of mutations can be detected also in the N-terminal domain encoded by exon 1. Within this exon lie two trinucleotide, CAG and GGN repeat regions which are polymorphic in length. Their role in androgen insensitivity is somewhat unclear. Recent advances in protein modeling have resulted in better understanding of the mechanism of known AR mutations.

Pubertal androgenization and gonadal histology in two 46,XY adolescents with NR5A1 mutations and predominantly female phenotype at birth

OBJECTIVE

Most patients with NR5A1 (SF-1) mutations and poor virilization at birth are sex-assigned female and receive early gonadectomy. Although studies in pituitary-specific Sf-1 knockout mice suggest hypogonadotropic hypogonadism, little is known about endocrine function at puberty and on germ cell tumor risk in patients with SF-1 mutations. This study reports on the natural course during puberty and on gonadal histology in two adolescents with SF-1 mutations and predominantly female phenotype at birth.

DESIGN AND METHODS

Clinical and hormonal data and histopathological studies are reported in one male and one female adolescent with, respectively, a nonsense mutation (c.9T>A, p.Tyr3X) and a deletion of the first two coding exons (NCBI36/hg18 Chr9:g.(126306276-126307705)_(126303229-126302828)del) of NR5A1, both predicted to fully disrupt gene function.

RESULTS

LH and testosterone concentrations were in the normal male range, virilization was disproportionate to the neonatal phenotype. In the girl, gonadectomy at 13 years revealed incomplete spermatogenesis and bilateral precursor lesions of testicular carcinoma in situ. In the boy, at the age of 12, numerous germ cells without signs of malignancy were present in bilateral testicular biopsy specimen.

CONCLUSIONS

In SF-1 mutations, the neonatal phenotype poorly predicts virilization at puberty. Even in poorly virilized cases at birth, male gender assignment may allow spontaneous puberty without signs of hypogonadotropic hypogonadism, and possibly fertility. Patients with SF-1 mutations are at increased risk for malignant germ cell tumors. In case of preserved gonads, early orchidopexy and germ cell tumor screening is warranted. The finding of premalignant and/or malignant changes should prompt gonadectomy or possibly irradiation.

Male gender identity in complete androgen insensitivity syndrome

Women and girls with complete androgen insensitivity syndrome (CAIS) invariably have a female typical core gender identity. In this case report, we describe the first case of male gender identity in a CAIS individual raised female leading to complete sex reassignment involving both androgen treatment and phalloplasty. CAIS was diagnosed at age 17, based on an unambiguously female phenotype, a 46,XY karyotype, and a 2660delT androgen receptor (AR) gene mutation, leading to a premature stop in codon 807. Bilateral gonadectomy was performed but a short period of estrogen treatment induced a negative emotional reaction and treatment was stopped. Since the age of 3, childhood-onset cross gender behavior had been noticed. After a period of psychotherapy, persisting male gender identity was confirmed. There was no psychiatric co-morbidity and there was an excellent real life experience. Testosterone substitution was started, however without inducing any of the desired secondary male characteristics. A subcutaneous mastectomy was performed and the patient received phalloplasty by left forearm free flap and scrotoplasty. Testosterone treatment was continued, without inducing virilization, and bone density remained normal. The patient qualifies as female-to-male transsexual and was treated according to the Standards of Care by the World Professional Association for Transgender Health with good outcome. However, we do not believe that female sex of rearing as a standard procedure should be questioned in CAIS. Our case challenges the role of a functional AR pathway in the development of male gender identity.

Characterization of androgen receptor structure and nucleocytoplasmic shuttling of the rice field eel

