A systematic review of the association between the age of onset of spinal bulbar muscular atrophy (Kennedy's disease) and the length of CAG repeats in the androgen receptor gene

Introduction

Spinal bulbar muscular atrophy (SBMA) is an X-linked recessive motor neuron disorder caused by the presence of ≥38 CAG repeats in the androgen receptor gene. Existing literature indicates a relationship between CAG repeat number and the onset age of some motor symptoms of SBMA. This review explores the effect of larger versus shorter CAG repeats on the age of weakness onset in male SBMA patients.

Methods

Three databases (October 2021; MEDLINE, SCOPUS, and Web of Science), Cambridge University Press, and Annals of Neurology were searched. 514 articles were initially identified, of which 13 were included for qualitative synthesis.

Results

Eleven of the thirteen articles identified a statistically significant inverse correlation between CAG repeat length and age of weakness onset in SBMA. Five studies indicated that SBMA patients with between 35 and 37 CAG repeats had an older age of weakness onset than patients with over 40 CAG repeats. The minimum number of CAG repeats associated with weakness was in the mid-to-late thirties.

Conclusion

Identification of a relationship between CAG repeat number and age of weakness may enable earlier detection and intervention for SBMA. In the future, studies should use interviews, chart reviews, and standardized scoring methods to reduce effects of retrospective bias.

Complete androgen insensitivity syndrome caused by the c.2678C>T mutation in the androgen receptor gene: A case report

BACKGROUND

Androgen insensitivity syndrome is an X-linked recessive genetic disease caused by mutations in the androgen receptor gene (AR). However, the underlying molecular mechanisms for the majority of AR variants remain unclear. In this study, we identified a point variant in three patients with complete androgen insensitivity syndrome (CAIS), summarized the correlation analysis, and performed a literature review.

CASE SUMMARY

The proband was raised as a girl. In infancy, she was first referred to hospital with a right inguinal hernia. Ultrasonography revealed the absence of a uterus and ovaries, and a testis-like structure located at the inguinal canal. Further diagnostic workup detected a 46, XY karyotype, and fluorescence in situ hybridization analysis showed the presence of the SRY gene. Histological analysis revealed the excised tissue to be testicular. Twelve years later, she was admitted to our hospital with a lack of breast development. Her pubic hair and breasts were Tanner stage I. She had normal female external genitalia. Blood hormone tests showed normal testosterone levels, low estradiol levels, and high gonadotropin levels. Her two siblings underwent similar examinations, and all three had a rare hemizygous missense mutation in AR: c.2678C>T. In vitro functional analyses revealed decreased nuclear translocation in AR-c.2678C>T mutation cells.

CONCLUSION

This case of CAIS was caused by an AR variant (c.2678C>T). Functional studies showed impaired nuclear translocation ability of the mutant protein.

Clinical, Biochemical, and Molecular Characterization of Indian Children with Clinically Suspected Androgen Insensitivity Syndrome

This study describes the clinical, biochemical, and molecular characteristics of Indian children with 46,XY DSD and suspected androgen insensitivity syndrome (AIS). Fifty children (median age 3.0 years, range 0-16.5 years) with 46,XY DSD and a suspected diagnosis of AIS were enrolled. Sanger sequencing was performed to identify pathogenic variants in the androgen receptor (AR) gene and to study genotype-phenotype correlations. All 5 (100%) patients with CAIS and 14/45 (31%) patients with PAIS had pathogenic/likely pathogenic variants in the AR gene (overall, 14 different variants in 19 patients; 38.8%). There was no significant difference in clinical (cryptorchidism, hypospadias, or external masculinizing score) or biochemical parameters (gonadotropins and testosterone) between patients with or without pathogenic variants. However, patients with AIS were more likely to have a positive family history, be assigned female gender at birth, and present with gynaecomastia at puberty. Three novel pathogenic/likely pathogenic variants, including one splice donor site variant c.2318+1G>A, one frameshift variant p.H790Lfs*40, and one missense variant p.G821E, were identified in 3 patients with CAIS. The missense variant p.G821E was predicted as deleterious, damaging, disease-causing, and likely functionally inactive by in silico analysis and protein modelling study. Two previously not reported pathogenic/likely pathogenic variants, including p.R386H and p.G396R, were identified in patients with PAIS. This study contributes in expanding the spectrum of pathogenic variants in the AR gene in patients with AIS. Only 31% patients with a provisional diagnosis of PAIS had pathogenic variants in the AR gene, suggesting other possible mechanisms or candidate genes may be responsible for such a phenotypic presentation.

