Mild Androgen Insensitivity Syndrome Research Articles

THU209 Small INDELs In The Androgen Receptor Gene: Phenotype Implications And Mechanisms Of Mutagenesis In Androgen Insensitivity Syndrome

Abstract Disclosure: R.L. Batista: None. R.M. Ramos: None. A.F. Afonso: None. R.J. Petroli: None. M.Y. Nishi: None. M.M. Ferrari: None. S. Domenice: None. B.B. Mendonca: None. Small indels are insertions or deletions of one or more nucleotides into the DNA sequence. Indels are highly abundant in human genomes and have contributed massively to genome evolution. However, the role of indels and their underlined mechanisms of mutagenesis in Mendelian disorders still needs to be appreciated. To explore the contribution of indels in a monogenic disorder, we analyzed all indels in the androgen receptor gene, including three novel indels, using Androgen Insensitivity Syndrome (AIS) as a model. The goal was to profile indels in AIS. To build this profile, we analyzed the indel distribution through the AR coding region, compared with genomic and exonic populational data, and analyzed their impact on the AIS phenotype and their likely mechanism of mutagenesis. We present 82 different indels in the AR gene reported in individuals with AIS. In most cases (n=78; 95.1%), the phenotype is complete AIS (CAIS). There are four AR indels reported in mild AIS. Most short indels in the AR gene among AIS are frameshift indels (n=64; 79%). Indels are distributed along the entire AR gene, with NTD domain predominance (n=45; 54.9%), followed by LTD domain (n=28; 34.1%). Most are small deletions (n=49; 59.7%), followed by small insertions (n=29; 35.3%) and complex frameshift indels (n=4; 4.8%). Most indels are short (<10 bp; n=81 = 98.8%), with an average of 2.4 nucleotides by indel. Most indels are at non-repetitive sequences with no changes in copy counting (n = 68; 82.9%). Thirteen indels were identified within tandem repeats (15.8%), whereas seven indels were at homopolymers run (8.5%). Trinucleotide regions (Poly-Q, Poly-G) are prone to indels, but indels also happen in other trinucleotide stretches (Poli-L, Poly-P). Regarding the change in copy counting, thirty-nine (47.5%) indels are CCC indels. Indel reported in MAIS is all located at tandem repeats, while all at non-repetitive sequences caused CAIS. 3.65% of AR indels are at a 6bp consensus sequence (TG A/G A/G G/T A/C). In summary, indels represent a significant portion of the variants identified in the AR gene in patients with AIS. Unlike the non-synonymous variants related to this gene, there is a genotype-phenotype correlation (indel - CAIS congruency). However, small NFS indels at small triplet runs can slightly compromise AR function leading to the mild phenotype. Homopolymer runs, and trinucleotide repeats are exonic regions at risk for indels. Slippage explains half of the cases of AR indels. These results increase the molecular understanding of the androgen receptor disruption and the underlined mechanisms of indel mutagenesis in exonic regions and their implication on phenotype. Presentation: Thursday, June 15, 2023

Whole exome data prioritization unveils the hidden weight of Mendelian causes of male infertility. A report from the first Italian cohort.

Almost 40% of infertile men cases are classified as idiopathic when tested negative to the current diagnostic routine based on the screening of karyotype, Y chromosome microdeletions and CFTR mutations in men with azoospermia or oligozoospermia. Rare monogenic forms of infertility are not routinely evaluated. In this study we aim to investigate the unknown potential genetic causes in couples with pure male idiopathic infertility by applying variant prioritization to whole exome sequencing (WES) in a cohort of 99 idiopathic Italian patients. The ad-hoc manually curated gene library prioritizes genes already known to be associated with more common and rare syndromic and non-syndromic male infertility forms. Twelve monogenic cases (12.1%) were identified in the whole cohort of patients. Of these, three patients had variants related to mild androgen insensitivity syndrome, two in genes related to hypogonadotropic hypogonadism, and six in genes related to spermatogenic failure, while one patient is mutant in PKD1. These results suggest that NGS combined with our manually curated pipeline for variant prioritization and classification can uncover a considerable number of Mendelian causes of infertility even in a small cohort of patients.

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.

A rare case of hypergonadotrophic hypergonadism due to mild androgen insensitivity syndrome (MAIS)

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

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

Clinical and laboratory differences between chromosomal and undefined causes of non-obstructive azoospermia: A retrospective study.