Androgen receptor (AR) plays a critical role in prostate cancer and male sexual differentiation. We have identified AR from a primitive vertebrate with a sex reversal characteristic, the rice field eel. AR of this species (eAR) is distinct from human AR, especially in the ligand binding domain (LBD), and its expression in gonads shows an increasing tendency during gonadal transformation from ovary via ovotestis to testis. eAR has a restricted androgen-dependent transactivation function after a nuclear translocation upon dihydrotestosterone exposure. A functional nuclear localization signal was further identified in the DNA binding domain and hinge region. Although nuclear export is CRM1-independent, eAR has a novel nuclear export signal, which is negatively charged, indicating that a nuclear export pathway may be mediated by electrostatic interaction. Further, our studies have identified critical sequences for ligand binding in the C terminus. A structure of three α-helices in the LBD has been conserved from eels to humans during vertebrate evolution, despite a distinct amino acid sequence. Mutation analysis confirmed that the LBD is essential for dihydrotestosterone-induced nuclear import of eAR and following transactivation function in the nucleus. In addition, eAR interacts with both Sox9a1 and Sox9a2, and their interaction regulates transactivation of eAR. Our data suggest that the primitive species conserves and especially acquires key novel domains, the nuclear export signal and LBD, for the eAR function in spite of a rapid sequence evolution.

Familial complete androgen insensitivity syndrome with prostatic tissue and seminal vesicles

INTRODUCTION

Complete androgen insensitivity syndrome (CAIS) is a rare androgen receptor function disorder where phenotypic female has a male genotype. They mostly present as bilateral inguinal hernias containing testes. Uterus and cervix are absent.

MATERIALS AND METHODS

The authors present a case of CAIS in a 22-year-old female where the presence of testes, prostatic tissue and seminal vesicles was confirmed by ultrasonography, hormonal analysis, operative findings and histopathological study. She was second of the two sisters and her elder sister was also diagnosed with CAIS.

CONCLUSION

High levels of testosterone seen in CAIS can stimulate Wolffian duct development/differentiation. Gonadectomy is advisable in such patients to avoid future neoplastic changes.

Complete androgen insensitivity syndrome: diagnosis and management

Complete androgen insensitivity syndrome (CAIS) is an X-linked genetic disorder affecting 46,XY individuals, characterized by the loss of function of the androgen receptor gene resulting in complete peripheral androgen resistance. Patients have a nonambiguous female phenotype with normal female external genitalia. Gonads are undescended testes (either intra-abdominal or inguinal), there is no uterus and the length of the vagina is usually very short. Gender identity is always female. This review focuses on the importance of accurate diagnosis of CAIS versus partial androgen insensitivity syndrome and other disorders of sex development by genotyping the androgen receptor, and raises issues of the optimal management of these patients. In the era of the Consensus Statement on Management of Intersex Disorders, we provide new insights into CAIS screening, surgical management of the gonads (balancing between hormonal production and malignancy risk) and of vaginal adequacy, and the ethics concerned with the disclosure to patients and their families.

Comparison of the molecular consequences of different mutations at residue 754 and 690 of the androgen receptor (AR) and androgen insensitivity syndrome (AIS) phenotype

OBJECTIVE

Androgen insensitivity syndrome (AIS) is associated with mutations throughout the androgen receptor (AR) gene. Different mutations at the same codon have been identified in individuals with various phenotypes suggesting the nature of the codon substituted may influence the degree of AIS. We investigated if phenotype could be predicted by comparing the functionality of AR mutations with those at the same codon of known phenotype.

PATIENTS

We identified patients from the Cambridge Disorders of Sex Development Database with the AR substitutions: Phe754Ser with microphallus without hypospadias and Asp690Val with complete AIS. Mutations Phe754Leu, Phe754Val and Asp690deletion (Asp690del) have previously been reported to be associated with different degrees of AIS.

DESIGN

We characterized the functional properties of Phe754Ser, Phe754Leu, Phe754Val, Asp690Val and Asp690del receptor mutants in vitro and used the crystal structure of the AR ligand binding domain to model the mutations.

RESULTS

The receptor mutants Phe754Ser, Phe754Leu and Phe754Val bound androgen with decreasing affinity, while Asp690Val showed reduced affinity compared to Asp690del. A similar pattern of reduced activation was seen on androgen responsive elements. We suggest how the mutations could affect AR structure, resulting in the observed phenotypes.

CONCLUSIONS

The relative functional properties of Phe754 and Asp690 mutant AR receptors correlate broadly with their specific phenotypes. Therefore, comparing the molecular consequences of novel mutations with others at the same codon may be a useful aid to AIS patient management, particularly for sex of rearing decisions when prediction of functionality is important.