Shorter androgen receptor polyQ alleles protect against life-threatening COVID-19 disease in European males

Background

While SARS-CoV-2 similarly infects men and women, COVID-19 outcome is less favorable in men. Variability in COVID-19 severity may be explained by differences in the host genome.

Methods

We compared poly-amino acids variability from WES data in severely affected COVID-19 patients versus SARS-CoV-2 PCR-positive oligo-asymptomatic subjects.

Findings

Shorter polyQ alleles (≤22) in the androgen receptor (AR) conferred protection against severe outcome in COVID-19 in the first tested cohort (both males and females) of 638 Italian subjects. The association between long polyQ alleles (≥23) and severe clinical outcome (p = 0.024) was also validated in an independent cohort of Spanish men <60 years of age (p = 0.014). Testosterone was higher in subjects with AR long-polyQ, possibly indicating receptor resistance (p = 0.042 Mann-Whitney U test). Inappropriately low serum testosterone level among carriers of the long-polyQ alleles (p = 0.0004 Mann-Whitney U test) predicted the need for intensive care in COVID-19 infected men. In agreement with the known anti-inflammatory action of testosterone, patients with long-polyQ and age ≥60 years had increased levels of CRP (p = 0.018, not accounting for multiple testing).

Interpretation

We identify the first genetic polymorphism that appears to predispose some men to develop more severe disease. Failure of the endocrine feedback to overcome AR signaling defects by increasing testosterone levels during the infection leads to the polyQ tract becoming dominant to serum testosterone levels for the clinical outcome. These results may contribute to designing reliable clinical and public health measures and provide a rationale to test testosterone as adjuvant therapy in men with COVID-19 expressing long AR polyQ repeats.

Funding

MIUR project “Dipartimenti di Eccellenza 2018-2020” to Department of Medical Biotechnologies University of Siena, Italy (Italian D.L. n.18 March 17, 2020) and “Bando Ricerca COVID-19 Toscana” project to Azienda Ospedaliero-Universitaria Senese. Private donors for COVID-19 research and charity funds from Intesa San Paolo.

Association of trinucleotide repeat polymorphisms CAG and GGC in exon 1 of the Androgen Receptor gene with male infertility: a cross-sectional study

BACKGROUND

Infertility is a global problem that brings with serious sexual and social consequences that strain the health sector and society. The expansion of CAG & GGC repeats in androgen receptor (AR) gene Ensembl number; ENSG00000169083 may leads to reduced fertility. Our objective was to determine association of CAG and GGC repeats with altered sperm parameters in male infertile subjects.

MATERIALS AND METHODS

It was a cross sectional study conducted at Aga Khan University, Karachi Pakistan. A total of 376 males were recruited, out of which group A (N=208) and group B (N=168) comprised of subjects with normal and altered sperm parameters respectively from 18 to 60 years. Numbers of CAG and GGC repeats were determined by using PCR amplification and sequence analysis using Molecular Evolutionary Genetic Analysis (MEGA) software version 6.0. Statistical analysis was done using SPSS version 20 and p-value of < 0.05 were considered significant.

RESULTS

The mean androgen receptor gene CAG repeats were significantly longer in males with altered sperm parameters as compared to male subjects with normal sperm parameters (p< 0.001). There was no significant difference found for GGC repeats for subjects with altered sperm parameters.

CONCLUSIONS

Longer CAG length corresponded to greater severity of spermatogenic defect and may lead to subfertility recommendations.

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

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

Comprehensive Analysis of AR Alterations in Circulating Tumor DNA from Patients with Advanced Prostate Cancer

BACKGROUND

Somatic alterations in circulating tumor DNA (ctDNA) may be associated with treatment response or prognosis in prostate cancer (PCa). The goal was to characterize androgen receptor gene (AR) amplifications and mutations detected in ctDNA from patients with PCa and to further understand the somatic genetic heterogeneity of advanced prostate cancer.

