Novel mutation in the ligand-binding domain of the androgen receptor gene (1790p) associated with complete androgen insensitivity syndrome (original) (raw)
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The Journal of Clinical Endocrinology & Metabolism, 2002
Mutations in the X-linked androgen receptor (AR) gene cause the androgen insensitivity syndrome by impairing androgendependent male sexual differentiation to varying degrees. Complete androgen insensitivity (CAIS) yields an external female phenotype, whereas affected cases of partial androgen insensitivity have various ambiguities of the genitalia. Here we describe a 46,XY phenotypically female patient with all of the characteristics of CAIS, i.e. primary amenorrhea, no axillary or pubic hair, female external genitalia, no uterus, and undescended testes. Defects in testosterone and dihydrotestosterone synthesis were excluded. The molecular basis of the disease was clarified by means of direct sequencing of PCR-amplified exonic fragments of the AR gene. An A to C transition in exon 4 of the AR gene led to a novel missense His 689 Pro mutation in the ligand-binding domain of the AR protein. Functional studies demonstrated that the mutated AR is unable to efficiently bind its natural ligand dihydrotestosterone and to trans-activate known androgen response elements. Analysis of the structural consequences of the His 689 Pro substitution suggests that this mutation is likely to perturb the conformation of the second helix of the AR ligand-binding domain, which contains residues critical for androgen binding.
The Journal of Clinical Endocrinology & Metabolism, 2000
Androgen insensitivity syndrome (AIS) is the most common single entity that results in male under-masculinization, but large cohort studies of AIS have rarely been performed. Over the last decade, nationwide cooperation between pediatric endocrinologists in the United Kingdom has allowed the creation of a database of cases of intersex and ambiguous genitalia where detailed clinical information on every notified case has been collected via a questionnaire. Among the 816 entries recorded by January 1999, there were 105 clinically diagnosed cases of complete AIS (CAIS) and 173 cases of partial AIS (PAIS). A masculinization score was devised by scoring the external phenotype, and a score of 12 represented normal masculinization. Androgen receptor (AR) binding was determined by studying binding capacity (B max) and receptor affinity (K d), and cases were classified as either zero, abnormal, or normal binding. Mutation screening of all eight exons of the AR gene was performed by single-strand conformational polymorphism analysis, followed by direct DNA sequencing. All cases of PAIS presented within the first month of birth. The median age at presentation of children with CAIS was 1 yr (P10,P90: 0.1,10.4). The testes were palpable in the labioscrotal folds or the inguinal region in 77% and 41% of cases of CAIS and PAIS, respectively. There was marked overlap between the masculinization score of those children with PAIS reared as girls [2.5(P10,P90:1, 6)] and those reared as boys [3(P10,P90:2, 7.5)]. Gonadectomy was performed prepubertally in 66% and postpubertally in 29% of the cases of CAIS.
Androgen insensitivity syndrome: clinical features and molecular defects
HORMONES, 2008
The end-organ resistance to androgens has been designated as Androgen Insensitivity Syndrome (AIS), an X-linked disorder caused by mutations in the Androgen Receptor (AR) gene. It is generally accepted that defects in the AR gene prevent the normal development of both internal and external genital structures in 46,XY individuals, causing a variety of phenotypes ranging from male infertility to completely normal female external genitalia. Precise diagnosis requires clinical, hormonal and molecular investigation and is of great importance for appropriate gender assignment and management in general. The complexity of phenotypic presentation of AIS with genotype-phenotype variability of identical mutations complicates both the diagnostic procedure and genetic counseling of the affected families. More than 400 different AR gene mutations have thus far been reported but the receptor structure-function relationship and its phenotypic outcome is not yet fully understood. This review focuses on the clinical features and molecular pathophysiology of AIS and explores the relationship of the molecular defects in the AR gene to their clinical expression.
Eight novel mutations of the androgen receptor gene in patients with androgen insensitivity syndrome
Journal of Human Genetics, 2001
Androgen insensitivity syndrome (AIS) is an X-linked genetic disorder of male sexual differentiation caused by mutations in the androgen receptor (AR) gene. A reliable genotype-phenotype correlation in these patients does not exist as yet. Here we report the molecular studies performed on eight individuals with AIS. Exon-specific polymerase chain reaction (PCR), single-strand conformation polymorphism, and sequencing analyses, were performed in exons 2 to 8 of the AR gene. In one case, total cellular RNA was extracted from genital skin fibroblasts and reverse transcriptase-PCR was performed. Six different point mutations leading to amino acid substitutions (P682T, Q711E, G743E, F827V, H874R, D879Y), one splicejunction mutation (gAEc at ϩ5, exon 6/intron 6), and a missense mutation without amino acid substitution (S888S) were identified. All mutations, including a de novo mutation, were previously undescribed on the steroid binding domain. Of the eight mutations identified, four led to a complete female phenotype (codons 743, 827, 874 and the donor splice site ϩ5), two were detected in phenotypic females with partial virilization (codons 682 and 711), and two were present in phenotypic male subjects with undervirilized external genitalia, thus indicating that all of these sites determine AR functional activity.