Knowledge of clinical and laboratory differences between chromosomal and undefined causes aids etiological research on non-obstructive azoospermia. Compare clinical and laboratory differences between men with non-obstructive azoospermia due to chromosomal anomalies versus undefined causes. A cross-sectional retrospective study conducted at a public university hospital in Campinas (Brazil). All men aged 20-40 years with non-obstructive azoospermia were included in the analysis. The 107 cases included 14 with Klinefelter syndrome (KS) (13%), 1 with mosaic KS, 4 with sex development disorders (2 testicular XX, 1 NR5A1 gene mutation, and 1 mild androgen insensitivity syndrome) (4%), 9 with other non-obstructive azoospermia etiologies (8%), and 79 with undefined causes. The 22 chromosomal anomaly cases (14 KS, 1 mosaic KS, 2 testicular XX, 4 sex chromosome anomalies, and 1 autosomal anomaly) were compared with the 79 undefined cause cases. The KS group had lower average testicular volume, shorter penile length, and lower total testosterone levels but greater height, arm span, serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels, and gynecomastia frequency (absent in the undefined group and affecting more than half of the KS group). Patients with testicular XX DSD had LH, FSH, and penile length data intermediate between the KS and undefined cause groups, testicular volume similar to the KS group, and other data similar to the undefined group. Clinical and laboratory data differentiate men with non-obstructive azoospermia and chromosomal anomalies, particularly KS and testicular XX, from those with undefined causes or other chromosomal anomalies.

A Gly684Ala substitution in the androgen receptor is the cause for azoospermia in a Chinese family with mild androgen insensitivity syndrome and normal hormone levels.

Androgen receptor gene (AR) is essential for male growth and fertility. Its mutations are responsible for androgen insensitivity syndrome (AIS) that usually shows the phenotype of azoospermia resulting in male infertility. This study reported the first case of mild AIS with complete normal serum hormones in a Chinese family. The proband referred for infertility because of azoospermia. His uncle and two cousins are both infertile and have azoospermia. Whole-exome sequencing in the genetic analyses showed that the proband carries a novel hemizygous AR missense mutation, NM_000044.6: c.2051G>C (p.Gly684Ala), in exon four within the ligand-binding domain. His mother and maternal aunt are heterozygous carriers, while his father and brother are wildtype, indicating that the mutation in the proband was inherited from his mother. This pattern is consistent with the genetic model of the X-linked recessive inheritance of AR in AIS pathogenesis. HOPE predicts that p.Gly684Ala increases the hydrophobicity of AR but does not change the AR conformation. PolyPhen-2 predicts that p.Gly684Ala is harmful. This study provides the new knowledge to understand the AR gene mutations in MAIS.

Structural analysis of the impact of a novel androgen receptor gene mutation in two adult patients with mild androgen insensitivity syndrome

Structural analysis of the impact of a novel androgen receptor gene mutation in two adult patients with mild androgen insensitivity syndrome

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

BackgroundAbnormal 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.MethodsWe 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.ResultsThe 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.ConclusionsForty-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.

A Search for Disorders of Sex Development among Infertile Men

A retrospective cross-sectional study was performed in a DSD clinic at a tertiary service (University Hospital) to estimate the frequency of disorders of sex development (DSD) among men who seek medical care because of infertility. The sample included 84 men >20 years of age referred from 2010-2017 due to oligozoospermia or nonobstructive azoospermia of unknown etiology. Twelve cases (14%) were diagnosed as DSD, including Klinefelter Syndrome, 46,XX testicular DSD, and mild androgen insensitivity syndrome. Y chromosome microdeletions were detected in 2 patients. Among the remaining 70 cases there were patients with chromosome abnormalities which are not included in the DSD classification as well as rare NR5A1 variants of uncertain significance and hypergonadotropic hypogonadism and microorchidism in 46,XY subjects. In conclusion, the frequency of DSD in this study was 14%, consisting mainly of sex chromosome abnormalities but also 46,XX and 46,XY DSD. However, this figure may increase as further investigations are conducted in idiopathic cases with signs of primary testicular failure, which may present partial gonadal dysgenesis.

Mild androgen insensitivity syndrome: a case report

Mild androgen insensitivity syndrome: a case report

Mild androgen insensitivity syndrome presenting as male infertility with azoospermia

Androgen insensitivity syndrome results from a mutation in androgen receptor gene. It has wide spectrum of phenotypic presentations. Mild androgen insensitivity syndrome (MAIS) is the milder form, present as undervirilized male syndrome. In some instances, the only observed abnormality appears to be male infertility; therefore, MAIS could explain some cases of idiopathic male infertility. Here we describe a case of MAIS in a 38 years old male who presented with azoospermia and infertility.

