DMRT1 is a testis-determining gene in rabbits and is also essential for female fertility.

DMRT1 is the testis-determining factor in several species of vertebrates, but its involvement in mammalian testes differentiation, where SRY is the testis-determining gene, remains ambiguous. So far, DMRT1 loss-of-function has been described in two mammalian species and induces different phenotypes: Disorders of Sex Development (46, XY DSD) in men and male infertility in mice. We thus abolished DMRT1 expression by CRISPR/Cas9 in a third species of mammal, the rabbit. First, we observed that gonads from XY DMRT1-/- rabbit fetuses differentiated like ovaries, highlighting that DMRT1 is involved in testis determination. In addition to SRY, DMRT1 is required in the supporting cells to increase the expression of the SOX9 gene, which heads the testicular genetic cascade. Second, we highlighted another function of DMRT1 in the germline since XX and XY DMRT1-/- ovaries did not undergo meiosis and folliculogenesis. XX DMRT1-/- adult females were sterile, showing that DMRT1 is also crucial for female fertility. To conclude, these phenotypes indicate an evolutionary continuum between non-mammalian vertebrates such as birds and non-rodent mammals. Furthermore, our data support the potential involvement of DMRT1 mutations in different human pathologies, such as 46, XY DSD as well as male and female infertility.

Animals that reproduce sexually have organs called gonads, the ovaries and testes, which produce eggs and sperm. These organs, which are different in males and females, originate from the same cells during the development of the embryo. As a general rule, the chromosomal sex of an embryo, which gets determined at fertilization, leads to the activation and repression of specific genes. This in turn, controls whether the cells that will form the gonads will differentiate to develop testes or ovaries. Disruption of the key genes involved in the differentiation of the gonads can lead to fertility problems, and in some cases, it can cause the gonads to develop in the 'opposite' direction, resulting in a sex reversal. Identifying these genes is therefore essential to know how to maintain or restore fertility. DMRT1 is a gene that drives the differentiation of gonadal cells into the testicular pathway in several species of animals with backbones, including species of fish, frogs and birds. However, its role in mammals ­ where testis differentiation is driven by a different gene called SRY ­ is not well understood. Indeed, when DMRT1 is disrupted in male humans it leads to disorders of sex development, while disrupting this gene in male mice causes infertility. To obtain more information about the roles of DMRT1 in mammalian species, Dujardin et al. disrupted the gene in a third species of mammal: the rabbit. Dujardin et al. observed that chromosomally-male rabbits lacking DMRT1 developed ovaries instead of testes, showing that in rabbits, both SRY and DMRT1 are both required to produce testes. Additionally, this effect is similar to what is seen in humans, suggesting that rabbits may be a better model for human gonadal differentiation than mice are. Additionally, Dujardin et al. were also able to show that in female rabbits, lack of DMRT1 led to infertility, an effect that had not been previously described in other species. The results of Dujardin et al. may lead to better models for gonadal development in humans, involving DMRT1 in the differentiation of testes. Interestingly, they also suggest the possibility that mutations in this gene may be responsible for some cases of infertility in women. Overall, these findings indicate that DMRT1 is a key fertility gene.

Genetics of anti-Müllerian hormone and its signaling pathway.

Anti-Müllerian hormone (AMH) is a member of the TGF-ß family produced essentially by the supporting somatic cells of the testis. Initially known for its inhibiting role upon the development of female internal organs, AMH has been shown to exert many other effects namely upon germ cells. Circulating AMH reflects the ovarian reserve of young developing follicles and is used to evaluate the fertility potential in assisted reproduction. The signaling pathway of AMH is both similar and different from that of other members of the TGF-ß family. Like these, it signals through two distinct serine/threonine receptors, type 1 and type 2, that phosphorylate cytoplasmic effectors, the Smads. It also shares type 1 receptors and Smads with other members of the family. However, AMH is the only family member with its own, dedicated, ligand-specific type 2 receptor, AMHR2. The monogamic relationship between AMH and AMHR2 is supported by molecular studies of the Persistent Müllerian Duct Syndrome, characterized by the presence of Müllerian derivatives in otherwise normally virilized males: mutations of AMH or AMHR2 are clinically indistinguishable.

Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia.

Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH.

Molecular basis for the recognition of steroidogenic acute regulatory protein by the 14-3-3 protein family.

Steroidogenesis in adrenals and gonads starts from cholesterol transport to mitochondria. This is mediated by the steroidogenic acute regulatory protein (STARD1), containing a mitochondrial import sequence followed by a cholesterol-binding START domain. Although mutations in this protein have been linked to lipoid congenital adrenal hyperplasia (LCAH), the mechanism of steroidogenesis regulation by STARD1 remains debatable. It has been hypothesized to involve a molten-globule structural transition and interaction with 14-3-3 proteins. In this study, we aimed to address the structural basis for the 14-3-3-STARD1 interaction. We show that, while the isolated START domain does not interact with 14-3-3, this interaction is enabled by STARD1 phosphorylation at Ser57, close to the mitochondrial peptide cleavage site. Biochemical analysis of the STARD1 affinity toward 14-3-3 and crystal structures of 14-3-3 complexes with Ser57 and Ser195 phosphopeptides suggest distinct roles of site-specific phosphorylations in recruiting 14-3-3, to modulate STARD1 activity, processing and import to the mitochondria. Phosphorylation at Ser195 creates a unique conditional site that could only bind to 14-3-3 upon partial unfolding of the START domain. Overall, our findings on the interaction between 14-3-3 and STARD1 may have potential clinical implications for patients with LCAH.

Lipoid congenital adrenal hyperplasia due to steroid acute regulatory protein (STAR) variants in Three Chinese patients.

Congenital adrenal hyperplasia (CAH) encompasses a group of autosomal recessive diseases characterized by enzymatic defects in steroid synthesis. Lipoid congenital adrenal hyperplasia (LCAH) is the most severe form of CAH, insofar as the initial step of steroid synthesis is impaired. Variants in the steroid acute regulatory (STAR) gene are responsible for LCAH. To describe the clinical and genetic characteristics of three Chinese patients with LCAH. We analyzed the history, clinical manifestations, physical examination, laboratory data, and computed tomography findings of three girls with LCAH. The STAR gene of the probands and their parents were sequenced using genomic DNA. The wild-type and mutant STAR cDNAs were inserted into the pcDNA3.1(+) plasmid vector and transiently transfected into COS7 cells. The enzymatic activities of the wild-type and mutant STAR were evaluated by the enzyme-dependent conversion efficiency of cholesterol to pregnenolone. We identified the molecular genetic abnormalities in three patients with LCAH. All three patients had a female phenotype: karyotype of patients 1 and 2 was 46, XY and patient 3 was 46, XX. DNA sequencing revealed compound heterozygous variants in STAR for three probands. Two variants, c.659A > G/p.His220Arg and exon 2-3 deletion, were novel. In vitro functional studies uncovered that the His220Arg variant retained 19.2 % of enzymatic activity compared to that of the wild type.

Evaluation of 17ß-hydroxysteroid dehydrogenase activity using androgen receptor-mediated transactivation.

17ß-Hydroxysteroid dehydrogenases (17ß-HSDs) catalyze the reduction of 17-ketosteroids and the oxidation of 17ß-hydroxysteroids to regulate the production of androgens and estrogens. Among them, 17ß-HSD type 3 (HSD17B3) is expressed almost exclusively in testicular Leydig cells and contributes to development of male sexual characteristics by converting androstenedione (A4) to testosterone (T). Mutations of HSD17B3 genes cause a 46,XY disorder of sexual development (46,XY DSD) as a result of low T production. Therefore, the evaluation of 17ß-HSD3 enzymatic activity is important for understanding and diagnosing this disorder. We adapted a method that easily evaluates enzymatic activity of 17ß-HSD3 by quantifying the conversion from A4 to T using androgen receptor (AR)-mediated transactivation. HEK293 cells were transduced to express human HSD17B3, and incubated medium containing A4. Depending on the incubation time with HSD17B3-expressing cells, the culture media progressively increased luciferase activities in CV-1 cells, transfected with the AR expression vector and androgen-responsive reporter. Culture medium from HSD17B1 and HSD17B5-expressing cells also increased the luciferase activities. This system is also applicable to detect the conversion of 11-ketoandrostenedione to 11-ketotestosterone by HSD17B3. Establishment of HEK293 cells expressing various missense mutations in the HSD17B3 gene associated with 46,XY DSD revealed that this system is effective to evaluate the enzymatic activities of mutant proteins.

