Androgen Receptor Gene Mutations Research Articles

Abstract LB177: Discovery of HC-4955, a novel AR-V7-targeting PROTAC for the treatment of mCRPC

Abstract Prostate cancer is the second most commonly diagnosed cancer and the second leading cause of cancer death among men worldwide. Androgens play an important role in the development and progression of prostate cancers and targeting androgen receptor (AR) signaling axis over decades has remained a mainstay of prostate cancer therapy. Next generation hormonal agents (NHAs) enzalutamide and abiraterone have brought clinical benefits for metastatic castrate-resistant prostate cancer (mCRPC) patients, AR axis-targeted therapy resistance is inevitable due to AR gene amplification or mutations. AR-V7 is the most clinically relevant AR splice variant associated with endocrine resistance and poor prognosis. AR-V7 constitutively activates AR signaling and lacks the ligand binding domain (LBD) where hormones and AR antagonists interact, resulting in resistance to AR signaling inhibitors (ARSi). Thus, AR-V7 is a promising therapeutic target to address ARSi resistance in mCRPC. We have discovered a highly potent AR-V7 proteolysis targeting chimera (PROTAC), HC-4955 that degrades both the wild-type AR (WT-AR) and AR-V7 mutant. HC-4955 degrades AR-V7 with DC50 < 5 nM. In silico molecular docking analysis predicts the binding of HC-4955 to the N-terminal domain of AR and then the essential amino acids contributed to HC-4955 binding are validated by mutational analysis studies. HC-4955 also potently degrades mutants of AR-LBD mutations including L702H and T878A and these mutations are also associated with ARSi resistance. HC-4955 strongly inhibits proliferation of ARSi-resistant prostate cancer cell lines with IC50 < 10 nM. HC-4955 shows a robust anti-tumor activity in the AR-V7-bearing 22Rv1 cell line derived tumor xenograft (CDX) and patient-derived xenograft (PDX) mouse models, with majority of the tumors completely regressed and > 90% AR-V7 expression decreased at 1-5 mg/kg (QD, PO) in these models. The pre-clinical results support the clinical development of HC-4955 for the treatment of mCRPC. Selected pre-clinical data along with the chemical structure of HC-4955 will be presented. Citation Format: Jing Li, Zhilin Tu, Wu Du, Xi Xiang, Zeyu Wen, Yang You, Lijuan Zhao, Yin Chen, Chengcheng Yang, Hongwei Yuan, Xinghai Li. Discovery of HC-4955, a novel AR-V7-targeting PROTAC for the treatment of mCRPC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB177.

SiRNA-based approaches for castration-resistant prostate cancer therapy targeting the androgen receptor signaling pathway.

Androgen deprivation therapy is a common treatment method for metastatic prostate cancer through lowering androgen levels; however, this therapy frequently leads to the development of castration-resistant prostate cancer (CRPC). This is attributed to the activation of the androgen receptor (AR) signaling pathway. Current treatments targeting AR are often ineffective mostly due to AR gene overexpression and mutations, as well as the presence of splice variants that accelerate CRPC progression. Thus there is a critical need for more specific medication to treat CRPC. Small interfering RNAs have shown great potential as a targeted therapy. This review discusses prostate cancer progression and the role of AR signaling in CRPC, and proposes siRNA-based targeted therapy as a promising strategy for CRPC.

Molecular genetics and general management of androgen insensitivity syndrome.

Androgen insensitivity syndrome (AIS) is a rare genetic disorder that affects the development of the male reproductive system in individuals with a 46,XY karyotype. In addition to physical impacts, patients with AIS may face psychological distress and social challenges related to gender identity and acceptance. The major molecular etiology of AIS results from hormone resistance caused by mutations in the X-linked androgen receptor (AR) gene. Depending on the severity of androgen resistance, the wide spectrum of AIS can be divided into complete AIS (CAIS), partial AIS (PAIS), or mild AIS (MAIS). Open issues in the treatment and management of AIS include decisions about reconstructive surgery, genetic counseling, gender assignment, timing of gonadectomy, fertility and physiological outcomes. Although new genomic approaches have improved understanding of the molecular causes of AIS, identification of individuals with AIS can be challenging, and molecular genetic diagnosis is often not achievable. The relationship between AIS genotype and phenotype is not well established. Therefore, the optimal management remains uncertain. The objective of this review is to outline the recent progress and promote understanding of AIS related to the clinical manifestation, molecular genetics and expert multidisciplinary approach, with an emphasis on genetic etiology.