Disorders of sex development: update on the genetic background, terminology and risk for the development of germ cell tumors

BACKGROUND

Considerable progress has been made on genetic mechanisms involved in disorders of sex development and on tumor formation in dysgenetic gonads. Clinical and psychological outcome of patients are, as far as evaluated, unsatisfactory at present. Guidelines are emerging in order to optimize long-term outcome in the future.

DATA SOURCES

The information obtained in this review is based on recent original publications and on the experience of our multidisciplinary clinical and research group.

RESULTS

This review offers an update on our knowledge concerning gene mutations involving in disorders of sex development, on the renewed nomenclature and classification system, and on the mechanisms of tumor development in patients.

CONCLUSIONS

The consensus meeting on disorders of sex development has renewed our interest in clinical studies and long-term outcome of patients. Psychological research emphasizes the importance to consider male gender identity wherever possible in cases of severe undervirilization. Patient advocacy groups demand a more conservative approach regarding gonadectomy. Medical doctors, scientists and governmental instances are increasingly interested in the set-up of international research collaborations. As a consequence, it is expected that new guidelines for the optimal care of patients will be proposed in the coming years.

New insights into the role of androgens in wolffian duct stabilization in male and female rodents

Androgen-mediated wolffian duct (WD) development is programmed between embryonic d 15.5 (e15.5) and 17.5 in male rats, and WD differentiation has been shown to be more susceptible to reduced androgen action than is its initial stabilization. We investigated regulation of these events by comparing fetal WD development at e15.5-postnatal d0 in male and female androgen receptor knockout mice, and in rats treated from e14.5 with flutamide (100 mg/kg/d) plus di-n(butyl) phthalate (500 mg/kg/d) to block both androgen action and production, testosterone propionate (20 mg/kg/d) to masculinize females, or vehicle control. In normal females, WD regression occurred by e15.5 in mice and e18.5 in rats, associated with a lack of epithelial cell proliferation and increased apoptosis, disintegration of the basement membrane, and reduced epithelial cell height. Exposure to testosterone masculinized female rats including stabilization and partial differentiation of WDs. Genetic or chemical ablation of androgen action in males prevented masculinization and induced WD regression via similar processes to those in normal females, except this occurred 2-3 d later than in females. These findings provide the first evidence that androgens may not be the only factor involved in determining WD fate. Other factors may promote survival of the WD in males or actively promote WD regression in females, suggesting sexually dimorphic differences in the preprogrammed setup of the WD.

Phenotypic variability in 17beta-hydroxysteroid dehydrogenase-3 deficiency and diagnostic pitfalls

OBJECTIVE

17beta-hydroxysteroid dehydrogenase type 3 isoenzyme (17beta-HSD3) is required to produce testosterone for male sex differentiation. Mutations in the HSD17B3 gene cause 17betaHSD3 deficiency and result in XY sex reversal of varying degree. We report the phenotypes of 14 subjects with 17betaHSD3 deficiency in relation to sex of rearing, androgen production, and HSD17B3 mutations.

DESIGN

Cases were identified through the Cambridge Disorders of Sex Development Database where detailed clinical information was recorded, results of hCG stimulation tests were available, and HSD17B3 mutation was identified.

RESULTS

Fourteen subjects from seven pedigrees (four consanguineous) had the following seven mutations: A56T, N130S, E215D, S232L, C268Y, V205E, and a novel mutation M197K. XY sex reversal was classified as complete in 10 infants at birth. Inguinal masses suggestive of androgen insensitivity syndrome (AIS) occurred in five infants. Contrasexual virilization reminiscent of 5alpha-reductase deficiency occurred in four subjects at puberty. The median (range) testosterone : androstenedione (T/A) ratio after a short hCG stimulation test was 0.32 (0.12-3.4). The S232L mutation identified in three affected family members caused isolated, severe hypospadias in one member who was raised male; virilization occurred despite in vitro studies showing an inactive mutant enzyme. Ratios of T/A in this pedigree were more than 0.8.

