ESPE Abstracts

Background: 17β-Hydroxysteroid dehyrogenase type 3 (17βHSD-3) deficiency is an autosomal recessive form of 46,XY disorder of sex development (DSD). 17βHSD-3 is present almost exclusively in the testes and converts androstenedione to testosterone. The diagnosis can be easily missed in early childhood as the clinical presentation may be subtle. The most frequent presentation of 17βHSD-3 deficiency is a 46,XY individual with female external genitalia, labial fusion and a blind ending vagina, with or without clitoromegaly. In these patients, the diagnosis may be missed until adolescence. At the time of puberty, patients present with primary amenorrhea, varying degrees of virilization including development of male body habitus, increased body hair and deepening of the voice. A low T/A ratio on baseline or human chorionic gonadotropin stimulated testing is suggestive of 17βHSD-3 deficiency. The diagnosis can be confirmed with molecular genetic studies.

Objective and hypotheses: 17βHSD-3 deficiency, a rare cause of 46,XY sexual development disorder can be diagnosed with a careful physical examination.

Method: A 12-day patient was referred to our hospital because of palpabl gonad in labia majora. On physical examination, she has female external genitalia, without clitoromegaly. The karyotype was 46,XY.

Results: T/A ratio was 0,128 and diagnosed 17βHSD-3 deficiency. We detected compound heterozygous novel frameshift mutations in exon 9 and 10 of HSD17B3 gene.

Conclusion: The external genitalia of our case was totally female in appearance, but it was the first case that could be diagnosed in the newborn period as a gonad was seen in the labium major. The patient is now 1.5 years old and the decision regarding final gender will be made eventually.