Screening for mutations in 17b-hydroxysteroid dehydrogenase and androgen receptor in women presenting with partially virilised 46,XY disorders of sex development

Abstract

Context and objective: The precise diagnosis of partially virilised women with 46,XY disorders of sex development (DSD) is often obscure. In practice, this group often comes under the poorly defined, clinically based label of partial androgen insensitivity syndrome (PAIS). In a previous study, we found that 5a-reductase 2 (SRD5A2) mutations occurred in 43% of women in this subgroup. We expand this work to include biochemical and genetic screening for 17b-hydroxysteroid dehydrogenase (HSD17B3) and androgen receptor (AR) mutations. Methods: Analysis of serum androgens (androstenedione and testosterone) and genetic analyses for HSD17B3 and AR were performed in 42 women from 36 pedigrees with partially virilised 46,XY DSD in whom SRD5A2 deficiency had been excluded by urine steroid profiling. Results: Out of 36 unrelated women, 14 (38%) were found to have HSD17B3 mutations and one (2.7%) to have an AR defect. Six novel pathogenic HSD17B3 mutations were identified: Three splice site mutations and three missense changes. Seven patients with HSD17B3 deficiency tested before gonadectomy had basal testosterone/androstenedione (T/A) ratio >0.8 (sensitivity 100% and specificity 91%). Conclusions: HSD17B3 deficiency is prevalent in the adolescent and adult 46,XY female DSD population and is often associated with lesser degrees of virilisation compared with those with 5a-reductase deficiency. This diagnosis should be considered for individuals labelled as PAIS, particularly, but not exclusively, those who present with virilisation at puberty or primary amenorrhoea. Before gondadectomy, T/A ratio is useful to aid diagnosis, but after gonadectomy sequencing of HSD17B3 must be performed to confirm the diagnosis.