CONCLUSION

XY sex reversal is sufficiently variable in 17betaHSD3 deficiency to cause problems in accurate diagnosis, particularly in distinguishing it from AIS. It should be considered in undervirilized male infants with normal Wolffian duct structures, absent Müllerian ducts, and normal adrenal steroid biosynthesis; or when an assigned female subject virilizes at puberty. Elevated hCG-stimulated T/A ratio may occur, and sex of rearing may not be concordant within affected families with the same HSD17B3 mutation. The T/A ratio, mutation analysis and functional analysis of the mutant enzyme taken in isolation, respectively, may not conclusively establish a diagnosis of 17betaHSD3 deficiency in undervirilized male subjects; the reasons for these discrepancies remain unknown.

Complete androgen insensitivity without Wolffian duct development: the AR-A form of the androgen receptor is not sufficient for male genital development

BACKGROUND

The androgen receptor (AR) is essential for the differentiation of male external and internal genitalia. It is normally present in two forms, a full-length form B and an N-terminal truncated form A with still unknown function. Mutations in the AR gene cause androgen insensitivity syndrome (AIS), which is divided into subgroups according to the degree of undermasculinization. Patients with completely female external genitalia are classified as complete AIS (CAIS). However, a recent study has shown that some CAIS patients have signs of internal male genital differentiation due to missense mutations that show some degree of residual function.

OBJECTIVE

We aimed to study the expression of the different forms of the AR in two CAIS patients in relation to the development of male internal genital structures. One patient had a mutation (L7fsX33) that affects only the full-length AR-B form of the AR, whereas the other had a nonsense mutation (Q733X) affecting both isoforms.

MEASUREMENTS AND RESULTS

We thoroughly analysed internal genitalia at surgery and by histological examination. No signs of Wolffian duct (WD) development were present in any of the patients. Western blotting of proteins from gonadal and genital skin fibroblasts was performed with AR antibodies directed against different AR epitopes. The N-terminally truncated A form was expressed in normal amounts in the patient with the L7fsX33 mutation while no AR was detected in the other patient.

CONCLUSION

The presence of the AR-A form does not seem to be sufficient for WD maintenance and differentiation.

Regulation of Wolffian Duct Development

Wolffian ducts (WDs) are the embryonic structures that form the male internal genitalia. These ducts develop in both the male and female embryo. However, in the female they subsequently regress, whereas in the male they are stabilised by testosterone. The WDs then develop into separate but contiguous organs, the epididymis, vas deferens and seminal vesicles. Recently, considerable progress has been made in identifying genes that are involved in these different stages of development which is described in this review. In addition, WD development in (atypical forms of) cystic fibrosis and intersex disorders, such as the complete androgen insensitivity syndrome, 17beta-hydroxysteroid dehydrogenase deficiency and LH-receptor defects, is discussed. The apparent increase in male reproductive tract disorders is briefly discussed from the perspective of the potential endocrine-disrupting effects of the numerous chemicals in the environment to which the developing male foetus can be exposed.

Androgen receptor gene mutations in androgen insensitivity syndrome cause distinct patterns of reduced activation of androgen-responsive promoter constructs

Assessment of quantitative impairment of reporter gene activation is an important strategy proving pathogenetic relevance of androgen receptor (AR)-gene mutations in androgen insensitivity syndrome (AIS). We hypothesized the additional existence of mutation-specific patterns of reduced target gene activation. Four AR-gene mutations causing AIS, L712F, M780I, R855H, and V866M, respectively, were recreated in an AR-expression plasmid. Activation of three structurally different androgen-dependent promoters (MMTV, (ARE)2TATA, and GRE-OCT) was measured in transfected CHO-cells in response to dihydrotestosterone (DHT), testosterone, androstenedione and stanozolol (S). V866M showed the lowest activity across all conditions. R855H exhibited strikingly high activation of MMTV in response to DHT. M780I showed markedly low activation of (ARE)2TATA by S. L712F demonstrated high activation of GRE-OCT. In essence, each mutation was characterized in this model by a specific pattern of reduced reporter gene activation. Our AR crystal structure analyses showed that L712 and M780 may cause distinct alterations of AR-ligand- and AR-coregulator interaction interfaces supporting the experimental observations. Our data support the hypothesis that mutations of the AR-gene in AIS induce mutation-specific patterns of reduced promoter activation in vitro. Considering the diversity of natural androgen-regulated promoters, mutation-specific differences of androgen response patterns may be of relevance in vivo and consequently may influence the AIS-phenotype. Assessment of transactivation patterns in vitro may be an interesting concept to extend functional description of AR-gene mutations in AIS.