Postponed gonadectomy until adulthood for a patient with a novel mutation in androgen receptor gene: a case report

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

A prime editor efficiently repaired human induced pluripotent stem cells with AR gene mutation (c.2710G > A; p. V904M)

Prime Editor (PE) is a precise genome manipulation technology based on the CRISPR-Cas9 system, while its application in human induced pluripotent stem cells (iPSCs) remains limited. Here, we established a repaired hiPS cell line (SKLRMi001-A-1) from hiPSCs with androgen receptor (AR) mutation (c.2710G > A; p.V904M). The repaired iPSC line expressed pluripotency markers, retained normal karyotype, showed the capability of differentiating into three germ layers and was absence of mycoplasma infection. The repaired iPSC line will help to elucidate the mechanism of androgen insensitivity syndrome (AIS) and benefit treatment for AIS in the future.

Mild Androgen Insensitivity Syndrome presenting in male with infertility and sexual difficulties

Androgen insensitivity syndrome has a wide spectrum of presentations. It results from a mutation in androgen receptor (AR) gene. It ranges from mild androgen insensitivity syndrome (MAIS) which is the mildest form to complete androgen insensitivity syndrome (CAIS). In case of MAIS, the abnormality that can be observed appears to be male infertility and sexual difficulties including premature ejaculation and erectile dysfunction. In this case report, we discuss a case of MAIS in a 37-year-old male who presented with infertility, premature ejaculation, and secondary erectile dysfunction. Bangladesh Journal of Medical Science Vol. 22 No. 02 April’23 Page : 442-444

Association of Androgen-Receptor Gene Mutations with the Copy Number of Androgen-Receptor Silk Protein A Complex and Glutathione-S-Transferases T1 and M1 in Prostate Cancer Patients.

The purpose of our work was to explore the association of mutations in the androgen receptor gene and copy numbers of the androgen-receptor silk protein A complex with glutathione-S-transferases T1 and M1 in prostate cancer patients. Eighty-five patients with PC and 85 healthy controls were included in the study. Fasting peripheral venous blood was collected, whole blood genomic DNA was extracted, and AR gene-receptor genotype was detected by a high-resolution melting curve analysis detection technology. Expression levels of androgen receptor (AR) and filamin protein A (FlnA) were detected by Western blotting. RT-PCR was used to detect the copy number of T1 and M1 glutathione-S-transferases. The wild-type androgen receptor gene rs5918762 is of TT type. The frequencies of CC and TC genes in the prostate cancer group were significantly higher than those in the normal control group (P < 0.05). Compared with TT-type PC patients, PC patients with TC-type and CC-type had higher expression levels of sex hormone receptor silk protein A complex and higher copy numbers of GSTT1 and GSTM1 (P < 0.05). Androgen-receptor gene mutation (T ⟶ C) was significantly positively correlated with the expression level of androgen-receptor silk protein A complex and the copy number of GSTT1 and GSTM1. Androgen-receptor gene polymorphisms were significantly associated with expression levels of androgen receptor complex A and silk proteins, and copy numbers of T1 and M1 glutathione-S-transferases. A combination of four factors can be used to identify prostate cancer susceptibility and disease progression.

Abstract A037: PROTACs as emergent treatment modality of metastatic prostate cancer. [R

