Disorders of Sex Development

Abstract

The term disorders in sexual differentiation (DSD) to designate all intersex disorders was introduced in the consensus classification of intersex disorders emanating from the Chicago Meeting in 2005 [1]. This classification considers the use of some terms, such as pseudohermaphroditism, hermaphroditism, sex reversal, and intersex situation, obsolete; however, it has given rise to many critical comments [2] because it was made on the basis of chromosomal constitution (peripheral karyotype of leukocytes). Specifically, in cases of gonadal dysgenesis, entities with a completely different histopathology, such as 45,X0 Turner’s syndrome and its variants and mixed gonadal dysgenesis (45,X0/45,XY), have been included with Klinefelter’s syndrome and its variants under the term disorders in sex development. On the other hand, other entities with a similar histopathology, such as 46,XY gonadal dysgenesis and 46,XX gonadal dysgenesis, have been classified into different groups. Two facts have prevented a solution to the problem in classifying these disorders: (1) the same karyotype may produce different phenotypes; and (2) it has been progressively understood that gonadal dysgenesis, instead of showing one cellular line, has mosaicisms or more complex chromosomal constitutions. Therefore, the classification of these disorders considering different viewpoints, including genetic, endocrinologic, clinical, and histopathologic, has not yet been resolved.