Androgen Insensitivity Syndrome DUE to Non-Coding Variation in the Androgen Receptor Gene: Review of the Literature and Case Report of a Patient with Mosaic c.-547C>T Variant

Sexual development (SD) is a complex process with strict spatiotemporal regulation of gene expression. Despite advancements in molecular diagnostics, disorders of sexual development (DSD) have a diagnostic rate of ~50%. Androgen insensitivity syndrome (AIS) represents the most common form of 46,XY DSD, with a spectrum of defects in androgen action. Considering the importance of very strict regulation of the SD, it is reasonable to assume that the genetic cause for proportion of the DSD lies in the non-coding part of the genome that regulates proper gene functioning. Here we present a patient with partial AIS (PAIS) due to a mosaic de novo c.-547C>T pathogenic variant in the 5'UTR of androgen receptor (AR) gene. The same mutation was previously described as inherited, in two unrelated patients with complete AIS (CAIS). Thus, our case further confirms the previous findings that variable gene expressivity could be attributed to mosaicism. Mutations in 5'UTR could create new upstream open reading frames (uORFs) or could disrupt the existing one. A recent systematic genome-wide study identified AR as a member of a subset of genes where modifications of uORFs represents an important disease mechanism. Only a small number of studies are reporting non-coding mutations in the AR gene and our case emphasizes the importance of molecular testing of the entire AR locus in AIS patients. The introduction of new methods for comprehensive molecular testing in routine genetic diagnosis, accompanied with new tools for in sillico analysis could improve the genetic diagnosis of AIS, and DSD in general.

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.

Vaginal Reconstruction in Patients with vaginal agenesis: Options and Outcome: A single-center experience

Objectives

To assess the postoperative functional, anatomical outcome and complications of various surgical procedures of vaginoplasty performed for patients with vaginal agenesis at our institution.

Methods

This was a cross-sectional study of 14 patients (age range 17-40 years), who underwent vaginoplasty at the Aga Khan University Hospital, Karachi, Pakistan between January 2008 to December 2018. We aimed to assess the anatomical outcomes in terms of vaginal depth, axis and functional outcome as painless and satisfactory vaginal intercourse.

Results

The mean age and mean body mass index (BMI) of the cases were 26.8 ± 8.1 years and 27.7143 ± 4.6 respectively. All were phenotypically female, with only two cases of XY genotype. Two patients were married on presentation. On evaluation, four cases had Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome, three had androgen insensitivity syndrome (AIS), one case had congenital adrenal hyperplasia and six cases did not fit into any diagnosis. Associated renal anomalies were diagnosed in 14.3% of cases. The performed procedures were; Singaporean flap vaginoplasty (in four patients), Lee's, modified McIndoe and pull-through vaginoplasty (in three each patients), and Davydov vaginoplasty (in one patient). One patient was complicated by intraoperative bladder injury (p<0.63) and two cases by vaginal stenosis (p<0.43). The mean operative time was 120 minutes and the mean estimated blood loss was 200mls. Postoperatively, the vaginal length varied from 6-10 cm with a normal vaginal axis and satisfactory sexual activity.

Conclusions

Vaginal agenesis is associated with several sexual disorders and despite the various surgical options available, the best procedure in terms of fewer complications and best surgical outcome is yet to be determined.

Clinical characteristics, AR gene variants, and functional domains in 64 patients with androgen insensitivity syndrome

BACKGROUND

Androgen insensitivity syndrome (AIS) is caused by abnormal androgen receptor (AR) genes that show variable genotypes and phenotypes. However, the correlation between genotype and phenotype is unclear.

METHODS

We retrospectively evaluated 64 patients with AIS at Shanghai Children's Hospital from 2015 to 2022. We analysed the clinical data of the patients, including hormone levels, AR gene variants, and functional domains.

RESULTS

Variants occurred in the 3 major functional domains in 56 patients, including 23 patients with complete androgen insensitivity syndrome (CAIS) and 33 with partial androgen insensitivity syndrome (PAIS). The incidence of nonscrotal fusion (P = 0.019) and proximal urethral opening (P = 0.0002) in the ligand-binding domain (LBD) group was higher than that in the non-LBD group. The phallus length in the LBD group was significantly shorter than that in the non-LBD group (P = 0.009). The external masculinization score (EMS) in the LBD group was significantly lower than that in the non-LBD group (P = 0.013). The levels of inhibin-B (INHB; P = 0.0007), basal luteinizing hormone (LH; P = 0.033), LH peak (P = 0.002), and testosterone (T) after human chorionic gonadotropin (HCG) stimulation (P = 0.001) in the LBD group were higher than those in the non-LBD group. There were 53 variants in 64 patients, including 42 reported and 11 novel AR variants, including p.Met247Arg, p.Asp266Glyfs*39, p.Arg362Serfs*140, p.Ala385Val, p.Glu541Asp, p.Pro613Leu, p.Pro695Leu, p.Asn757Asp, c.1616 + 1dup, c.1886-1G > A and exon 5-7 deletion.