Germ cell tumors in the intersex gonad: old paths, new directions, moving frontiers

The risk for the development of germ cell tumors is an important factor to deal with in the management of patients with disorders of sex development (DSD). However, this risk is often hard to predict. Recently, major progress has been made in identifying gene-products related to germ cell tumor development (testis-specific protein-Y encoded and octamer binding transcription factor 3/4) and in recognizing early changes of germ cells (maturation delay, preneoplastic lesions, and in situ neoplasia). The newly recognized "undifferentiated gonadal tissue" has been identified as a gonadal differentiation pattern bearing a high risk for the development of gonadoblastoma. It is expected that the combination of these findings will allow for estimation of the risk for tumor development in the individual patient (high risk/intermediate risk/low risk). This article reviews the recent literature regarding the prevalence of germ cell tumors in patients with DSD. Some major limitations regarding this topic, including a confusing terminology referring to the different forms of intersex disorders and unclear criteria for the diagnosis of malignant germ cells at an early age (maturation delay vs. early steps in malignant transformation) are discussed. Thereafter, an overview of the recent advances that have been made in our knowledge of germ cell tumor development and the correct diagnosis of early neoplastic lesions in this patient population is provided. A new classification system for patients with DSD is proposed as a tool to refine our insight in the prevalence of germ cell tumors in specific diagnostic groups.

Sexualmedizinische Aspekte bei Intersexsyndromen

Disorders of somatosexual development that lead to ambiguous genitalia occur in one from 3,000-5,000 newborns. Parents and health care professionals are confronted with a number of crucial questions: to what sex should the child be assigned, what is the appropriate treatment in terms of hormonal and surgical interventions, when and how should these take place, and what impact do they have on the development of gender identity (GI), psychosexual well-being and fertility? This paper reviews the etiology, treatment and outcome in terms of GI and sexual health for the following syndromes: congenital adrenal hyperplasia (CAH), complete and partial androgen insensitivity (cAIS, pAIS), and pure and mixed gonadal dysgenesis (pGD, mGD). Emphasis is focussed on the current discussion involving the timing and extent of genital surgery. Finally, a procedure is introduced that covers the sexual-medical needs of patients, parents and health care professionals.

Changes in Gene Expression during Wolffian Duct Development

BACKGROUND

Wolffian ducts (WDs) are the embryonic precursors of the male reproductive tract. Their development is induced by testosterone, which interacts with the androgen receptor (AR). The molecular pathways underlying androgen-dependent WD development are largely unknown. We aimed to identify AR target genes important in this process.

METHODS

RNA was isolated from rat WDs at E17.5 and E20.5. Affymetrix GeneChip expression arrays were used to identify transcripts up- or downregulated more than 2-fold. Regulation of seven transcripts was confirmed using quantitative PCR.

RESULTS

Transcripts from 76 known genes were regulated, including modulators of insulin-like growth factor and transforming growth factor-beta signalling. By controlling these modulators, androgens may indirectly affect growth factor signalling pathways important in epithelial-mesenchymal interactions and organ development. Caveolin-1, also upregulated, may play a role in modifying as well as mediating AR signalling. Differentiation of WD epithelium and smooth muscle, innervation and extracellular matrix synthesis were reflected in regulation of other transcripts. Several genes were previously suggested to be regulated by androgens or contained functional or putative androgen/glucocorticoid response elements, indicating they may be direct targets of androgen signalling.

CONCLUSION

Our results suggest novel cohorts of signals that may contribute to androgen-dependent WD development and provide hypotheses that can be tested by future studies.