Abstract Prostate cancer is one of the most commonly diagnosed and fourth leading cause of cancer death in men, with low survival rates for metastatic cancers. Androgen receptor (AR) is one of the most altered Oncogenes in castration-resistant prostate cancer (mCRPC). Suppression of AR signalling is one of the common strategies to treat prostate cancer. Androgen deprivation therapy (ADT) has been the backbone therapy for decades and demonstrated survival benefit when used alongside other therapies including Docetaxel, cabazitaxel or hormone based anti-androgen therapies such as Enzalutamide, abiraterone, darolutamide, and apalutamide. Unfortunately, amplification or mutation in AR gene along with its associated pathway such as alteration of PI3K pathway or upregulation of MYC oncogene drive mCRPC cell proliferation and confers resistance to existing therapies. To overcome such resistance mechanisms, targeted therapy towards Androgen receptor has emerged, where ligand conjugated small molecule inhibitors using proteolysis targeting chimera (PROTAC) strategy, could effectively downregulate the AR expression. Several PROTACs as ‘Androgen Receptor Degraders (ARD)’ are showing promising activity in early-stage clinical studies. Although a promising strategy, challenges exist for its development in future; given that finding the most appropriate protein-protein interaction is essential to find optimal ligand to successfully design PROTAC. Similarly, challenges to optimize safety and efficacy of PROTACs in the clinic, also remain to be addressed. Here we aim to provide comprehensive review, including patent landscape of the therapeutic benefits of using PROTACs and its future development prospect in context to metastatic prostate cancer. Citation Format: Prashant Kashinath Bhavar, Uday Kumar Surampudi, Partha Pratim Sarma, Satish Katike, Adilakshmi Gandham. PROTACs as emergent treatment modality of metastatic prostate cancer. [R [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A037.

Characterization of a novel androgen receptor gene variant identified in an Iranian family with complete androgen insensitivity syndrome (CAIS): a molecular dynamics simulation study

Androgen insensitivity syndrome (AIS) is a common form of 46, XY disorder in sex development disease (DSD). It is due to the androgen receptor (AR) gene mutations and includes clinical subgroups of complete AIS (CAIS) and partial AIS (PAIS), along with a vast area of clinical heterogeneity of completely normal female external genitalia to male infertility. In this study, the Whole Exome Sequencing (WES) was utilized to detect the cause of DSD in a consanguineous Iranian family with two female patients with normal external genitalia and 46, XY karyotype. Sanger sequencing was applied to validate the candidate variant. Next, we predicted the structural alteration induced by the variant on AR protein using bioinformatics analysis such as molecular dynamic (MD) and molecular docking simulations. WES results identified a novel hemizygous p.L763V variant in the AR gene in the proband that was compatible with the X-linked recessive pattern of inheritance. Bioinformatics studies confirmed the loss of AR function. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, it was categorized as pathogenic. This study broadens the AR mutation spectrum and introduces the novel p.L763V missense pathogenic variant leading to AR failure to bind to its ligand, and the resulting CAIS clinical subgroup. This study presents a prosperous application of WES and bioinformatics analysis to recognize the underlying cause of DSD in Iran, necessary for its clinical/psychological management. Communicated by Ramaswamy H. Sarma

Developing New Treatment Options for Castration-Resistant Prostate Cancer and Recurrent Disease.

Prostate cancer (PCa) is a major diagnosed cancer among men globally, and about 20% of patients develop metastatic prostate cancer (mPCa) in the initial diagnosis. PCa is a typical androgen-dependent disease; thus, hormonal therapy is commonly used as a standard care for mPCa by inhibiting androgen receptor (AR) activities, or androgen metabolism. Inevitably, almost all PCa will acquire resistance and become castration-resistant PCa (CRPC) that is associated with AR gene mutations or amplification, the presence of AR variants, loss of AR expression toward neuroendocrine phenotype, or other hormonal receptors. Treating CRPC poses a great challenge to clinicians. Research efforts in the last decade have come up with several new anti-androgen agents to prolong overall survival of CRPC patients. In addition, many potential targeting agents have been at the stage of being able to translate many preclinical discoveries into clinical practices. At this juncture, it is important to highlight the emerging strategies including small-molecule inhibitors to AR variants, DNA repair enzymes, cell survival pathway, neuroendocrine differentiation pathway, radiotherapy, CRPC-specific theranostics and immune therapy that are underway or have recently been completed.

Advances in the Current Understanding of the Mechanisms Governing the Acquisition of Castration-Resistant Prostate Cancer.

