title: Embryonic Testicular Regression Syndrome Presenting as Primary Amenorrhea: A Case Report and Review of Disorders of Sexual Development.
abstract: BACKGROUND
  Sex development depends on the synchronous interaction of complicated genetic and hormonal events. Sex differentiation begins with sex determination, which is the assignment of the embryonic bipotential gonads as either testes or ovaries on the basis of transcriptional regulation. Hormonal regulation then directs the development of the male or female phenotype. Disruptions of this intricate cascade of events result in disorders of sexual development.
  
  
  METHODS
  A 16-year-old female adolescent presented with primary amenorrhea. Evaluation revealed female external genitalia, XY karyotype, absent gonadal tissue, and rudimentary Müllerian structures. On the basis of her constellation of findings, the most logical diagnosis was the rare embryonic testicular regression syndrome.
  
  
  CONCLUSIONS
  A careful understanding of embryonic sexual development is critical to the evaluation of patients with disorders of sexual development.
authors.affiliation: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Electronic address: jdhunter@unch.unc.edu.
authors.forename: J D
authors.initials: JD
authors.lastname: Hunter
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: S R
authors.initials: SR
authors.lastname: Pierce
authors.affiliation: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: A S
authors.initials: AS
authors.lastname: Calikoglu
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: J O
authors.initials: JO
authors.lastname: Howell
mesh_terms: D000293:Adolescent; D000568:Amenorrhea / Q000209:etiology*; D005260:Female; D005836:Genitalia, Female / Q000002:abnormalities; D006061:Gonadal Dysgenesis, 46,XY / Q000150:complications*; D006801:Humans; D013737:Testis / Q000002:abnormalities*
keywords: Amenorrhea; Hypergonadotropic hypogonadism; Testicular regression syndrome