CONCLUSIONS

The EMS of patients with AIS in the LBD group was significantly lower than that in the non-LBD group. The phallus length was shorter, and the incidences of proximal urethral opening and nonscrotal fusion were higher, suggesting that the phenotypes in the LBD group were more severe. The levels of INHB, basal LH, peak LH, and T after HCG stimulation in the LBD group were higher than those in the non-LBD group, suggesting that androgen resistance in the LBD group was more severe. We identified 53 variants in 64 patients: 42 reported and 11 novel AR variants. These findings provide new and deeper insight into AIS diagnosis and genetic assessment of AIS.

Clinical, hormonal and genetic characteristics of androgen insensitivity syndrome in 39 Chinese patients

BACKGROUND

Abnormal androgen receptor (AR) genes can cause androgen insensitivity syndrome (AIS), and AIS can be classified into complete androgen insensitivity syndrome (CAIS), partial androgen insensitivity syndrome (PAIS) and mild AIS. We investigated the characteristics of clinical manifestations, serum sex hormone levels and AR gene mutations of 39 AIS patients, which provided deeper insight into this disease.

METHODS

We prospectively evaluated 39 patients with 46, XY disorders of sex development (46, XY DSD) who were diagnosed with AIS at the Department of Endocrinology of Shanghai Children's Hospital from 2014 to 2019. We analysed clinical data from the patients including hormone levels and AR gene sequences. Furthermore, we screened the AR gene sequences of the 39 AIS patients to identify probable mutations.

RESULTS

The 39 AIS patients came from 37 different families; 19 of the patients presented CAIS, and 20 of them presented PAIS. The CAIS patients exhibited a higher cryptorchidism rate than the PAIS (100 and 55%, P = 0.001). There were no significant difference between the CAIS and PAIS groups regarding the levels of inhibin B (INHB), sex hormone-binding globulin (SHBG), basal luteinizing hormone (LH), testosterone (T), or basal dihydrotestosterone (DHT), the T:DHT ratio, DHT levels after human chorionic gonadotropin (HCG) stimulation or T levels after HCG stimulation. However, the hormone levels of AMH (P = 0.010), peak LH (P = 0.033), basal FSH (P = 0.009) and peak FSH (P = 0.033) showed significant differences between the CAIS group and the PAIS group. Twenty-one reported pathogenic and 9 novel AR mutations were identified. Spontaneous AR mutations were found in 5 AIS patients, and 21 patients inherited mutations from their mothers, who carried heterozygous mutations.

CONCLUSIONS

Forty-six XY DSD patients with cryptorchidism and female phenotypes were highly suspected of having AIS. We demonstrated that CAIS patients could not be distinguished by their hormone levels alone. Compared with PAIS patients, CAIS patients exhibited higher basal FSH, peak FSH, and peak LH hormone levels but lower AMH expression. We identified 21 reported pathogenic AR mutations and 9 novel AR mutations that led to different types of AIS. Missense mutations were the major cause of AIS and mostly occurred in exon 7 of the AR gene. These findings provided deeper insight into the diagnosis and classification of AIS and will even contributed to its clinical assessment.

Testicular Feminization or Androgen Insensitivity Syndrome (AIS) in Iran: a Retrospective Analysis of 30-Year Data

BACKGROUND

Androgen insensitivity syndrome (AIS) or testicular feminization is a partial or complete inability of cell response to androgen. The cause is enzymatic defect in synthesis of testosterone, resulting sexually immature phenotypically female, with primary amenorrhea. There are three categories of AIS, complete, partial and mild, depending on the degree of external genital masculinization. The aim of this study was to find out chromosomal abnormalities, and correlation between AIS and maternal/paternal age, parents' consanguineous marriage, family history and clinical observation, in Iranian AIS patients.

METHOD

This study includes a retrospective data analysis of 72,000 families' medical records in the Genetic Clinic in Tehran, during a 30-yr period (1984-2014). The essential basis for the patients' referral to the clinic by gynecologists was primary amenorrhea. Cytogenetic abnormalities has been confirmed by chromosome G-banding and conventional staining methods.

RESULTS

Seventy AIS female patients with 46XY pattern were cytogenetically diagnosed and the frequency of AIS syndrome was estimated about 0.05% (∼70/140000). The results showed no association between AIS and maternal or paternal age nor were the marital pattern of the parents. The clinical findings illustrated that primary amenorrhea had the highest indication for referral of AIS patients for genetic counseling and cytogenetic study.

CONCLUSION

No correlation was observed between AIS and maternal or paternal age or consanguineous marriages. Amenorrhea is the most clinically observed sign of AIS patients.