46,XY disorder of sex development due to 17-beta hydroxysteroid dehydrogenase type 3 deficiency: a plea for timely genetic testing.
BACKGROUND
17β-hydroxysteroid dehydrogenase type 3 (17βHSD3) deficiency is a rare cause of disorder of sex development (DSD) due to impaired conversion of androstenedione to testosterone. Traditionally, the diagnosis was determined by βHCG-stimulated ratios of testosterone:androstenedione < 0.8.


METHODS
An otherwise phenotypically female infant presented with bilateral inguinal masses and a 46,XY karyotype. βHCG stimulation (1500 IU IM for 2 days) suggested 17βHSD3 deficiency although androstenedione was only minimally stimulated (4.5 nmol/L to 5.4 nmol/L). Expedient genetic testing for the HSD17B3 gene provided the unequivocal diagnosis.


CONCLUSIONS
We advocate for urgent genetic testing in rare causes of DSD as indeterminate hormone results can delay diagnosis and prolong intervention.
Division of Endocrinology, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy, 11405- 87th Ave., Edmonton, AB T6G 1C9 Canada.
Chelsey
C
Grimbly
Department of Medical Genetics, University of Alberta, 8-39 Medical Sciences Building, 8613 114 St., Edmonton, AB T6G 2H7 Canada.
Oana
O
Caluseriu
Division of Pediatric Urology, Department of Pediatric Surgery, University of Alberta, 2C3.79 WC Mackenzie Health Sciences Centre, Edmonton, AB T6G 2R7 Canada.
Peter
P
Metcalfe
Division of Endocrinology, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy, 11405- 87th Ave., Edmonton, AB T6G 1C9 Canada.
Mary M
MM
Jetha
Division of Endocrinology, Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy, 11405- 87th Ave., Edmonton, AB T6G 1C9 Canada.
Elizabeth T
ET
Rosolowsky
17β-hydroxysteroid dehydrogenase type 3 deficiency; 46,XY undervirilization; Disorders of sex development