A novel variant in the androgen receptor gene causing familial mild androgen insensitivity syndrome

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

Mild androgen insensitivity syndrome (MAIS): the identification of c.1783C>T mutation in two unrelated infertile men

Two unrelated men complaining of primary male infertility presented to Orient Hospital in Damascus city. Physical examination showed moderate hypoandrogenic features. Both men were azoospermic. Hormone profiles revealed an elevation...

Preserved Fertility in a Patient with Gynecomastia Associated with the p.Pro695Ser Mutation in the Androgen Receptor

The androgen insensitivity syndrome (AIS) is described as a dysfunction of the androgen receptor (AR) in 46,XY individuals, which can be associated with mutations in the AR gene or can be due to unknown mechanisms. Different mutations in AIS generally cause variable phenotypes that range from a complete hormone resistance to a mild form usually associated with male infertility. The purpose of this study was to search for mutations in the AR gene in a fertile man with gynecomastia and to evaluate the influence of the mutation on the AR transactivation ability. Sequencing of the AR gene revealed the p.Pro695Ser mutation. It is located within the AR ligand-binding domain. Bioinformatics analysis indicated a deleterious role, which was verified after testing transactivation activity and N-/C-terminal (N/C) interaction by in vitro expression of a reporter gene and 2-hybrid assays. p.Pro695Ser showed low levels of both transactivation activity and N/C interaction at low dihydrotestosterone (DHT) conditions. As the ligand concentration increased, both transactivation activity and N/C interaction also increased and reached normal levels. Therefore, this study provides functional insights for the p.Pro695Ser mutation described here for the first time in a patient with mild AIS. The expression profile of p.Pro695Ser not only correlates to the patient's phenotype, but also suggests that a high-dose DHT therapy may overcome the functional deficit of the mutant AR.

Analysis of a novel mutation of AR gene in a patient featuring mild androgen insensitivity syndrome

To investigate the clinical and molecular genetics characteristics of a patient with mild androgen insensitivity syndrome (MAIS). Clinical data of the patient was collected, and DNA was isolated from peripheral blood sample. Eight exons of AR gene were amplified by PCR with specific primers and directly sequenced by Sanger method. The results were compared with standard sequences from GenBank. Online Polyphen-2 software was applied to predict the effect of mutation on the protein function and compare the conservation of the sequence at the mutation site in various species. The exon of the AR gene containing the mutated site was analyzed in 90 unrelated normal males using PCR and restrictive digestion with Sfa NI. Sequence analysis has detected a novel missense mutation in codon 176 of exon 1 (Ser176Arg) of the AR gene. Analysis with polyphen-2 software has indicated the codon to be highly conserved across various species, and that the S176A mutation has caused damage to the protein structure and function (prediction score=0.999). The same mutation was not detected in 90 healthy males. The S176A mutation of the AR gene may contribute to the mild androgen insensitivity syndrome.

A novel mutation (c.T3816 > C) in the androgen receptor gene in a 46,XY female patient with androgen insensitivity syndrome

Androgen receptor (AR) gene mutations are the most frequent cause of 46,XY disorders of sex development (DSD), and are associated with a variety of phenotypes ranging from phenotypic women (Complete Androgen Insensitivity Syndrome or CAIS) to milder degrees of undervirilisation (Partial Androgen Insensitivity Syndrome or PAIS) or men with infertility only (Mild Androgen Insensitivity Syndrome or MAIS). In this paper, we present the results of clinical, endocrine and molecular trials in a patient hospitalised because of primary amenorrhoea with typical phenotype of CAIS. The main objective of this study was to determine the molecular cause of androgen insensitivity syndrome in a 46,XY female patient. Molecular analysis of the AR gene was conducted using MSSCP (Multitemperature Single Strand Conformation Polymorphism) and sequencing methods. MSSCP analysis showed changes in electrophoretic mobility in exon 8 of the AR gene. Sequencing analysis revealed a missense mutation which has not been previously described. This is a c.T3816 > C transition mutation which causes a S901P substitution in the amino acid chain (based on the latest NCBI reference sequence NM 000044.2). The identified c.T3816 > C mutation in AR gene provides further evidence for the correlation between specific AR mutations and phenotype corresponding to androgen insensitivity.