PATIENTS AND METHODS

This study included a heterogeneous group of 892 patients with advanced PCa (predominantly castrate-resistant prostate cancer) with AR alterations detected in ctDNA that underwent next-generation sequencing of 54 to 73 genes via Guardant360 testing (Guardant Health, Inc., Redwood City, CA). Distribution and summary of AR alterations detected, the association of AR alterations with other genes, and a pathway analysis are reported.

RESULTS

The median absolute plasma copy number of AR amplifications was 3.3 (range, 1.2-165.2). Many patients had multiple AR mutations; a total of 112 unique mutations were identified in AR, including L702H (25%), T878A (14%), H875Y (11%), W742C (8%), W742L (4%), F877L (2%), and T878S (2%). Other ctDNA gene alterations in the Guardant assays included TP53 (50%), MYC (34%), BRAF (32%), PIK3CA (29%), MET (25%), CDK6 (26%), EGFR (24%), FGFR1 (21%), and APC (12%). Many of these non-AR alterations are not tissue verified in other studies. AR amplification cosegregated with alterations in MYC (p < .001), BRAF (p < .001), PIK3CA (p < .001), MET (p < .001), CDK6 (p < .001), EGFR (p < .001), FGFR1 (p = .391), and more. Alterations in APC were significantly associated with mutations in AR (p < .001).

CONCLUSION

Several AR alterations and concomitant non-AR alterations that associate with drug resistance were detected. These findings provide additional insights into the heterogeneity of advanced prostate cancer.

IMPLICATIONS FOR PRACTICE

The goal was to characterize androgen receptor gene (AR) amplifications and mutations detected in circulating tumor DNA (ctDNA) from patients with prostate cancer in relation to non-AR gene alterations detected in the ctDNA landscape. The study included 892 patients with prostate cancer with AR alterations in ctDNA. AR alterations were significantly associated with other gene alterations detected in ctDNA. The common AR mutations found are linked to resistance to abiraterone, enzalutamide, or bicalutamide. Characterization of the circulating AR landscape and gene alterations provides potential additional insight into the somatic genetic heterogeneity of advanced prostate cancer.

Vitamin C suppresses ovarian pathophysiology in experimental polycystic ovarian syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), also known as the Stein-Leventhal syndrome is one of the most common causes of anovulation, infertility and hyperandrogenism in women, affecting between 5-10 % of women of reproductive age (12-35 years) worldwide. Despite substantial effort to define the cause of PCOS, its pathophysiology remains poorly understood. Consequently, determining the mechanisms of PCOS and the possible treatment is the major goal of medical research in endocrine and reproductive physiology.

AIM

To investigate the mechanism of ovarian metabolic changes in dehydroepiandrosterone (DHEA)-induced polycystic ovary in Wistar rats treated with vitamin C.

METHODS

Twenty-eight immature female Wistar rats weighing (16-21 g) were randomly divided into four groups (n = 7/group): group I served as control and was given water, group II were injected with DHEA (6 mg/100 g in 0.2 ml corn oil subcutaneously to induce PCOS condition), group III received 150 mg/kg BW of Vitamin C orally, group IV were co-administered with 6 mg/kg BW DHEA in 0.2 ml of corn oil subcutaneously and 150 mg/kg BW of Vitamin C orally. All treatments lasted for 15 days. Twenty-four hours after the last administration, the rats were sacrificed by cervical dislocation. Blood samples and ovaries were collected for reproductive hormonal analysis, biochemical and histopathological analysis. The expressions of mRNA androgen receptor gene in the ovary were determined by real-time reverse transcriptase polymerase chain reaction. All data were analysed using one-way ANOVA.

RESULTS

There was a significant decrease (p < 0.05) in the antioxidant and metabolic enzyme activity in the DHEA treated group compared with the control group. DHEA co-administration with Vitamin C showed a significant decrease in Malondialdehyde, cytokines and Estrogen and a significant increase (p < 0.05) in antioxidant and metabolic enzymes compared with DHEA treated group only. The histopathological evaluation demonstrates a reduction in cystic and atretic ovaries, increased expression of Bcl₂ and E-Cadherin with a reduction in Bax expression in the group co-administered with DHEA and Vitamin C. The DHEA group showed overexpression of mRNA Androgen Receptor gene in the ovaries compared to the control group.

CONCLUSION

This study shows that Vitamin C plays a protective role against DHEA-Induced Polycystic Ovary in Wistar rats via its antioxidant and anti-apoptotic mechanisms.

