Mutational analysis of the androgen receptor (NR3C4) gene in patients with 46,XY DSD

Molecular and Cytogenetic Analysis of Romanian Patients with Differences in Sex Development

Differences in sex development (DSD) are often correlated with a genetic etiology. This study aimed to assess the etiology of DSD patients following a protocol of genetic testing. Materials and methods. This study prospectively investigated a total of 267 patients with DSD who presented to Clinical Emergency Hospital for Children Cluj-Napoca between January 2012 and December 2019. Each patient was clinically, biochemically, and morphologically evaluated. As a first intervention, the genetic test included karyotype + SRY testing. A high value of 17-hydroxyprogesterone was found in 39 patients, in whom strip assay analysis of the CYP21A2 gene was subsequently performed. A total of 35 patients were evaluated by chromosomal microarray technique, and 22 patients were evaluated by the NGS of a gene panel. Results. The karyotype analysis established the diagnosis in 15% of the patients, most of whom presented with sex chromosome abnormalities. Genetic testing of CYP21A2 established a confirmation of the diagnosis in 44% of patients tested. SNP array analysis was particularly useful in patients with syndromic DSD; 20% of patients tested presented with pathogenic CNVs or uniparental disomy. Gene panel sequencing established the diagnosis in 11 of the 22 tested patients (50%), and the androgen receptor gene was most often involved in these patients. The genes that presented as pathogenic or likely pathogenic variants or variants of uncertain significance were RSPO1, FGFR1, WT1, CHD7, AR, NIPBL, AMHR2, AR, EMX2, CYP17A1, NR0B1, GNRHR, GATA4, and ATM genes. Conclusion. An evaluation following a genetic testing protocol that included karyotype and SRY gene testing, CYP21A2 analysis, chromosomal analysis by microarray, and high-throughput sequencing were useful in establishing the diagnosis, with a spectrum of diagnostic yield depending on the technique (between 15 and 50%). Additionally, new genetic variants not previously described in DSD were observed.

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.

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.

Late-onset vanishing testis-like syndrome in a 38,XX/38,XY agonadic pig (Sus scrofa)

Here we describe the case of a pig with intersex traits including ambiguous external genitalia, sex chromosome abnormalities and a late-onset vanishing testis-like syndrome. It was identified shortly after birth by presenting a predominantly female phenotype with two large scrotal masses resembling testes. The karyotype is 38,XX (53%)/38,XY (47%). Sex steroid levels were undetectable at 1 and 7 months old, whereas circulating cortisol levels were typical. DNA studies excluded gene alterations in sex-determining region Y (SRY), dosage-sensitive sex reversal-congenital adrenal hypoplasia critical region on the X chromosome protein 1 (DAX1), SRY-related high mobility group-box gene 9 (SOX9), nuclear receptor subfamily 5, group a, member 1 (NR5A1), nuclear receptor subfamily 3, group c, member 4 (NR3C4) and steroid 5-alpha-reductase 2 (SRD5A2). At 8 months of age the XX/XY pig evinced delayed growth; however, the most striking phenotypic change was that the testes-like structures completely vanished in a 2-3-week period. The internal genitalia were found to consist of a portion of a vagina and urethra. No fallopian tubes, uterus or remnants of Wolffian derivatives were observed. More importantly, no testes, ovaries, ovotestis or gonadal streaks could be identified. The XX/XY sex chromosome dosage and/or overexpression of the DAX1 gene on the X chromosome in the presence of a wild-type SRY gene may have caused this predominantly female phenotype. This specimen represents an atypical case of 38,XX/38,XY chimeric, ovotesticular disorder of sex development associated with agonadism.

Novel Mutations Segregating with Complete Androgen Insensitivity Syndrome and their Molecular Characteristics

We analyzed three cases of Complete Androgen Insensitivity Syndrome (CAIS) and report three hitherto undisclosed causes of the disease. RNA-Seq, Real-timePCR, Western immunoblotting, and immunohistochemistry were performed with the aim of characterizing the disease-causing variants. In case No.1, we have identified a novel androgen receptor (AR) mutation (c.840delT) within the first exon in the N-terminal transactivation domain. This thymine deletion resulted in a frameshift and thus introduced a premature stop codon at amino acid 282. In case No.2, we observed a nonsynonymous mutation in the ligand-binding domain (c.2491C>T). Case No.3 did not reveal AR mutation; however, we have found a heterozygous mutation in CYP11A1 gene, which has a role in steroid hormone biosynthesis. Comparative RNA-Seq analysis of CAIS and control revealed 4293 significantly deregulated genes. In patients with CAIS, we observed a significant increase in the expression levels of PLCXD3, TM4SF18, CFI, GPX8, and SFRP4, and a significant decrease in the expression of SPATA16, TSACC, TCP10L, and DPY19L2 genes (more than 10-fold, p < 0.05). Our findings will be helpful in molecular diagnostics of patients with CAIS, as well as the identified genes could be also potential biomarkers for the germ cells differentiation process.