Simple SummaryCastration-resistant prostate cancer (CRPC) is an advanced form of prostate cancer with a low survival rate, as the CRPC patients only survive for 9–13 months on average. In this narrative review, we first outline the most common androgen receptor (AR) receptor-related mechanisms, highlighting the important role of ARs in the development of CRPC. We also discuss the key importance of non-coding RNAs (ncRNAs) in this setting, including long ncRNAs and microRNAs. Overall, studies of the molecular biological mechanisms governing the CRPC will facilitate the development of appropriate targeted therapeutics, improving treatment options for the CRPC patients.Despite aggressive treatment and androgen-deprivation therapy, most prostate cancer patients ultimately develop castration-resistant prostate cancer (CRPC), which is associated with high mortality rates. However, the mechanisms governing the development of CRPC are poorly understood, and androgen receptor (AR) signaling has been shown to be important in CRPC through AR gene mutations, gene overexpression, co-regulatory factors, AR shear variants, and androgen resynthesis. A growing number of non-AR pathways have also been shown to influence the CRPC progression, including the Wnt and Hh pathways. Moreover, non-coding RNAs have been identified as important regulators of the CRPC pathogenesis. The present review provides an overview of the relevant literature pertaining to the mechanisms governing the molecular acquisition of castration resistance in prostate cancer, providing a foundation for future, targeted therapeutic efforts.

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

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. To determine the AR gene mutations associated with male DSD in four unrelated Vietnamese patients. 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. Four distinct novel mutations, namely c.1834T > A (p.Cys612Ser), c.2122C > G (p.Leu708Val), c.2630T > G (p.Phe877Cys), and c.2641C > 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. 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.

Anti-Androgen Receptor Therapies in Prostate Cancer: A Brief Update and Perspective.

Prostate cancer is a major health issue in western countries and is the second leading cause of cancer death in American men. Prostate cancer depends on the androgen receptor (AR), a transcriptional factor critical for prostate cancer growth and progression. Castration by surgery or medical treatment reduces androgen levels, resulting in prostatic atrophy and prostate cancer regression. Thus, metastatic prostate cancers are initially managed with androgen deprivation therapy. Unfortunately, prostate cancers rapidly relapse after castration therapy and progress to a disease stage called castration-resistant prostate cancer (CRPC). Currently, clinical treatment for CRPCs is focused on suppressing AR activity with antagonists like Enzalutamide or by reducing androgen production with Abiraterone. In clinical practice, these treatments fail to yield a curative benefit in CRPC patients in part due to AR gene mutations or splicing variations, resulting in AR reactivation. It is conceivable that eliminating the AR protein in prostate cancer cells is a promising solution to provide a potential curative outcome. Multiple strategies have emerged, and several potent agents that reduce AR protein levels were reported to eliminate xenograft tumor growth in preclinical models via distinct mechanisms, including proteasome-mediated degradation, heat-shock protein inhibition, AR splicing suppression, blockage of AR nuclear localization, AR N-terminal suppression. A few small chemical compounds are undergoing clinical trials combined with existing AR antagonists. AR protein elimination by enhanced protein or mRNA degradation is a realistic solution for avoiding AR reactivation during androgen deprivation therapy in prostate cancers.

Yolk Sac Tumor in an Infant with Androgen Insensitivity Syndrome: A Case Report and Review of the Literature

Background: Androgen insensitivity syndrome (AIS) is a disorder of sexual differentiation caused by complete or partial resistance to the biological action of androgens. The common malignant tumors associated with this syndrome are seminomas. However, the risk of malignancy in childhood remains low. Case Report: A 8-month-old child with a female phenotype and a 46, XY karyotype, presented with bilateral inguinal hernia. The patient underwent right radical inguinal orchiectomy with high ligation of the spermatic cord and laparoscopic percutaneous extra-peritoneal herniorrhaphy. Final pathology confirmed a pure yolk sac tumor (YST) from the right testis. Androgen receptor (AR) gene mutation was found in the children. The follow-up ultrasonography shown no recurrence, with serum AFP returned to normal within 3 months. Conclusion: The case we presented is relatively infrequent in the literature with yolk sac tumor in a AIS children presented with a palpable lump inguinal region.

Evaluation of basal hormone levels and androgen receptor gene mutations in individuals with recurrent abortion.

