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46,XY difference of sex development due to isolated 17,20-lyase deficiency

Disease definition

A rare difference of sex development due to reduced 17,20-lyase activity that affects individuals with 46,XY karyotype and is characterized by female or atypical external genitalia with reduced phallic size, hypospadias, incomplete fusion of the labioscrotal swellings, cryptorchidism, and a blind vaginal pouch. Blood pressure and electrolytes are normal whilst hormonal investigations show normal basal and stimulated levels of cortisol, and low basal and stimulated androgen levels.


Classification level: Disorder
  • Synonym(s):
    • 46,XY disorder of sex development due to isolated 17,20-lyase deficiency
  • Prevalence: <1 / 1 000 000
  • Inheritance: Autosomal recessive 
  • Age of onset: Neonatal
  • ICD-10: E29.1
  • ICD-11: LD2A.3
  • OMIM: 202110
  • UMLS: C5681470
  • MeSH: -
  • GARD: -
  • MedDRA: -
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