A novel de novo androgen receptor nonsense mutation in a sex-reversed 46,XY infant

Characterization of a novel androgen receptor gene variant identified in an Iranian family with complete androgen insensitivity syndrome (CAIS): a molecular dynamics simulation study

Androgen insensitivity syndrome (AIS) is a common form of 46, XY disorder in sex development disease (DSD). It is due to the androgen receptor (AR) gene mutations and includes clinical subgroups of complete AIS (CAIS) and partial AIS (PAIS), along with a vast area of clinical heterogeneity of completely normal female external genitalia to male infertility. In this study, the Whole Exome Sequencing (WES) was utilized to detect the cause of DSD in a consanguineous Iranian family with two female patients with normal external genitalia and 46, XY karyotype. Sanger sequencing was applied to validate the candidate variant. Next, we predicted the structural alteration induced by the variant on AR protein using bioinformatics analysis such as molecular dynamic (MD) and molecular docking simulations. WES results identified a novel hemizygous p.L763V variant in the AR gene in the proband that was compatible with the X-linked recessive pattern of inheritance. Bioinformatics studies confirmed the loss of AR function. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, it was categorized as pathogenic. This study broadens the AR mutation spectrum and introduces the novel p.L763V missense pathogenic variant leading to AR failure to bind to its ligand, and the resulting CAIS clinical subgroup. This study presents a prosperous application of WES and bioinformatics analysis to recognize the underlying cause of DSD in Iran, necessary for its clinical/psychological management.Communicated by Ramaswamy H. Sarma.

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.

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.