Mutational analysis of the androgen receptor gene in two Chinese families with complete androgen insensitivity syndrome

In Silico Analysis of Functional SNPs in Genes of Complete Androgen Insensitivity Syndrome (CAIS): A Retrospective, Case-Control Study

Background

Complete androgen insensitivity syndrome (CAIS) is one of the categories of androgen insensitivity syndrome (AIS) described as complete failure of the cell to react to androgens with external genitalia of a normal female. People with AIS condition are genetically male, with XY karyotype in each cell, but their bodies are unable to respond to male sex hormones (called androgens). It is associated with infertility as well as developing cancerous conditions. The genetic association of CAIS involves polymorphism of genes such as NR5A1, SOX9, SRD5A2, CBX2, GATA4, and SRY. Their mutation and participation in genetics of CAIS can be studied by Single Nucleotide polymorphism (SNP) analysis which is a way to detect genetic variations. SNP in coding region leads to synonymous and non-synonymous mutations. Hence, this study highlights analysis of SNPs associated with CAIS. Our aim is to study SNP analysis of NR5A1, SOX9, SRD5A2, CBX2, GATA4, SRY genes in Complete Androgen Insensitivity Syndrome.

Methods

SIFT and Polyphen analysis was performed for all the genes and samples were subjected for PCR-SSCP technique.

Results

SNPs were analyzed for the genes associated with CAIS. Benign and damaging SNPs were identified. DNA Samples were amplified using PCR technique and they will be analyzed using Single-strand conformation polymorphism (SSCP).

Conclusions

As SNPs have decreased stability, damaging and benign character, they can be used as candidate hallmarks in study of Complete Androgen Insensitivity Syndrome.

Case Report: a Novel Nonsense Mutation in the Androgen Receptor Gene Causing the Complete Androgen Insensitivity Syndrome

Androgen insensitivity syndrome (AIS) is a rare X-linked genetic disorder caused by mutations in the androgen receptor (AR) gene. AIS can be divided into partial type (PAIS), mild type (MAIS), and complete type (CAIS) based on the degree of androgen insensitivity. CAIS is characterized by a male genotype and a complete female phenotype. A 10-year-old child presented with a bilateral inguinal mass for 9 years. Physical examination revealed a complete feminine genital appearance and a painless mass in bilateral inguinal area. Pelvic magnetic resonance imaging (MRI) revealed long T1 and T2 elliptic signal nodules in bilateral inguinal area, absence of uterus-ovary signal and a short blind end of the vagina. Chromosomal analyzes manifested a 46, XY karyotype. By analyzing the above clinical data, the preliminary diagnosis of CAIS was confirmed. Then laparoscopic bilateral gonadectomy was performed. The histological examination of resected gonad showed it consisted of dysplastic testicular tissue and no signs of malignancy were observed. Sanger sequencing revealed the presence of a hemizygous mutation c.927 T > G (p. Tyr309*) in exon 1 of the AR gene. This is the first report of a novel nonsense mutation.

Novel androgen receptor gene variant containing a frameshift mutation in a patient with complete androgen insensitivity syndrome

A variety of mutations in the androgen receptor (AR) gene are linked to androgen insensitivity syndrome (AIS). AIS is the most common specific cause of 46, XY disorder in sex development. Here, we reported a patient which presented as a female with 46, XY karyotype and normal female external genitalia. The patient was diagnosed with complete AIS caused by a novel mutation (NM_000044, c.2678-2726del, p. Pro893Leufs*35) in the AR gene. Targeted exome sequencing was used to detect the patient's androgen receptor gene mutations. Sanger sequencing was used to validate the mutation. This study showed that a novel mutation of the AR gene can cause complete AIS; the study also broadened the AR mutation spectrum and indicated that targeted exome sequencing could help facilitate the diagnosis of complicated disorders in sexual development.

Androgen signaling uses a writer and a reader of ADP-ribosylation to regulate protein complex assembly

Androgen signaling through the androgen receptor (AR) directs gene expression in both normal and prostate cancer cells. Androgen regulates multiple aspects of the AR life cycle, including its localization and post-translational modification, but understanding how modifications are read and integrated with AR activity has been difficult. Here, we show that ADP-ribosylation regulates AR through a nuclear pathway mediated by Parp7. We show that Parp7 mono-ADP-ribosylates agonist-bound AR, and that ADP-ribosyl-cysteines within the N-terminal domain mediate recruitment of the E3 ligase Dtx3L/Parp9. Molecular recognition of ADP-ribosyl-cysteine is provided by tandem macrodomains in Parp9, and Dtx3L/Parp9 modulates expression of a subset of AR-regulated genes. Parp7, ADP-ribosylation of AR, and AR-Dtx3L/Parp9 complex assembly are inhibited by Olaparib, a compound used clinically to inhibit poly-ADP-ribosyltransferases Parp1/2. Our study reveals the components of an androgen signaling axis that uses a writer and reader of ADP-ribosylation to regulate protein-protein interactions and AR activity.

Complete androgen insensitivity syndrome caused by c.1769-1G > C mutation and activation of a cryptic splice acceptor site in the androgen receptor gene

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 recessive genetic disease characterized by resistance to the actions of androgens in an individual with a male karyotype and it is caused by mutations in the androgen receptor (AR) gene. We evaluated two siblings with primary amenorrhea, normal secondary sex characteristics, absence of uterus and ovaries, intra-abdominal testis, and elevated testosterone levels. Sequence analysis of the AR gene revealed a splice acceptor site mutation in intron 2 (c.1769-1G > C). The analysis of mRNA showed that this mutation resulted in the activation of a cryptic splice acceptor site located in intron 2 and in the synthesis of an aberrant mRNA transcript with 69 nucleotides insertion between exon 2 and exon 3, leading to an insertion of 23 amino acids in the AR protein instead of generating a premature termination codon. The additional 23 amino acids insertion affects AR intracellular trafficking by impairing its translocation from the cytoplasm to the nucleus after hormone stimulation. The c.1769-1G > C mutation provides new insights into the molecular mechanism involved in splicing defects and expands the spectrum of mutations associated with the androgen insensitivity syndrome.