AMH and AMHR2 mutations: A spectrum of reproductive phenotypes across vertebrate species.

Anti-Müllerian hormone (AMH) is a member of the Transforming Growth Factor-ß family of secreted signaling proteins. AMH is expressed in Sertoli cells of the fetal and adult testes and granulosa cells of the postnatal ovary. AMH is required for the regression of the Müllerian ducts in mammalian fetuses during male differentiation. AMH signals through its Type II receptor, AMHR2. AMHR2 is expressed in mesenchyme adjacent to the Müllerian ducts, and in Sertoli, Leydig, and granulosa cells. Although AMH and AMHR2 genes have been identified in numerous vertebrate species, spontaneous or engineered mutations or variants have been found or created in only a few mammals and teleost fishes. AMH or AMHR2 mutations in mammals lead to the development of Persistent Müllerian Duct Syndrome (PMDS), a recessive condition in which affected males are fully virilized but retain Müllerian duct-derived tissues, including a uterus and oviducts, and in human and dog, undescended testes. Amh mutant female mice had accelerated ovarian primordial follicle recruitment, suggesting a role for AMH in regulating germ cells. amh and amhr2 mutations have also been experimentally generated in various teleost fishes. Depending on the fish species, loss of AMH signaling results in infertility, germ cell tumors, or male-to-female sex reversal. Here we compare the spectrum of phenotypes caused by AMH and AMHR2 mutations in a variety of vertebrate species. There are both common and unique phenotypes between species, highlighting the range of biological processes regulated by AMH signaling.

In Vivo Verification of the Pathophysiology of Lipoid Congenital Adrenal Hyperplasia in the Adrenal Cortex.

A two-hit hypothesis has been proposed to describe the pathophysiology of lipoid congenital adrenal hyperplasia. In previous studies using conventional steroidogenic acute regulatory protein (Star) gene knockout (KO) mice, adrenocortical lipid accumulation was already prominent at birth. Thus, the two-hit hypothesis was verified in the gonads of Star KO mice but not in the adrenal cortices. We generated time-dependent conditional Star KO mice induced by tamoxifen (TAM) injections and analyzed the adrenal cortices of the mice histologically and endocrinologically before, 24 hours after, and 8 weeks after TAM. We performed RNA sequencing analyses of the adrenal glands before and 8 weeks after TAM and histologically analyzed autologous adrenal cortices of TAM-induced Star KO mice with transplantation of wild-type adrenal gland. Lipid accumulation was scattered 24 hours after TAM and was prominent 8 weeks after TAM. Steroidogenic capacity decreased sequentially after TAM. Gene expression related to steroid biosynthesis significantly decreased 8 weeks after TAM compared with that before TAM. TAM-induced Star KO mice with adrenal transplantation showed normal ACTH levels and mild lipid accumulation. These results showed that the steroidogenic capacity decreased without histological change (the first hit) and declined with histological change (the second hit). Thus, we visualized the two-hit hypothesis in the adrenal cortex. The key feature of the secondary decline of steroidogenic capacity might be the decreased gene expression related to steroid biosynthesis after lipid accumulation exacerbated by ACTH hypersecretion.

Childhood Sex-Typed Behavior and Gender Change in Individuals with 46,XY and 46,XX Disorders of Sex Development: An Iranian Multicenter Study.