Clinical manifestations and AR gene mutations in Kennedy's disease

Kennedy's disease, resulted from the expansion of a CAG repeat in exon 1 of androgen receptor (AR) gene, is a motor neuron degenerative disease in the brainstem and spinal cord with the slow development of facial, bulbar, and limb muscle degeneration. To investigate the clinical manifestations and gene mutations in Han Chinese patients with Kennedy's disease. The clinical manifestations of 5 male Han Chinese patients including 2 probands and their relatives from 2 families and 1 sporadic case were retrospectively studied. The CAG repeats in the first exon of AR were screened in 5 Han Chinese people including 2 probands and their healthy relatives from 2 families and 1 sporadic case by polymerase chain reaction (PCR) and direct sequencing. The average age at onset of Kennedy's disease was 48.20 ± 8.70 (mean ± SD) years and the average duration was 7.60 ± 5.32 years. All the patients showed slow onset and progressive weakness, wasting, and fasciculations of the whole body. Four patients demonstrated decreased fertility and 1 patient showed mild gynecomastia. Serum creatine kinase and testosterone levels were elevated mildly in 2 and 1 patients, respectively. The electromyogram showed neurogenic abnormalities. Muscle magnetic resonance demonstrated reduced muscle volume and fatty infiltration. Three different enlarged CAG domains were discovered in the 2 families and 1 sporadic patient with Kennedy's disease, and the CAG repeat number was 48, 43, and 44, respectively. The clinical manifestations of Kennedy's disease in Han Chinese middle-aged men were progressive weakness and atrophy in the bulbar and spinal muscles, occasionally demonstrating incomplete androgen insensitivity syndrome. These patients were also characterized with enlarged CAG repeat number in the first exon of AR, indicating that CAG number could be used in the diagnosis of Han Chinese patients with Kennedy's disease.

Complete Androgen Insensitivity Syndrome due to Mutations in the DNA-Binding Domain of the Human Androgen Receptor Gene

Androgen insensitivity syndrome (AIS) is an X-linked recessive disorder with a 46,XY karyotype caused by alterations in the androgen receptor (AR) gene. We have identified 2 mutations in the AR gene that resulted in complete androgen insensitivity syndrome (CAIS) in 2 unrelated cases. This study includes cytogenetics, hormonal, molecular, and bioinformatics analysis including sequencing of the SRY (sex-determining region Y) and AR genes. Mutational analysis in the first case of primary amenorrhea revealed a novel nucleotide substitution (IVS2-2A>G) in the second intron of the AR gene. The mutation is located in the acceptor splice site (2 nucleotides before exon 3) and caused skipping of exon 3 and formation of an abnormal protein. The second mutation (g. 98762_98764delTCT) was identified in a case of oligoamenorrhea and caused the deletion of 1 amino acid (p.∆Phe583). Both identified mutations were located in the conserved P-box region of the DNA-binding domain which is responsible for base-specific contacts with the DNA major groove. Furthermore, a hormonal imbalance was also noticed in both cases with high levels of gonadotropins like FSH and LH in both cases. The present study concluded that both identified AR mutations are predicted to either abolish or decrease the binding ability of the AR to androgen response elements of its downstream genes.

Association between G1733A (rs6152) polymorphism in androgen receptor gene and recurrent spontaneous abortions in Mexican population

INTRODUCTION

Recurrent spontaneous abortion (RSA) is a multifactorial condition that occurs with a frequency of 0.2-5% in women of reproductive age. Among genetic factors, the single nucleotide polymorphism (SNP) G1733A in the androgen receptor (AR) gene has been associated with its presence in Greek and Iranian populations. Therefore, the aim of this study is to determine its possible association with RSA in this population.

PATIENTS AND METHODS

A total of 156 Mexican RSA (with at least 2 consecutive abortions) unrelated patients and 152 unrelated healthy women were included, the presence of karyotype anomalies in the parents as well as uterine anomalies as well as antiphospholipid antibodies was excluded in patients; while all the controls presented at least two healthy pregnancies and no abortion. In all the included women, the presence of the SNP G1733A was determined by restriction fragment length polymorphism (RFLP) technique.

