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

Unveiling the critical role of androgen receptor signaling in avian sexual development

Gonadal hormone activities mediated by androgen and estrogen receptors, along with cell-autonomous mechanisms arising from the absence of sex-chromosome dosage compensation, are key factors in avian sexual development. In this study, we generate androgen receptor (AR) knockout chickens (AR-/-) to explore the role of androgen signaling in avian sexual development. Despite developing sex-typical gonads and gonadal hormone production, AR-/- males and females are infertile. While few somatic sex-specific traits persist (body size, spurs, and tail feathers), crucial sexual attributes such as comb, wattles and sexual behaviors remain underdeveloped in both sexes. Testosterone treatment of young AR-/- males fails to induce crow behavior, comb development, or regression of the bursa of Fabricius, which are testosterone-dependent phenotypes. These findings highlight the significance of androgen receptor mechanisms in fertility and sex-specific traits in chickens, challenging the concept of a default sex in birds and emphasizing the dominance of androgen signaling in avian sexual development.

[Value of the human chorionic gonadotropin stimulation test in the diagnosis of disorder of sexual development in children]

OBJECTIVES

To investigate the value of the human chorionic gonadotropin (hCG) stimulation test in the diagnosis of disorder of sexual development (DSD) in children.

METHODS

A retrospective analysis was conducted on 132 children with DSD. According to the karyotype, they were divided into three groups: 46,XX group (n=10), 46,XY group (n=87), and sex chromosome abnormality group (n=35). The above groups were compared in terms of sex hormone levels before and after hCG stimulation test, and the morphological manifestation of the impact of testicular tissue on the results of the hCG stimulation test was analyzed.

RESULTS

There was no significant difference in the multiple increase of testosterone after stimulation among the three groups (P>0.05). In the 46,XY group, the children with 5α-reductase type 2 deficiency had a testosterone-to-dihydrotestosterone ratio higher than that of the 46,XY DSD children with other causes. Morphological analysis showed that DSD children with testicular tissue demonstrated a significantly higher multiple increase in testosterone after stimulation compared to children without testicular tissue (P<0.05).

CONCLUSIONS

The hCG stimulation test has an important value in assessing the presence and function of testicular interstitial cells in children with different types of DSD, and it is recommended to perform the hCG stimulation test for DSD children with unclear gonadal type.

Small Indels in the Androgen Receptor Gene: Phenotype Implications and Mechanisms of Mutagenesis

CONTEXT

Despite high abundance of small indels in human genomes, their precise roles and underlying mechanisms of mutagenesis in Mendelian disorders require further investigation.

OBJECTIVE

To profile the distribution, functional implications, and mechanisms of small indels in the androgen receptor (AR) gene in individuals with androgen insensitivity syndrome (AIS).

METHODS

We conducted a systematic review of previously reported indels within the coding region of the AR gene, including 3 novel indels. Distribution throughout the AR coding region was examined and compared with genomic population data. Additionally, we assessed their impact on the AIS phenotype and investigated potential mechanisms driving their occurrence.

RESULTS

A total of 82 indels in AIS were included. Notably, all frameshift indels exhibited complete AIS. The distribution of indels across the AR gene showed a predominance in the N-terminal domain, most leading to frameshift mutations. Small deletions accounted for 59.7%. Most indels occurred in nonrepetitive sequences, with 15.8% situated within triplet regions. Gene burden analysis demonstrated significant enrichment of frameshift indels in AIS compared with controls (P < .00001), and deletions were overrepresented in AIS (P < .00001).

CONCLUSION

Our findings underscore a robust genotype-phenotype relationship regarding small indels in the AR gene in AIS, with a vast majority presenting complete AIS. Triplet regions and homopolymeric runs emerged as prone loci for small indels within the AR. Most were frameshift indels, with polymerase slippage potentially explaining half of AR indel occurrences. Complex frameshift indels exhibited association with palindromic runs. These discoveries advance understanding of the genetic basis of AIS and shed light on potential mechanisms underlying pathogenic small indel events.

Epithelial and mesenchymal fate decisions in Wolffian duct development

Wolffian ducts (WDs) are the paired embryonic structures that give rise to internal male reproductive tract organs. WDs are initially formed in both sexes but have sex-specific fates during sexual differentiation. Understanding WD differentiation requires insights into the process of fate decisions of epithelial and mesenchymal cells, which are tightly coordinated by endocrine, paracrine, and autocrine signals. In this review, we discuss current advances in understanding the fate-decision process of WD epithelial and mesenchymal lineages from their initial formation at the embryonic stage to postnatal differentiation. Finally, we discuss aberrant cell differentiation in WD abnormalities and pathologies and identify opportunities for future investigations.

Complete androgen insensitivity syndrome: a case report and literature review

Complete androgen insensitivity syndrome (CAIS) is a rare disease that can be easily misdiagnosed. Before puberty, this condition is easily misdiagnosed as an inguinal hernia. This case report describes a 31-year-old phenotypically female patient with CAIS who was misdiagnosed twice previously with an inguinal hernia. Her karyotype analysis showed that she was 46, XY. She underwent a bilateral gonadectomy and long-term hormone replacement therapy. A Leydig cell tumour of the right testis was diagnosed postoperatively. This report also reviews the current understanding of the diagnosis and treatment of CAIS.

Case report: Identification of a frameshift mutation in GC enrichment and the GCC repeat region of the androgen insensitivity receptor (AR) gene in a patient with complete androgen insensitivity syndrome by whole-exome sequencing (WES) combined with specific PCR and deep sequencing

Background: Androgen insensitivity syndrome (AIS) is an X-linked recessive hereditary disease caused due to a reduced or absent function of the androgen receptor (AR) protein encoded by the AR gene (OMIM-Gene# 313,700). Genetic testing is important in the diagnosis, clinical management, and prevention of AIS (MIM# 300,068). The AR (HGNC: 644) pathogenic variant detection rate ranges from 65% to 95% for patients with complete AIS (CAIS) and 40%-45% for patients with partial androgen insensitivity syndrome (PAIS). Identification of a pathogenic mutation in the AR confirms the diagnosis of AIS, especially in the milder forms that may have a phenotypic overlap with other disorders of sex development. Improvement of the molecular diagnostic rate of AIS is urgently required in clinical practice. We reported the results of the molecular diagnosis of a patient with CAIS who failed previously in either the traditional Sanger sequencing or next-generation sequencing (NGS). Using whole-exome sequencing (WES) combined with a special polymerase chain reaction (PCR) and deep sequencing, we successfully identified a pathogenic variant, a hemizygous mutation (c.1395-1396insGA), in the GC-enriched and unstable GCC repeat regions of the AR gene of the proband. Conclusion: The results may be advantageous for the improvement of the detection rate of AIS, as well as other inherited disorders whose disease-causing genes contain GC-enriched and unstable GCC repeat regions.