Disorders of sex development (DSD) are congenital conditions in which the typical genetic and hormonal profiles are affected and thereby the usual process of sexual differentiation. Most of these studies, however, have been conducted in Western countries. In the present study, preschool sex-typed activities of Iranian individuals with DSD and their age-matched non-affected male and female relatives were assessed using the Pre-School Activities Inventory (PSAI) modified for retrospective self-report. A total of 192 individuals participated in our study, including 33 46,XX individuals with congenital adrenal hyperplasia (CAH; M age = 10.36, SD = 5.52), 15 46,XY individuals with complete androgen insensitivity syndrome (CAIS; M age = 19.8, SD = 7.14), and 16 46,XY individuals with 5-alpha reductase deficiency type-2 (5α-RD-2; M age = 17.31, SD = 7.28), as well as one age-matched non-affected male and female relative for each patient. With regard to PSAI scores, male-identifying participants with 5α-RD-2 and male controls reported similar levels of male-typical childhood play. Female-identifying participants with 5α-RD-2 and CAH showed comparable scores: significantly less masculine and more feminine than male controls, but significantly more masculine and less feminine than females with CAIS and female controls. These findings support the role of androgens in the development of sex-typical childhood play behavior, with those being exposed to higher levels of fetal functional androgens expressing more masculine behavior at preschool ages.

Prenatal testosterone and theory of mind development: Findings from disorders of sex development.

Women on average perform better than men on the "Reading the Mind in the Eyes" test (RMET) which is a measure of Theory of Mind (ToM). The aim of this study was to assess whether these sex differences are influenced by differences in prenatal testosterone levels through a study on individuals with Disorders of Sex Development and matched controls. ToM performance was examined using the RMET in female-assigned-at-birth individuals with increased prenatal testosterone exposure (Congenital Adrenal Hyperplasia (CAH) and 5-alpha Reductase type-2 Deficiency (5α-RD-2)), female-assigned-at-birth individuals with testosterone insensitivity (Complete Androgen Insensitivity Syndrome (CAIS)), and their age-matched unaffected male and female relatives. A total number of 158 individuals participated in the study; 19 with 5α-RD-2, 17 with CAH, 18 women with CAIS, 52 matched unaffected men and 52 matched unaffected women. All subgroups were around 20 years of age. Women with CAH scored significantly lower on RMET than control women and CAIS individuals. CAIS individuals scored significantly higher than control men and participants with 5α-RD. Statistically, CAIS individuals' performance on RMET was similar to control women's, women with CAH did not differ significantly from control men and 5α-RD-2 individuals scored significantly lower than control men. These results, which are in line with previous theories, illustrate that performance on the RMET, as an index of ToM, may be influenced by variations in prenatal androgens levels.

46,XY Disorder of Sex Development due to 17-Beta Hydroxysteroid Dehydrogenase Type 3 Deficiency in an Infant of Greek Origin.

17-beta hydroxysteroid dehydrogenase type 3 (17ßHSD-3) enzyme catalyzes the conversion of androstenedione (Δ4) to testosterone (T) in the testes of the developing fetus, thus playing a crucial role in the differentiation of the gonads and in establishing the male sex phenotype. Any mutation in the encoding gene (HSD17B3) can lead to varying degrees of undervirilization of the affected male, ranging from completely undervirilized external female genitalia to predominantly male with micropenis and hypospadias. We present here an infant who was referred to our clinic because of ambiguous genitalia at birth. Gonads were palpable in the inguinal canal bilaterally and no Müllerian structures were identified on pelvic ultrasound. Because of a low T/Δ4 ratio after a human chorionic gonadotropin stimulation test, a tentative diagnosis of 17ßHSD-3 deficiency was made which was confirmed after genetic analysis of the HSD17B3 gene of the patient. The molecular analysis identified compound heterozygosity of two previously described mutations and could offer some further validation for the idea of a founder effect for 655-1;G→A mutation in the Greek population.

Heterogeneity of human WT1 gene.

The WT1 gene, characterized by an extremely complex structure, is located on chromosome 11. It is involved in cell growth and differentiation, and has a strong impact on consecutive stages of the functioning of the body. The WT1 gene may undergo many different mutations, as well as may be overexpressed without a mutation. The molecular basis of diseases such as Wilms tumor, WAGR, Denys-Drash or Frasier syndromes are congenital WT1 mutations, while somatic mutations of this gene occur in acute and chronic myeloid leukemia, myelodysplastic syndrome and also in some other blood neoplasms, as acute lymphoblood leukemia. Increased expression of this gene without its mutation is observed in leukemias and solid tumors. The WT1 may function both as a tumor suppressor gene and as an oncogene. The diversity of WT1 changes causes many controversies, therefore investigations are still carried out to determine the function of this gene, its interaction with other molecules and its prognostic significance in various diseases.

