A missense mutation in the androgen receptor gene causing androgen insensitivity syndrome in a Chinese family

Clinical characteristics and molecular genetics of complete androgen insensitivity syndrome patients: a series study of 30 cases from a Chinese tertiary medical center

OBJECTIVE

To study the clinical characteristics and genetic basis of complete androgen insensitivity syndrome (CAIS) in patients from the People's Republic of China. CAIS patients with 46 XY karyotype produce male levels of androgens but present with female external genitalia and secondary sex characteristics. The majority of affected individuals have androgen receptor (AR) gene mutations. This case series explored clinical and molecular characteristics of CAIS patients from the People's Republic of China.

DESIGN

Genomic DNA from peripheral blood of clinically diagnosed CAIS patients was sequenced for mutation in the androgen receptor (AR) gene and steroid 5α-reductase type 2 gene (SRD5A2).

SETTING

Participants were recruited from Peking Union Medical College Hospital when they came in for consultation.

PATIENTS

Thirty patients from unrelated families were recruited.

INTERVENTIONS

Data from medical documents recording diagnosis and treatment of these patients were retrospectively collected.

MAIN OUTCOME MEASURES

Patient genotypes were determined by sequencing the AR and SRD5A2 genes. Their clinical characteristics were summarized based on symptoms, hormone profiles, operative findings, and pathological results.

RESULTS

Twenty-one patients diagnosed with CAIS had mutations in AR exons. Analysis of AR exons revealed the presence of seven novel mutations (c.58C>T, c.645_652delGGGGGCTC, c.910G>T, c.1078C>T, c.1786T>A, c.2230G>T, and c.2522G>C); of these mutations, 47.6% (10/21) were located in the ligand-binding domain. Gonadal insufficiency was found in one case of CAIS. Among the remaining nine patients, three had SRD5A2 mutations and therefore a steroid 5α-reductase deficiency. No AR or SRD5A2 mutations were detected in the other six patients.

CONCLUSION

This study broadens the spectrum of known AR gene mutations responsible for CAIS, and implies that there can be more complex underlying causes of CAIS.

Analysis of variants in GATA4 and FOG2/ZFPM2 demonstrates benign contribution to 46,XY disorders of sex development

Background

GATA‐binding protein 4 (GATA4) and Friend of GATA 2 protein (FOG2, also known as ZFPM2) form a heterodimer complex that has been shown to influence transcription of genes in a number of developmental systems. Recent evidence has also shown these genes play a role in gonadal sexual differentiation in humans. Previously we identified four variants in GATA4 and an unexpectedly large number of variants in ZFPM2 in a cohort of individuals with 46,XY Differences/Disorders of Sex Development (DSD) (Eggers et al, Genome Biology, 2016; 17: 243).

Method

Here, we review variant curation and test the functional activity of GATA4 and ZFPM2 variants. We assess variant transcriptional activity on gonadal specific promoters (Sox9 and AMH) and variant protein–protein interactions.

Results

Our findings support that the majority of GATA4 and ZFPM2 variants we identified are benign in their contribution to 46,XY DSD. Indeed, only one variant, in the conserved N‐terminal zinc finger of GATA4, was considered pathogenic, with functional analysis confirming differences in its ability to regulate Sox9 and AMH and in protein interaction with ZFPM2.

Conclusions

Our study helps define the genetic factors contributing to 46,XY DSD and suggests that the majority of variants we identified in GATA4 and ZFPM2/FOG2 are not causative.

Spermatogenesis disorder is associated with mutations in the ligand-binding domain of an androgen receptor

Androgens play a key role in spermatogenesis, and their functions are mediated by the androgen receptor (AR). Some mutations in the AR gene have the potential to alter the primary structure and function of the protein. The aim of this study was to investigate the AR gene mutations in a cohort of males with idiopathic azoospermia referred to Royan Institute. Fifty-one biopsy samples were obtained for routine clinical purposes from 15 men with hypospermatogenesis (HS), 17 patients with maturation arrest (MA) and 19 patients with Sertoli cell-only syndrome (SCOS). The AR cDNAs were prepared from tissue mRNAs and were sequenced. One synonymous variant and three nonsynonymous protein coding single nucleotide polymorphisms (nsSNPs) were detected. Protein structure prediction demonstrated that the S815I and M746T nonsynonymous variants would affect protein structure and its normal function. Our study suggests that mutations in the AR gene would change or disturb the receptor's normal activity. Although these variations may influence spermatogenesis, it is difficult to say that they lead to a lack of spermatogenesis.