[Clinical characteristics and genetic analysis of a case with 47,XYY Disorder of sex development due to variant of NR5A1 gene].

Objective: To investigate the clinical phenotype and genetic etiology of a patient with tall stature and primary amenorrhea presenting with 47,XYY Disorder of sex development (DSD).

Methods: A female patient presenting with "tall stature and primary amenorrhea" at Nanjing Drum Tower Hospital in July 2024 was selected as the study subject. A retrospective study design was employed to collect the patient's clinical data. Peripheral venous blood sample was collected. Following the extraction of genomic DNA, genetic testing was performed including chromosomal karyotyping analysis, copy number variation sequencing (CNV-seq), multiplex PCR for the AZF regions and sex-determining genes Y (SRY), and whole-exome sequencing (WES). Candidate variants were validated by Sanger sequencing and classified for pathogenicity based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of Nanjing Drum Tower Hospital (Ethics No.: 2022-451-01).

Results: The patient had a height of 188 cm and a body weight of 50 kg, in addition with infantile uterus, absent ovaries, and primary amenorrhea. G-banded karyotyping analysis of peripheral blood sample revealed 47,XYY. CNV-seq indicated Seq[GRCh37]Yp11.32q12×2. No deletion was detected in the AZF regions of Y chromosome, and SRY was positive. WES identified a heterozygous c.86C>A (p.Thr29Lys) variant of the NR5A1 gene, leading to substitution of threonine with lysine at position 29 of the encoded protein. Sanger sequencing confirmed the presence of the variant. According to the ACMG guidelines, this variant was classified as variant of uncertain significance (VUS) with supporting evidence (PS3_Moderate+PM5+PP3+PM2_Supporting+PS4_Supporting). Reviewing the nearly 60 years of previously reported cases, all 7 documented 47,XYY DSD patients were assigned a female social gender and presented with abnormal gonadal and external genitalia development. Among them, 5 cases underwent SRY testing, all of which were positive. Only 1 case underwent whole-exome sequencing (WES), but no pathogenic or likely pathogenic variants were identified.

Conclusion: This DSD patient presented with the clinical features of tall stature and primary amenorrhea. The NR5A1 gene variant c.86C>A (p.Thr29Lys) probably underlay the Disorder of sex development in this patient. Above finding has enriched the spectrum of pathogenic variants of the NR5A1 gene.