Supplementary Material for: LRH-1 May Rescue SF-1 Deficiency for Steroidogenesis: An in vitro<b> </b>and in vivo<b> </b>Study

Steroidogenic factor 1 (<i>NR5A1</i>/SF-1) mutations usually manifest in 46,XY individuals with variable degrees of disordered sex development and in 46,XX women with ovarian insufficiency. So far, there is no genotype-phenotype correlation. The broad spectrum of phenotype with <i>NR5A1</i> mutations may be due to a second hit in a gene with similar function to <i>NR5A1</i>/SF-1. Liver receptor homologue-1 (LRH-1/<i>NR5A2</i>) might be a good candidate. We performed in vitro studies for the interplay between SF-1, LRH-1 and DAX-1, expression profiles in human steroidogenic tissues, and <i>NR5A2 </i>genetic studies in a cohort (11 patients, 8 relatives, 11 families) harboring heterozygote <i>NR5A1</i>/SF-1 mutations. LRH-1 isoforms transactivate the <i>CYP17A1 </i>and <i>HSD3B2</i> promoters similarly to SF-1 and compensate for SF-1 deficiency. DAX-1 inhibits SF-1- and LRH-1-mediated transactivation. LRH-1 is found expressed in human adult and fetal adrenals and testes. However, no <i>NR5A2</i>/LRH-1 mutations were detected in 14 individuals with heterozygote <i>NR5A1</i>/SF-1 mutations. These findings demonstrate that in vitro LRH-1 can act like SF-1 and compensate for its deficiency. Expression of LRH-1 in fetal testis suggests a role in male gonadal development. However, as we found no <i>NR5A2</i>/LRH-1 mutations, the ‘second genetic hit' in SF-1 patients explaining the broad phenotypic variability remains elusive.