Endocrine Journal, 2008
Mutations in the X-linked AR gene cause androgen insensitivity syndrome (AIS) by impairing androgendependent male sex differentiation to various degree. Here we describe a partial AIS patient with confliction with the assigned female sex. Although the patient was noticed to have ambiguous genitalia at birth, the patient was reared as a female with no medical intervention. At the age of 31 years, the patient visited us because the patient was dissatisfied with the assigned female sex. The patient was treated with systemic testosterone and topical dihydrotestosterone, but the external genitalia responded only minimally to the treatment. The genetic analysis revealed a novel missense K580R mutation in the P-box of the DNA-binding domain of androgen receptor, which was the first missense mutation shared by AIS and prostate cancer. Although the best predictor of the adult gender identity is documented to be the initial gender assignment in patients with partial AIS as well as those with complete AIS, deciding gender assignment for infants with partial AIS is still challenging.
The Journal of Steroid Biochemistry and Molecular Biology, 2017
Androgen insensitivity syndrome (AIS) is the most common cause of 46,XY disorders of sex development (46,XY DSD). This syndrome is an X-linked inheritance disease and it is caused by mutations in the human androgen receptor (AR) gene. Non-synonymous point AR mutations are frequently described in this disease, including in the complete phenotype. We present a novel synonymous mutation in the human AR gene (c.1530C>T) in four 46,XY patients from two unrelated families associated with complete androgen insensitivity syndrome (CAIS). The analysis of mRNA from testis showed that synonymous AR mutation changed the natural exon 1 donor splice site, with deletion of the last 92 nucleotides of the AR exon 1 leading to a premature stop codon 12 positions ahead resulting in a truncate AR protein. Linkage analyses suggested a probable founder effect for this mutation. In conclusion, we described the first synonymous AR mutation associated with CAIS phenotype, reinforcing the disease-causing role of synonymous mutations DXS986
Journal of Molecular Medicine, 2005
Androgen insensitivity syndrome (AIS) is characterized by deficient or absent virilization in 46,XY individuals despite normal or even elevated androgen levels. AIS is usually caused by mutations in the androgen receptor (AR) gene. We aimed at contrasting clinical, biochemical, and molecular genetic characteristics of three patients (P1-P3) with clinically evident partial (P1) and complete (P2, P3) AIS with and without AR gene mutations. AR expression was studied in cultured genital skin fibroblasts (GSF) by Western immunoblotting, ligand binding analyses, Northern blotting, semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), and RT-PCR spanning exons 1-8. AR gene DNA sequence was analyzed by single-strand conformation analysis (SSCA), and DNA sequencing. GSF revealed reduced (P1) or absent (P2, P3) ligand binding. Northern blots showed either slightly reduced hybridization of the 10.5-kb AR transcript (P3) or no hybridization (P1, P2), as confirmed by semiquantitative RT-PCR. RT-PCR spanning exons 1-8 detected single AR mRNA bands in P1-P3 excluding splicing errors. Western analyses showed either low (P1) or no (P2, P3) AR protein. While SSCA initially did
Journal of Andrology, 2009
Complete androgen insensitivity syndrome is an Xlinked inherited disorder caused by mutations in the androgen receptor (AR) gene. Using polymerase chain reaction single-strand DNA conformational polymorphism and DNA sequencing, we identified a novel nonsense mutation in exon 1 of the AR gene in 2 Iranian brothers with complete androgen insensitivity syndrome. Despite a normal 46,XY karyotype, testes, and normal to elevated plasma levels of testosterone, they were born with female external genitalia and phenotype. This new mutation, a T-to-A transversion in exon 1, causes amino acid change of tyrosine (TAT) to ochre stop codon (TAA) at position 514 of the AR polypeptide. The Y514X mutation is located in a region that is normally important for the formation and function of the hormone receptor complex. We conclude that the novel Y514X mutation in the androgen receptor is the cause of complete androgen insensitivity syndrome in this family.