Malformation syndromes associated with disorders of sex development.

[alpha-thalassemia]

When embryological development of the internal and /or external genitalia is disrupted , the patient presents with a disorder of sex development (DSD ) in the neonatal period or sometime later in life . Some of these patients have other , nongenital malformations , which makes their overall management more complex than if they just had a DSD . This Review summarises these malformation syndromes and discusses the recent research into their aetiology . The genetic causes of these malformation syndromes , when they are known , will also be described . Many specific genetic mutations are now known in malformation syndromes with a defect in hormonal function . By contrast , the genetic causes remain unknown in many nonhormonal morphological anomalies that affect the genitalia .