Context: Steroidogenic factor 1 (SF1/AdBP4/FTZF1, NR5A1) is a nuclear receptor transcription factor that plays a key role in regulating adrenal and gonadal development, steroidogenesis, and reproduction. Targeted deletion of Nr5a1 (Sf1) in the mouse results in adrenal and gonadal agenesis, XY sex-reversal, and persistent Müllerian structures in males. Consistent with the murine phenotype, human mutations in SF1 were described initially in two 46,XY individuals with female external genitalia, Müllerian structures (uterus), and primary adrenal failure. Objective: Given recent case reports of haploinsufficiency of SF1 affecting testicular function in humans, we aimed to identify SF1 mutations in a cohort of individuals with a phenotypic spectrum of 46,XY gonadal dysgenesis/impaired androgenization (now termed 46,XY disorders of sex development) with normal adrenal function. Methods and Patients: The study included mutational analysis of NR5A1 in 30 individuals with 46,XY disorders of sex development, followed by functional studies of SF1 activity. Results: Heterozygous missense mutations in NR5A1 were found in four individuals (four of 30, 13%) with this phenotype. These mutations (V15M, M78I, G91S, L437Q) were shown to impair transcriptional activation through abnormal DNA binding (V15M, M78I, G91S), altered subnuclear localization (V15M, M78I), or disruption of the putative ligand-binding pocket (L437Q). Two mutations appeared to be de novo or germline changes. The other two mutations appeared to be inherited in a sex-limited dominant manner because the mother is heterozygous for the change. Conclusions: These studies demonstrate that SF1 mutations are more frequent than previously suspected causes of impaired fetal and postnatal testicular function in 46,XY individuals.

In 46,XY disorders of sex development, 5α-reductase deficiency is rare and is not usually the first-intention diagnosis in newborn ambiguous genitalia, contrary to partial androgen insensitivity syndrome. Yet the cause of ambiguous genitalia may guide sex assignment, and rapid, precise diagnosis of 5α-reductase deficiency is essential. The aim of the study was to describe relevant data for clinical diagnosis, biological investigation, and molecular determination from 55 patients with srd5A2 mutations identified in our laboratory over 20 yr to improve early diagnosis. The study was performed at Montpellier University Hospital. We studied a cohort of 55 patients with srd5A2 gene mutations. Genetic analysis of srd5A2 was conducted. Clitoromegaly (49.1%) and microphallus with various degrees of hypospadias (32.7%) were frequent phenotypes. Female external genitalia (7.3%) and isolated micropenis (3.6%) were rare. Seventy-two percent of patients were initially assigned to female gender; five of them (12.5%) switched to male sex in peripuberty. Over 72% of patients were considered for 5α-reductase deficiency diagnosis when the testosterone/dihydrotestosterone cutoff was 10. In 55 patients (with 20 having a history of consanguinity), we identified 33 different mutations. Five have never been reported: p.G32S, p.Y91H, p.G104E, p.F223S, and c.461delT. Homozygous mutations were present in 69.1% of cases, compound heterozygous mutations in 25.5%, and compound heterozygous mutations alone with the V89L polymorphism in 5.4%. Exons 1 and 4 were most affected, with 35.8 and 21.7% mutant alleles per exon, respectively. In the largest cohort to date, we demonstrate a wide spectrum of phenotypes and biological profiles in patients with 5α-reductase deficiency, whatever their geographical or ethnic origins.

Context: Müllerian duct development depends on gene and hormone interactions. Female Wnt4-knockout mice lack müllerian ducts and are virilized due to the inappropriate expression of the enzymes required for androgen production (normally repressed in female ovary). The WNT4 mutation was recently reported to be associated with failure of müllerian duct formation and virilization in two 46, XX women. Objectives: This collaborative work was designed to determine whether the WNT4 mutation could be identified in a group of adolescent girls with Mayer-Rokitansky-Küster-Hauser syndrome. Results: We analyzed 28 DNA samples from adolescent girls with primary amenorrhea and failure of müllerian duct formation by direct sequencing and identified a new L12P mutation within exon 1 of the WNT4 gene. The substitution of leucine by proline is crucial for the conformation of the expressed protein. This amino acid substitution is unlikely to be a polymorphism because it was not found in 100 DNAs from control subjects. Functional analysis revealed that the mutation induces significantly increased expression of the enzymes involved in androgen biosynthesis (3β-hydroxysteroid dehydrogenase and 17α-hydroxylase). It is interesting to note that the adolescent carrying the mutation was referred to our clinic for primary amenorrhea and hyperandrogenism (severe acne and plasma testosterone: 1.8 vs. 1.2 nmol/liter in controls). She also presented with uterine hypoplasia and follicle depletion. Conclusions: We suggest that in adolescent girls with primary amenorrhea, müllerian duct abnormalities, and hyperandrogenism, a WNT4 mutation should be sought. Moreover, our data confirm that WNT4 is involved in the regulation of müllerian duct development and ovarian androgen biosynthesis. WNT4 may also contribute to human follicle development and/or maintenance.

Mayer–Rokitansky–Kuster–Hauser (MRKH) syndrome is characterized by Müllerian duct aplasia in an XX individual with female phenotype presenting primary amenorrhea at adolescence. Multiple abnormalities may be associated with the MRKH syndrome. Genetic investigations focused on the genes of anti-Müllerian hormone and its receptor, as well as on Wt1, Pax2, Cftr and Hox genes, have been unproductive. Only the Wnt4 gene has been clearly implicated in MRKH syndrome and found to be associated with clinical and/or biological signs of hyperandrogenism in three different works. Beside the multiple malformations that may be associated with MRKH syndrome, such as renal, skeletal, cardiac and auditory defects, MRKH and hyperandrogenism represent a new clinical and genetic disorder.

Steroidogenic factor 1 (SF1/AdBP4/FTZF1, NR5A1 ) is a nuclear receptor transcription factor that plays a key role in regulating adrenal and gonadal development, steroidogenesis and reproduction. Recently, haploinsufficiency of SF1 has been described in several 46,XY individuals with mild gonadal dysgenesis and impaired androgenization, but normal adrenal function, suggesting that dosage-sensitive or domain-specific effects of SF1 action are important in human testicular development and function. Our objective was to investigate whether partial defects in SF1 function might be associated with milder male reproductive phenotypes, such as bilateral anorchia (‘vanishing testis syndrome’) and micropenis. This study involved mutational analysis of NR5A1 in 24 individuals with bilateral anorchia and micropenis from the French Collaborative Anorchia study, as well as in vitro functional studies of SF1-dependent transcriptional activation and computer modeling. A novel heterozygous missense mutation (V355M) in SF1 was found in one boy with a micropenis and testicular regression syndrome. This non-synonymous change was found to affect a highly conserved amino acid within helix 7 of the ligand-binding domain of SF1. This V355M mutation did not affect stability or nuclear localization, but did result in an ∼50% reduction in SF1 activity in several different assay systems. In conclusion, heterozygous partial loss of function mutations in SF1 may be associated with bilateral anorchia (‘vanishing testis syndrome’) and micropenis in humans.