Prevalence of gene mutations in a Chinese 46,XY disorders of sex development cohort detected by targeted next-generation sequencing

46,XY disorders of sex development(DSD)is characterized by incomplete masculinization genitalia,with gonadal dysplasia and with/without the presence of Mullerian structures.At least 30 genes related to 46,XY DSD have been found.However,the clinical phenotypes of patients with different gene mutations overlap,and accurate diagnosis relies on gene sequencing technology.Therefore,this study aims to determine the prevalence of pathogenic mutations in a Chinese cohort with 46,XY DSD by the targeted nextgeneration sequencing(NGS)technology.Eighty-seven 46,XY DSD patients were enrolled from the Peking Union Medical College Hospital(Beijing,China).A total of fifty-four rare variants were identified in 60 patients with 46,XY DSD.The incidence of these rare variants was approximately 69.0%(60/87).Twenty-five novel variants and 29 reported variants were identified.Based on the American College of Medical Genetics and Genomics(ACMG)guidelines,thirty-three variants were classified as pathogenic or likely pathogenic variants and 21 variants were assessed as variants of uncertain significance.The overall diagnostic rate was about 42.5%based on the pathogenic and likely pathogenic variants.Androgen receptor{AR),steroid 5-alpha-reductase 2(SRD5A2)and nuclear receptor subfamily 5 Group A member 1(NR5A1)gene variants were identified in 21,13 and 13 patients,respectively.The incidence of these three gene variants was about 78.3%(47/60)in patients with rare variants.It is concluded that targeted NGS is an effective method to detect pathogenic mutations in 46,XY DSD patients and AR,SRD5A2,and NR5A1 genes were the most common pathogenic genes in our cohort.

Complete androgen insensitivity syndrome caused by the c.2678C>T mutation in the androgen receptor gene:A case report

BACKGROUND Androgen insensitivity syndrome is an X-linked recessive genetic disease caused by mutations in the androgen receptor gene(AR).However,the underlying molecular mechanisms for the majority of AR variants remain unclear.In this study,we identified a point variant in three patients with complete androgen insensitivity syndrome(CAIS),summarized the correlation analysis,and performed a literature review.CASE SUMMARY The proband was raised as a girl.In infancy,she was first referred to hospital with a right inguinal hernia.Ultrasonography revealed the absence of a uterus and ovaries,and a testis-like structure located at the inguinal canal.Further diagnostic workup detected a 46,XY karyotype,and fluorescence in situ hybridization analysis showed the presence of the SRY gene.Histological analysis revealed the excised tissue to be testicular.Twelve years later,she was admitted to our hospital with a lack of breast development.Her pubic hair and breasts were Tanner stage I.She had normal female external genitalia.Blood hormone tests showed normal testosterone levels,low estradiol levels,and high gonadotropin levels.Her two siblings underwent similar examinations,and all three had a rare hemizygous missense mutation in AR:c.2678C>T.In vitro functional analyses revealed decreased nuclear translocation in AR-c.2678C>T mutation cells.CONCLUSION This case of CAIS was caused by an AR variant(c.2678C>T).Functional studies showed impaired nuclear translocation ability of the mutant protein.