Birth Weight in Different Etiologies of Disorders of Sex Development.

CONTEXT: It is well established that boys are heavier than girls at birth. Although the cause of birth weight (BW) difference is unknown, it has been proposed that it could be generated from prenatal androgen action. OBJECTIVE: The aim of the current study was to determine the BW of children with disorders of sex development (DSD) of different etiologies and to evaluate the effects of androgen action on BW. METHODS: Data regarding diagnosis, BW, gestational age, karyotype, and concomitant conditions were collected from the International Disorders of Sex Development (I-DSD) Registry (www.i-dsd). BW standard deviation score was calculated according to gestational age. Cases were evaluated according to disorder classification in I-DSD (i.e., disorders of gonadal development, androgen excess, androgen synthesis, androgen action, nonspecific disorder of undermasculinization groups, and Leydig cell defect). RESULTS: A total of 533 cases were available; 400 (75%) cases were 46,XY, and 133 (25%) cases were 46,XX. Eighty cases (15%) were born small for gestational age (SGA). Frequency of SGA was higher in the 46,XY group (17.8%) than in the 46,XX (6.7%) group (P = 0.001). Mean BW standard deviation scores of cases with androgen excess and androgen deficiency [in disorders of gonadal development, androgen synthesis, and Leydig cell defect groups and androgen receptor gene (AR) mutation-positive cases in disorders of androgen action groups] were similar to normal children with the same karyotype. SGA birth frequency was higher in the AR mutation-negative cases in disorders of androgen action group and in the nonspecific disorders of the undermasculinization group. CONCLUSIONS: BW dimorphism is unlikely to be explained by fetal androgen action per se. 46,XY DSDs due to nonspecific disorders of undermasculinization are more frequently associated with fetal growth restriction, SGA, and concomitant conditions.

Novel AMH and AMHR2 Mutations in Two Egyptian Families with Persistent Müllerian Duct Syndrome.

Anti-müllerian hormone (AMH) is produced by Sertoli cells and signals through 2 transmembrane receptors (AMHR), specific types I and II, leading to regression of müllerian ducts during fetal male sex differentiation. Mutations in AMH and AMHR2 lead to the persistence of müllerian ducts in males which is transmitted in a recessive pattern. Here, we report 2 Egyptian DSD (disorder of sex development) patients reared as males who presented with bilateral cryptorchidism and otherwise normal male external genitalia and who both had a 46,XY karyotype. The first patient presented at the age of 2 years. Laparoscopic surgery revealed a uterus and fallopian tubes with the presence of 2 gonads, and biopsy and pathology revealed prepubertal testicular tissue showing small-sized tubules with mostly Sertoli cells and very few spermatogonia, edematous stroma, and no detectable ovarian tissue. The second patient presented at the age of 3 years. Laparoscopic surgery revealed a uterus and fallopian tubes, and serum AMH was very low (0.1 ng/mL). Molecular studies revealed a novel missense mutation in the AMHR2 gene in the first patient (c.767A>C; p.H256P) and a novel frameshift mutation in the AMH gene in the second patient (c.203delC; p.L70Cfs*7). We conclude that persistent müllerian ducts should be included in the differential diagnosis of cryptorchidism.

New Territory for an Old Disease: 5-Alpha-Reductase Type 2 Deficiency in Bulgaria.

Disorders/differences of sexual development (DSD) are a group of conditions, some of which can be clinically indistinguishable mainly due to their phenotypic variability. Defining the molecular basis of their wide spectrum is still in progress. The diagnosis of 5-alpha-reductase type 2 (5α-reductase-2) deficiency is difficult especially in newborns and pre-pubertal individuals, and as a result its frequency might be underestimated. In the present study, we describe the clinical characteristics and molecular defects in 3 nonrelated 5α-reductase-2 deficiency patients of Bulgarian descent. Sequencing analysis revealed the mutations p.Y188CfsX9 and p.G196S, and MLPA analysis showed a deletion of exon 1 in the SRD5A2 gene. The observed genetic substitutions were not detected in 76 additionally screened unrelated controls, but a heterozygous healthy carrier of the p.R171S mutation was found. This is the first study on the molecular basis of 5α-reductase-2 deficiency in Bulgaria. It suggests that the carrier frequency of mutations in the SRD5A2 gene might be noteworthy worldwide. There is no correlation between cultural aspects, location, and/or population size and the number of different mutations in SRD5A2 detected, and more efforts should be made to determine the prevalence of this condition in different geographic areas. Our study supports the importance of genetic testing in 46,XY DSD patients, especially in countries or regions where 5α-reductase-2 deficiency has not been reported so far.