A recurrent miscarriage is at least two consecutive miscarriages in the first trimester of pregnancy. Due to the dependence of pregnancy on endocrine changes in the menstrual cycle, its disorders can also affect the outcome of pregnancy. In addition to hormonal disorders, genetic changes are essential factors in recurrent miscarriage. The development and maturation of ovulation depend on the molecular signaling pathways that respond to androgens. Hundreds of mutations leading to resistance to androgen receptor (AR) gene function have been recorded, including the 5'UTR polymorphic region. Therefore, considering the role of androgen receptors and hormonal changes in recurrent miscarriage, this study was performed to investigate the relationship between hormonal changes and AR gene mutations in patients with recurrent miscarriage. In this regard, a case-control study was performed on 150 patients with miscarriage referred to the infertility center. Hysterosalpingography, parental karyotype, vaginal ultrasound, antiphospholipid antibody measurement, anticardiolipin antibody, history and physical examination were performed to evaluate the possible causes of recurrent miscarriage. Hormone levels of LH, FSH, TSH, and Prolactin were measured and compared in two groups with known and unknown causes. Blood samples were also taken from patients, and after DNA extraction, the PCR method was used to determine AR gene mutations. The mean age was 30.2 ± 7.1 years, the mean number of abortions was 2.6 ± 1.2, and the mean duration of marriage was 6.1 ± 2.1 years. The mean of hormones in the two groups with known and unknown causes was compared, that TSH was significantly lower in the group with unknown cause (P = 0.031) and prolactin was higher in recurrent miscarriage patients with polycystic ovaries (P = 0.048). Regarding genetic evaluation, in the 5'UTR region of the androgen receptor gene, deletion of T nucleotide was observed in the +25 position, but no significant difference was found between the two groups. Generally, the findings of this study showed that thyroid dysfunction and hyperprolactinemia should be considered as an endocrine disorder in people with recurrent miscarriage, and genetic evaluation showed that the AR gene mutation was not associated with recurrent miscarriage.

The FKBP4 gene, encoding a regulator of the androgen receptor signaling pathway, is a novel candidate gene for androgen insensitivity syndrome

Androgen insensitivity syndrome (AIS), manifesting incomplete virilization in 46,XY individuals, is caused mostly by androgen receptor (AR) gene mutations. Therefore, a search for AR mutations is a routine approach in AIS diagnosis. However, some AIS patients lack AR mutations, which complicates the diagnosis. Here, we describe a patient suffering from partial androgen insensitivity syndrome (PAIS) and lacking AR mutations. The whole exome sequencing of the patient and his family members identified a heterozygous FKBP4 gene mutation, c.956T>C (p.Leu319Pro), inherited from the mother. The gene encodes FKBP prolyl isomerase 4, a positive regulator of the AR signaling pathway. This is the first report describing a FKBP4 gene mutation in association with a human disorder of sexual development (DSD). Importantly, the dysfunction of a homologous gene was previously reported in mice, resulting in a phenotype corresponding to PAIS. Moreover, the Leu319Pro amino acid substitution occurred in a highly conserved position of the FKBP4 region, responsible for interaction with other proteins that are crucial for the AR functional heterocomplex formation and therefore the substitution is predicted to cause the disease. We proposed the FKBP4 gene as a candidate AIS gene and suggest screening that gene for the molecular diagnosis of AIS patients lacking AR gene mutations.

A Novel Mutation of the AR Androgen Receptor Gene

Abstract Androgen insensitivity syndrome (AIS), formerly known as testicular feminization, is an X-linked recessive condition resulting in a failure of normal masculinization of the external genitalia in chromosomally male individuals. The basic etiology of androgen insensitivity syndrome is a loss-of-function mutation in the androgen receptor (AR) gene. Loss of AR function means that, despite normal levels of androgen synthesis, the typical postreceptor events that mediate the effects of hormones on tissues do not occur. This results in the phenotype of prenatal undervirilization of external genitalia, absence of pubic and axillary hair, lack of acne, and absence of voice changes at puberty We present This baby reffered at age of 2 months from pediatric surgery as a case of bilateral inguinal hernia and chromosomes 46xy. Phenotypically female no male structures no phallus and single opening and visible labia, both test are in the inguinal canals. HCG stimulation test shows: Testosterone: the level at (0) time: 0.8 nmol/l then 3 days: 31.4 nmol/l. DHT dihydrotetostrerone: the level at (0) time: 13 NG/L then 3 days: 485 The baby was given 3 doses of Testosterone injections 150mg but no response at the genetalia. Radiological investigations shows ultrasound both tests at the inguinal canals and no uterus Also MRI of pelvis shows absence of uterus and both test at the inguinal canals Molecular genetics analysis for Androgen receptor gene: Exon 7 c.2512 G &amp;gt;A hem. P.Glu838lys missense, novel VUS,likely pathogenic. The segregations analysis test in the process. Her we present a novel mutation of the AR gene not reported yet in literature.