RESULTS

No significant differences were observed in age between groups. The genotype GG, GA, and AA had a frequency of 0.70, 0.27, and 0.03 in patients and of 0.89, 0.10, and 0.01 in controls [corrected] (p < 0.001); while the A allele frequency was of 0.06 and 0.16 in controls and patients, respectively (p < 0.0001). The difference in allele frequency increased 10-15% when patients with primary RSA (with no live births) and with at least three abortions were included.

CONCLUSIONS

The SNP G1733A of the AR gene is significantly associated with RSA in Mexican patients. These results coincide with previous reports in other populations.

The CAG polymorphism in androgen receptor (AR) gene impacts the moral permissibility of harmful behavior in females

The moral permissibility of harm is strikingly varied among individuals. In light of the connection between testosterone levels and utilitarian moral judgment, this study examined to what extent a CAG polymorphism in the androgen receptor gene, a genetic polymorphism with the ability to regulate testosterone function, contributes to individual differences in moral judgment. Four hundred and thirty-nine Chinese Han participants completed permissibility ratings of harm in moral dilemmas and moral transgression scenarios. Results showed a significant association between the CAG polymorphism and moral permissibility of harm in females. Females with more copies of the S allele, which is associated with higher availability of testosterone, were more likely to judge harmful utilitarian acts and unintentionally harmful acts as permissible, while these effects were absent in males. The findings provide the first evidence for a link between the androgen receptor gene and moral judgment and highlight the role of androgens in moral foundations.

Heterozygous Nonsense Mutation in the Androgen Receptor Gene Associated with Partial Androgen Insensitivity Syndrome in an Individual with 47,XXY Karyotype

There are only 2 patients with 47,XXY karyotype and androgen receptor (AR) gene mutation reported in the literature, and both are diagnosed as complete androgen insensitivity syndrome (CAIS). We report a 22-year-old female with 47,XXY karyotype and atypical external genitalia. Sequencing of AR revealed the heterozygous p.Asn849Lys*32 mutation, and extensive X chromosome microsatellite analysis showed homozygosity for Xp and heterozygosity for Xq, suggesting partial X maternal isodisomy. Partial androgen insensitivity syndrome (PAIS) developed in this case, probably because of the presence of the heterozygous AR mutation and random X- inactivation of the healthy allele. This is the first report of a female patient with 47,XXY karyotype and PAIS phenotype.

Complete Androgen Insensitivity Syndrome in Three Generations of Indian Pedigree

BACKGROUND

Androgen insensitivity syndrome or testicular feminization syndrome is a rare X-linked recessive disorder, which encompasses a wide range of phenotypes that are caused by numerous different mutations in the androgen receptor gene. Complete androgen insensitivity syndrome occurs when the body cannot use androgens at all. People with this form of the condition have the external sex characteristics of females, but do not have a uterus and therefore do not menstruate and are unable to conceive a child (infertile).

METHODS

In this paper, we report three cases of familial complete androgen insensitivity syndrome who presented with primary amenorrhea.

RESULTS

Physical examination, ultrasonography studies, and biochemical, karyotype, and molecular cytogenetic analyses were conducted. Based on the findings, they were diagnosed and confirmed as having complete androgen insensitivity syndrome.

CONCLUSION

A multidisciplinary team is needed from disclosure of the diagnosis, gender assignment, surgical management, hormonal replacement therapy, to counseling and support.

A unique mosaic Turner syndrome patient with androgen receptor gene derived marker chromosome

Patients with Turner syndrome are generally characterized by having short stature with no secondary sexual characteristics. Some abnormalities, such as webbed neck, renal malformations (>50%) and cardiac defects (10%) are less common. The intelligence of these patients is considered normal. Non-mosaic monosomy X is observed in approximately 45% of postnatal patients with Turner syndrome and the rest of the patients have structural abnormalities or mosaicism involving 46,X,i(Xq), 45,X/46,XX, 45,X and other variants. The phenotype of 45,X/46,X,+mar individuals varies by the genetic continent and degree of the mosaicism. The gene content of the marker chromosome is the most important when correlating the phenotype with the genotype. Here we present an 11-year-old female who was referred for evaluation of her short stature and learning disabilities. Conventional cytogenetic investigation showed a mosaic 45,X/46,X,+mar karyotype. Fluorescence in situ hybridization showed that the marker chromosome originated from the X chromosome within the androgen receptor (AR) and X-inactive specific transcript (XIST) genes. Therefore, it is possible that aberrant activation of the marker chromosome, compromising the AR and XIST genes, may modify the Turner syndrome phenotype.