Androgen Insensitivity Syndrome

The androgen insensitivity syndromes (AIS) fall within the generic category of 46,XY DSD (disorder of sex development) and present as phenotypes associated with complete or partial resistance to the action of androgens. Three categories are recognized: complete androgen insensitivity syndrome (CAIS), partial androgen insensitivity syndrome (PAIS), mild androgen insensitivity syndrome (MAIS). The androgen receptor (AR) is encoded by an 8 exon gene on the X chromosome long arm. More than 800 mutations in the AR gene have been reported in AIS patients (www.androgendb.mcgill.ca/). They are distributed throughout the gene with a preponderance located in the ligand binding domain. The most severe mutations are generally associated with a CAIS phenotype, but the correlation is less defined in PAIS. CAIS presents typically as primary amenorrhoea in an adolescent female and less commonly in infancy with bilateral inguinal/labial swellings due to testes. The differential diagnosis in CAIS is limited, whereas in PAIS, numerous other causes of DSD can also produce the typical phenotype of micropenis, severe hypospadias and bifid scrotum. Management issues in CAIS involve timing of gonadectomy, appropriate hormone replacement therapy and assessment of the need for vaginal dilation or rarely, vaginal surgery. The risk of gonadal germ cell tumor is low during childhood and adolescence but increases in later adulthood. Expert psychological counseling is mandatory to manage the disconnect between chromosomal, gonadal and phenotypic sex and to choreograph the evolving process of disclosure from late childhood through to maturity. It is implicit that management in AIS requires a multidisciplinary team and engagement with patient advocacy groups.

Healthy birth after testicular extraction of sperm and ICSI from an azoospermic man with mild androgen insensitivity syndrome caused by an androgen receptor partial loss‐of‐function mutation

The androgen receptor (AR) is essential for the development and maintenance of the male phenotype, and for spermatogenesis. Mutations in the AR gene cause a wide variety of androgen insensitivity syndromes (AIS), ranging from complete feminization to phenotypic males with infertility. We report the first birth achieved after intracytoplasmic sperm injection (ICSI) with sperm from an azoospermic man with an AR mutation associated with mild AIS (MAIS). A couple with primary infertility was referred to our centre. The man had azoospermia with testicular hypotrophy and an undervirilized phenotype despite a normal plasma testosterone level. His androgen sensitivity index and serum anti-mullerian hormone (AMH) levels were elevated, pointing to AIS. Molecular analysis of the AR gene revealed a point mutation resulting in an F754S substitution (renumbered F755S in the 2012 McGill University AR gene database), in the ligand-binding domain of the protein, and further analysis indicated impaired receptor function. After genetic counselling of the couple, oocytes were retrieved after controlled ovarian hyperstimulation, and sperm were obtained simultaneously by testicular extraction for ICSI. Nine embryos were obtained. Two were transferred and two were suitable for cryopreservation. A pregnancy was obtained and a healthy girl, carrying the F754S AR mutation, was born at 37 weeks of gestation. AR and AMH were detected by immunohistochemistry in the patient's testicular specimens. AMH immuno-staining was intense in tubules without spermatogenesis and weak in those with ongoing spermatogenesis. A healthy child can be obtained by testicular extraction and ICSI despite azoospermia in MAIS. The parents must be informed of the X-linked transmission of the mutation to their descendants. The relationship between AR signalling, testicular AMH expression and spermatogenesis in this patient is discussed.

Identification of a novel mutation in exon 1 of androgen receptor gene in an azoospermic patient with mild androgen insensitivity syndrome: case report and literature review

To report a case of an azoospermic subject with mild androgen insensitivity syndrome (MAIS) and review the relevant literature. Case report. Academic research hospital. A 49-year-old man with undermasculinized features and a history of cryptorchidism and azoospermia. Hormonal evaluation and genetic testing of the androgen receptor gene (AR). Hormonal levels and sequence chromatogram of the proband and his mother. We found total T in the normal range and high levels of gonadotropins. Karyotype was 46,XY. Genetic testing identified a novel mutation of exon 1 of AR, which resulted in an alanine to serine substitution in the transactivation domain at codon 240 (A240S). Fourteen other mutations of exon 1 of AR have been associated with MAIS to date. The novel mutation A240S of AR is involved in MAIS, a syndrome associated with azoospermia.