Testicular development in the complete androgen insensitivity syndrome

The complete androgen insensitivity syndrome (CAIS), caused by mutations in the androgen receptor (AR) gene, is associated with abnormal testicular development and an increased risk of germ cell malignancy. Previous histological studies in CAIS have selected patients purely on the basis of clinical diagnosis and were mostly based on small numbers, many of whom were post-pubertal. Here, we present 44 cases of CAIS, each with molecular pathological confirmation of an AR mutation. The median age at gonadectomy was 5.5 years (5.5; IQR 1-13). We have been able, therefore, to investigate testicular development in infancy, childhood and puberty, and estimate the incidence of premalignant change in this series. In addition, we have investigated whether the presence of epididymides and/or vasa deferentia in CAIS, previously shown to be associated with residual activity of mutant ARs, is related to a particular testicular phenotype. Epididymides/vasa deferentia were present in 36% of cases and these patients showed varying degrees of seminiferous tubule maturation at puberty above those without epididymides/vasa deferentia (p = 0.003). There were no other histological differences between these patient groups. In both groups, features of testicular degeneration and dysgenesis were present and germ cell development was delayed, with prolonged expression of the gonocyte markers, placental-like alkaline phosphatase and activator protein-2gamma. Germ cell numbers rapidly declined after the first year of life (R(2) = 0.42). Only two cases of carcinoma in situ were identified in our study and both patients were postpubertal (17 and 53 years). From these results and the literature, we conclude that the risk of premalignant change in germ cells is low before and during puberty. Patients can be advised, therefore, that gonadectomy can be delayed to allow for a natural puberty, with low risk of malignant transformation. Our study only included one patient over 18 years, so we cannot comment on the risk of malignant transformation in later life.

Gender dysphoria and gender change in androgen insensitivity or micropenis

This review article answers three questions relevant to the medical management and care of individuals born with complete androgen insensitivity syndrome (CAIS), partial androgen insensitivity syndrome (PAIS), or a micropenis: (1) Do any of these individuals reassign themselves from their initial gender assignment? (2) Do more reassign than the ones who do not? (3) Is there evidence of gender dysphoria in those who do not self-initiate reassignment? Reviewed were all articles on CAIS, PAIS, and micropenis cited in K. J. Zucker (1999) plus articles published through 2004. There were no documented cases of gender change in individuals with CAIS (N= 156 females) or micropenis (N= 89: 79 males, 10 females). Nine (9.1%) out of 99 individuals with PAIS changed gender. Thus, self-initiated gender reassignment was rare. Gender dysphoria also appears to be a rare occurrence. The best predictor of adult gender identity in CAIS, PAIS, and micropenis is initial gender assignment.

Transactivation Properties of Wild-Type and Mutant Androgen Receptors in Transiently Transfected Primary Human Fibroblasts

BACKGROUND

Stromal cells play key roles during androgen-mediated male sexual differentiation. Our objective was to establish a transient transfection method for primary human fibroblasts enabling functional characterization of wild-type (wt) and mutant androgen receptor (AR) plasmid constructs, corresponding to partial and complete androgen insensitivity syndrome (PAIS/CAIS).

METHODS

An AR-negative fibroblast strain (ARD842) was established from the gonads of a CAIS patient. Wt-AR or either mutants L712F (PAIS), R774C or V866M (CAIS) were transfected using a polyamine-based procedure. Alternatively, two AR-positive male foreskin fibroblast strains were investigated. Androgen-induced activation of two co-transfected reporter plasmids ((ARE)(2)TATA-, MMTV-luciferase) was measured.

RESULTS

All three fibroblast strains showed a ligand-dependent rise of luciferase activity after transfection of wt-AR. Mutant plasmids were assessed in AR-negative ARD842 cells. While L712F showed high partial activity, R774C and V866M were nearly inactive. The intrinsic AR of normal foreskin fibroblasts revealed no measurable ligand-inducible reporter gene activity.

CONCLUSIONS

Polyamine-based transfection of AR plasmids into cultured fibroblasts provides a promising tool for analysis of AR transactivation, thereby considering a stromal cellular background. This is supported by the mutant ARs which showed the expected levels of impaired transactivation with respect to the corresponding AIS phenotypes. The role of the intrinsic AR in normal male human foreskin fibroblasts needs further exploration.