Disorders in the initial steps of steroid hormone synthesis.

Steroidogenesis begins with cellular internalization of low-density lipoprotein particles and subsequent intracellular processing of cholesterol. Disorders in these steps include Adrenoleukodystrophy, Wolman Disease and its milder variant Cholesterol Ester Storage Disease, and Niemann-Pick Type C Disease, all of which may present with adrenal insufficiency. The means by which cholesterol is directed to steroidogenic mitochondria remains incompletely understood. Once cholesterol reaches the outer mitochondrial membrane, its delivery to the inner mitochondrial membrane is regulated by the steroidogenic acute regulatory protein (StAR). Severe StAR mutations cause classic congenital lipoid adrenal hyperplasia, characterized by lipid accumulation in the adrenal, adrenal insufficiency, and disordered sexual development in 46,XY individuals. The lipoid CAH phenotype, including spontaneous puberty in 46,XX females, is explained by a two-hit model. StAR mutations that retain partial function cause a milder, non-classic disease characterized by glucocorticoid deficiency, with lesser disorders of mineralocorticoid and sex steroid synthesis. Once inside the mitochondria, cholesterol is converted to pregnenolone by the cholesterol side-chain cleavage enzyme, P450scc, encoded by the CYP11A1 gene. Rare patients with mutations of P450scc are clinically and hormonally indistinguishable from those with lipoid CAH, and may also present as milder non-classic disease. Patients with P450scc defects do not have the massive adrenal hyperplasia that characterizes lipoid CAH, but adrenal imaging may occasionally fail to distinguish these, necessitating DNA sequencing.

Novel mutations of the SRD5A2 and AR genes in Thai patients with 46, XY disorders of sex development.

BACKGROUND: Abnormalities of dihydrotestosterone conversion [5α-reductase deficiency: online Mendelian inheritance in man (OMIM) 607306] or actions of androgens [partial androgen insensitivity syndrome (PAIS): OMIM 312300] during the 8th-12th weeks of gestation cause varying degrees of undervirilized external genitalia in 46, XY disorders of sex development (DSD) with increased testosterone production. The objective of the study was to determine clinical and genetic characteristics of Thai patients with 46, XY DSD. METHODS: A cross-sectional study was conducted in 46, XY DSD with increased testosterone production (n=43) evaluated by a human chorionic gonadotropin (hCG) stimulation test or clinical features consistent with 5α-reductase deficiency or PAIS. PCR sequencing of the entire coding regions of the SRD5A2 and AR genes was performed. Molecular modeling analysis of the androgen receptor-ligand-binding domain (AR-LBD) of a novel mutation was constructed. RESULTS: Mutations were found in seven patients (16.3%): five (11.6%) and two (4.7%) patients had mutations in SRD5A2 and AR, respectively. Two novel mutations, SRD5A2 c.383A>G (p.Y128C) and AR c.2176C>T (p.R726C), were identified. Dimensional structural analysis of the novel mutated AR (p.R726C) revealed that it affected the co-activator binding [binding function-3 (BF-3)], not the testosterone binding site. Short phallus length was associated with 5α-reductase deficiency. CONCLUSIONS: Around 16.3% of our patients with 46, XY DSD had 5α-reductase deficiency or PAIS. Two novel mutations of SRD5A2 and AR were identified. The novel mutated AR (p.R726C) might affect the co-activator binding (BF-3), not the testosterone binding site.

Human Sex Determination at the Edge of Ambiguity: INHERITED XY SEX REVERSAL DUE TO ENHANCED UBIQUITINATION AND PROTEASOMAL DEGRADATION OF A MASTER TRANSCRIPTION FACTOR.