Clinical, cytogenetic and molecular analysis of androgen insensitivity syndromes from south Indian cohort and detection and in-silico characterization of androgen receptor gene mutations

Rare cases of 9 complete androgen insensitivity syndromes, 9 cases of partial androgen insensitivity syndromes and equal number of male control samples were selected for this study. Few strong variations in clinical features were noticed; Giemsa banded metaphase revealed a 46,XY karyotype and the frequency of chromosome aberrations were significantly higher when compared with control samples. DNA sequence analysis of the androgen receptor gene of androgen insensitivity syndromes revealed three missense mutations - c.C1713>G resulting in the replacement of a highly conserved histidine residue with glutamine p.(His571Glu) in DNA-binding domain, c.A1715>G resulting in the replacement of a highly conserved tyrosine residue with cysteine p.(Tyr572Cys) in DNA-binding domain and c.G2599>A resulting in the replacement of a highly conserved valine residue with methionine p.(Val867Met) in ligand-binding domain of androgen receptor gene respectively. The heterozygous type of mutations c.C1713>G and c.G2599>A observed in mothers of the patients for familial cases concluding that the mutation was inherited from the mother. The novel mutation c.C1713>G is reported first time in androgen insensitivity syndrome. In-silico analysis of mutations observed in androgen receptor gene of androgen insensitivity syndrome predicted that the substitution at Y572C and V867M could probably disrupt the protein structure and function.

Clinical Characteristics and Genotype-Phenotype Correlation of Korean Patients with Spinal and Bulbar Muscular Atrophy

PURPOSE

Spinal and bulbar muscular atrophy (SBMA) is an X-linked motor neuron disease characterized by proximal muscle weakness, muscle atrophy, and fas-ciculation. Although SBMA is not uncommon in Korea, there is only one study reporting clinical characteristics and genotype-phenotype correlation in Korean patients.

MATERIALS AND METHODS

In this study, age at the onset of symptoms, the score of severity assessed by impairment of activities of daily living milestones, and rate of disease progression, and their correlations with the number of CAG repeats in the androgen receptor (AR) gene, as well as possible correlations among clinical characteristics, were analyzed in 40 SBMA patients.

RESULTS

The median ages at onset and at diagnosis were 44.5 and 52.5 years, respectively, and median interval between onset and diagnosis and median rate of disease progression were 5.0 years and 0.23 score/year, respectively. The median number of CAG repeats in the AR gene was 44 and the number of CAG repeats showed a significant inverse correlation with the age at onset of symptoms (r=-0.407, p=0.009). In addition, patients with early symptom onset had slower rate of disease progression.

CONCLUSION

As a report with the largest and recent Korean cohort, this study demonstrates clinical features of Korean patients with SBMA and reaffirms the inverse correlation between the age at disease onset and the number of CAG repeats. Interestingly, this study shows a possibility that the rate of disease progression may be influenced by the age at onset of symptoms.

New single nucleotide variation in the promoter region of androgen receptor (AR) gene in hypospadic patients

BACKGROUND

Hypospadias is one of the most common congenital abnormalities in the male which is characterized by altered development of urethra, foreskin and ventral surface of the penis. Androgen receptor gene plays a critical role in the development of the male genital system by mediating the androgens effects.

OBJECTIVE

In present study, we looked for new variations in androgen receptor promoter and screened its exon 1 for five single nucleotide polymorphisms (SNP) in healthy and hypospadias Iranian men.

MATERIALS AND METHODS

In our study, at first DNA was extracted from patients (n=100) and controls (n=100) blood samples. Desired fragments of promoter and exon 1 were amplified using polymerase chain reaction. The promoter region was sequenced for the new variation and exone 1 screened for five SNPs (rs139767835, rs78686797, rs62636528, rs62636529, rs145326748) using restriction fragment length polymorphism technique.

RESULTS

The results showed a new single nucleotide variation (C→T) at -480 of two patients' promoter region (2%). None of the mentioned SNPs were detected in patients and controls groups (0%).

CONCLUSION

This finding indicates that new single nucleotide polymorphism in androgen receptor promoter may have role in etiology of hypospadias and development of this anomaly. This article extracted from Ph.D. thesis. (Nasim Borhani).