[A Case of 46,XY pure gonadal dysgenesis with loss of the sex-determining region of Y chromosome]

[Pure 46,XY gonadal dysgenesis]

The authors report a rare case of pure 46,XY gonadal dysgenesis (Swyer syndrome). Swyer syndrome is associated with 46,XY karyotype, primary amenorrhea as well as the presence of female internal genital tract and bilateral streak gonads in a phenotypic female. The genetic background of this syndrome includes mutations of several genes involved in the testis differentiation cascade. Mutation of the SRY gene accounts for only 10-15% of all 46,XY gonadal dysgenesis cases while the majority cases may be linked to other deficient genes involved in the sex differentiation pathway. The patient was a 16-year-old female who was referred for endocrinological evaluation because of primary amenorrhea. Physical examination revealed a phenotypic female, height 166 cm, weight: 56.5 kg, breast and pubic hair development were Tanner I. and II, respectively. She had female external genitalia. Pelvic magnetic resonance imaging showed a hypoplastic uterus and ovaries at both sides measuring 5×10 mm in size. Chromosomal analysis revealed 46,XY karyotype. Analysis of the SRY and SF1 genes showed no mutations. Serum follicle-stimulating hormone and luteinizing hormone were elevated. Serum tumor marker concentrations were normal. Prophylactic bilateral gonadectomy was performed and histological examination showed bilateral streak gonads. Hormone replacement therapy produced development of secondary sexual characters and 1.5 years after treatment the patient had menarche. Authors conclude that karyotype analysis should be performed in adolescent with primary amenorrhea. After establishment of the diagnosis, dysgenetic gonads should be removed because of the high risk of gonadal neoplasia.