A general problem is posed by analysis of transcriptional thresholds governing cell fate decisions in metazoan development. A model is provided by testis determination in therian mammals. Its key step, Sertoli cell differentiation in the embryonic gonadal ridge, is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in human SRY cause gonadal dysgenesis leading to XY female development (Swyer syndrome). Here, we have characterized an inherited mutation compatible with either male or female somatic phenotypes as observed in an XY father and XY daughter, respectively. The mutation (a crevice-forming substitution at a conserved back surface of the SRY high mobility group box) markedly destabilizes the domain but preserves specific DNA affinity and induced DNA bend angle. On transient transfection of diverse human and rodent cell lines, the variant SRY exhibited accelerated proteasomal degradation (relative to wild type) associated with increased ubiquitination; in vitro susceptibility to ubiquitin-independent ("default") cleavage by the 20S core proteasome was unchanged. The variant's gene regulatory activity (as assessed in a cellular model of the rat embryonic XY gonadal ridge) was reduced by 2-fold relative to wild-type SRY at similar levels of mRNA expression. Chemical proteasome inhibition restored native-like SRY expression and transcriptional activity in association with restored occupancy of a sex-specific enhancer element in principal downstream gene Sox9, demonstrating that the variant SRY exhibits essentially native activity on a per molecule basis. Our findings define a novel mechanism of impaired organogenesis, accelerated ubiquitin-directed proteasomal degradation of a master transcription factor leading to a developmental decision poised at the edge of ambiguity.

Correlation of androgen receptor and SRD5A2 gene mutations with pediatric hypospadias in 46, XY DSD children.

We performed an exploratory study by analyzing the correlation of 46, XY disorders of sex development (46, XY DSD) with androgen receptor (AR) and steroid 5α-reductase-2 (SRD5A2) gene mutations and a safety analysis of dihydrotestosterone (DHT) gel treatment for pediatric micropenis. We collected samples from 76 pediatric patients with 46, XY DSD and 50 healthy adult men with normal fertility as the control group. The pediatric patients were treated with DHT gel (0.1-0.3 mg/kg/day) for three to six months. The extended penis length, testicular volume, and multiple blood parameters were collected before treatment and one, three, and six months after treatment. Of the 76 cases with 46, XY DSD, 31.58% had hypospadias with micropenis and 6.58% had male pseudohermaphroditism. Through AR gene screening, it was found that 14 patients had AR point mutations and 22 patients had SRD5A2 mutations. After treatment with DHT, the penis length of the patients significantly improved after one, three, and six months of treatment, with longer treatment times resulting in greater improvement. Before treatment with DHT, the average serum DHT value of patients with 46, XY DSD was 24.29 pg/mL. After one, three, and six months of treatment, this value increased to 430.71, 328.9, and 323.6 pg/mL, respectively. We conclude that for pediatric patients who have male hermaphroditism or hypospadias with micropenis, AR and SRD5A2 gene mutation detection should be performed. Local application of DHT gel can promote penis growth effectively without systemic adverse reactions.

Mutational Profile of 10 Afflicted Egyptian Families with 17-ß-HSD-3 Deficiency.

This study aimed at the detection of HSD17B3 gene mutations in Egyptian patients with suspected diagnosis of 46,XY DSD due to 17-ß-HSD-3 deficiency and at evaluation of phenotype/genotype relationship of these mutations. The study was conducted on 11 patients of 10 families which were provisionally diagnosed to have 17-ß-HSD-3 enzyme deficiency. Karyotyping, hormonal evaluation of testosterone, x0394;4-androstenedione, and dihydrotestosterone, and sequencing analysis of the 11 exons of the HSD17B3 gene were done. Mutations in HSD17B3 were detected in exons 2, 7, 8, 10, and 11, and 6 novel mutations were determined in exons 1, 2, 7, and 8. Two patients showed compound heterozygous mutations, while 8 families had probands with homozygous mutations. The current study shows that 17-ß-HSD-3 deficiency is not an uncommon disorder among Egyptian DSD cases. It was evidenced that the mutational profile of the disease is rather heterogeneous, relatively different from those reported in other populations, and has a high degree of novel genetic defects.