Unexpected Diagnosis of Complete Androgen Insensitivity Syndrome (CAIS) During Inguinal Hernia Repair in 11-year-old-girl

Complete Androgen Insensitivity Syndrome (CAIS) is an X-link recessive genetic mutation of androgen receptor (AR) gene leading to complete inability of cell to respond to the androgens. CAIS occurs in 1 out of 20,400 XY live-birth babies, and affects about 1–2% of prepubertal girls that present with an inguinal hernia. Although individuals with CAIS have XY, those with grades 6 and 7 on the Quigley scale are born phenotypically female, without any signs of genital masculinization. Thus, individuals affected by CAIS develop a normal external female phenotype with normal female external genitalia, well-developed breast, absent uterus, and bilateral undescended testicles. The question of CAIS diagnosis does not come forward until the absent menses at the puberty is noted or accidentally during an inguinal hernia repair in a premenarchal girl. The present study reports a case of inguinal hernia repair on 11-year-old girl, which led to unexpected intraoperative notion of CAIS. The diagnostic work-up, genetic counseling, sex assignment, and the need for preoperative CAIS screening in girls with bilateral inguinal hernia are described and discussed.&#x0D; Keywords: DSD, CAIS, bilateral inguinal hernia, gonadectomy

Clinical characteristics and molecular genetics of complete androgen insensitivity syndrome patients: a series study of 30 cases from a Chinese tertiary medical center

To study the clinical characteristics and genetic basis of complete androgen insensitivity syndrome (CAIS) in patients from the People's Republic of China. CAIS patients with 46 XY karyotype produce male levels of androgens but present with female external genitalia and secondary sex characteristics. The majority of affected individuals have androgen receptor (AR) gene mutations. This case series explored clinical and molecular characteristics of CAIS patients from the People's Republic of China. Genomic DNA from peripheral blood of clinically diagnosed CAIS patients was sequenced for mutation in the androgen receptor (AR) gene and steroid 5α-reductase type 2 gene (SRD5A2). Participants were recruited from Peking Union Medical College Hospital when they came in for consultation. Thirty patients from unrelated families were recruited. Data from medical documents recording diagnosis and treatment of these patients were retrospectively collected. Patient genotypes were determined by sequencing the AR and SRD5A2 genes. Their clinical characteristics were summarized based on symptoms, hormone profiles, operative findings, and pathological results. Twenty-one patients diagnosed with CAIS had mutations in AR exons. Analysis of AR exons revealed the presence of seven novel mutations (c.58C>T, c.645_652delGGGGGCTC, c.910G>T, c.1078C>T, c.1786T>A, c.2230G>T, and c.2522G>C); of these mutations, 47.6% (10/21) were located in the ligand-binding domain. Gonadal insufficiency was found in one case of CAIS. Among the remaining nine patients, three had SRD5A2 mutations and therefore a steroid 5α-reductase deficiency. No AR or SRD5A2 mutations were detected in the other six patients. This study broadens the spectrum of known AR gene mutations responsible for CAIS, and implies that there can be more complex underlying causes of CAIS.

In vitro functional characterization of androgen receptor gene mutations at arginine p.856 of the ligand-binding-domain associated with androgen insensitivity syndrome

Androgens are critical for male sex differentiation. Their actions are mediated by the androgen receptor (AR). Mutations disrupting AR function result in the androgen insensitivity syndrome (AIS). In this study, we identified in a patient with complete AIS, a novel AR mutation p.R856L. To investigate the functional properties of p.R856L, we performed functional studies. In comparison, we have characterized two already described mutations: p.R856H and p.R856C. We used a model composed of two different promoters fused to a reporter gene, two cell lines, and showed that all mutations were able to transactivate the (ARE)2-TATA promoter expressed in CHO cells more highly. Moreover, we confirmed the pathogenicity of the p.R856L and p.R856C mutations, and their associations with complete AIS. In contrast, the p.R856H mutation, which is associated with a spectrum of AIS phenotypes, showed less severe transcriptional constraints. Altogether, our studies allowed us to better characterize arginine residue at p.R856 position.