Editing Disorders of Sexual Differentiation (section)

==== Embryonic Testicular Regression and Bilateral Vanishing Testes Syndromes ====
* '''Karyotype: 46XY'''
* '''Two seperate syndromes characterized by bilateral absent testes in whom there is clear evidence of testicular function at some point during embryogenesis'''
** Distinguished from 46,XY pure gonadal dysgenesis, in which there is no evidence of testicular function in utero
** Embryonic testicular regression refers to loss of testicular tissue within the first trimester and is associated with ambiguity of external genitalia
** Bilateral vanishing testes syndrome refers to individuals in whom male sexual differentiation of ducts and genitalia took place but regression of testicular tissue occurred subsequently in utero.
** Regression of the testes in utero is caused by a genetic mutation, a teratogen, or bilateral torsion
** '''Clinically, these two syndromes represent a spectrum of phenotypes ranging in severity from complete female, to varying degrees of genital ambiguity in the embryonic testicular regression syndrome, to a normal male phenotype with microphallus and empty scrotum in the bilateral vanishing testes syndrome.'''
* '''The diagnosis can be made on the basis of a 46,XY karyotype, castrate levels of testosterone, elevated serum LH and FSH, and undetectable MIS level'''
* Management
** Dictated by clinical spectrum of either disorder