A cluster of male pseudohermaphrodites with 5 alpha-reductase deficiency in Papua New Guinea

Dermatologic care of patients with differences of sex development

Background

Differences of sex development (DSD or disorders of sex development) are uncommon congenital conditions, characterized by atypical development of chromosomal, gonadal, or anatomic sex.

Objective

Dermatologic care is an important component of the multidisciplinary care needed for individuals with DSD. This article discusses the most common primary dermatologic manifestations of DSD in addition to the cutaneous manifestations of hormonal and surgical therapies in individuals with DSD.

Data sources

Published articles including case series and case reports on PubMed.

Study selections

Selection was conducted by examining existing literature with a team of multidisciplinary specialists.

Methods

Narrative review.

Limitations

This article was not conducted as a systematic review.

Results

In Klinefelter syndrome, refractory leg ulcers and incontinentia pigmenti have been described. Turner syndrome is associated with lymphatic malformations, halo nevi, dermatitis, and psoriasis. Virilization can be seen in some forms of congenital adrenal hyperplasia, where acne and hirsutism are common.

Conclusion

Dermatologists should consider teratogenic risk for treatments of skin conditions in DSD depending on pregnancy potential. Testosterone replacement, commonly used for Klinefelter syndrome, androgen insensitivity syndrome, 5-alpha reductase deficiency, gonadal dysgenesis, or ovotesticular DSD, may cause acne.

The Molecular Basis of 5α-Reductase Type 2 Deficiency

The 5α-reductase type 2 enzyme catalyzes the conversion of testosterone into dihydrotestosterone, playing a crucial role in male development. This enzyme is encoded by the SRD5A2 gene, which maps to chromosome 2 (2p23), consists of 5 exons and 4 introns, and encodes a 254 amino acid protein. Disruptions in this gene are the molecular etiology of a subgroup of differences of sex development (DSD) in 46,XY patients. Affected individuals present a large range of external genitalia undervirilization, ranging from almost typically female external genitalia to predominantly typically male external genitalia with minimal undervirilization, including isolated micropenis. This is an updated review of the implication of the SRD5A2 gene in 5α-reductase type 2 enzyme deficiency. For that, we identified 451 cases from 48 countries of this particular 46,XY DSD from the literature with reported variants in the SRD5A2 gene. Herein, we present the SRD5A2 mutational profile, the SRD5A2 polymorphisms, and the functional studies related to SRD5A2 variants to detail the molecular etiology of this condition.

Contribution of Clinical and Genetic Approaches for Diagnosing 209 Index Cases With 46,XY Differences of Sex Development

CONTEXT

Massively parallel sequencing (MPS) technologies have emerged as a first-tier approach for diagnosing several pediatric genetic syndromes. However, MPS has not been systematically integrated into the diagnostic workflow along with clinical/biochemical data for diagnosing 46,XY differences of sex development (DSD).

OBJECTIVE

To analyze the contribution of phenotypic classification either alone or in association with genetic evaluations, mainly MPS, for diagnosing a large cohort of 46,XY DSD patients.

DESIGN/PATIENTS

209 nonsyndromic 46,XY DSD index cases from a Brazilian DSD center were included. Patients were initially classified into 3 subgroups according to clinical and biochemical data: gonadal dysgenesis (GD), disorders of androgen secretion/action, and DSD of unknown etiology. Molecular genetic studies were performed by Sanger sequencing and/or MPS.

RESULTS

Clinical/biochemical classification into either GD or disorders of hormone secretion/action was obtained in 68.4% of the index cases. Among these, a molecular diagnosis was obtained in 36% and 96.5%, respectively. For the remainder 31.6% classified as DSD of clinically unknown etiology, a molecular diagnosis was achieved in 31.8%. Overall, the molecular diagnosis was achieved in 59.3% of the cohort. The combination of clinical/biochemical and molecular approaches diagnosed 78.9% of the patients. Clinical/biochemical classification matched with the genetic diagnosis in all except 1 case. DHX37 and NR5A1 variants were the most frequent genetic causes among patients with GD and DSD of clinical unknown etiology, respectively.

CONCLUSIONS

The combination of clinical/biochemical with genetic approaches significantly improved the diagnosis of 46,XY DSD. MPS potentially decreases the complexity of the diagnostic workup as a first-line approach for diagnosing 46,XY DSD.

Advances in Knowledge of Androgens: How Intentional and Accidental Neurosteroid Changes Inform Us of Their Action and Role

Purpose of Review

Here, we summarize current knowledge of androgens’ action gained over the recent years.

Recent Findings

Neurosteroids are produced in the brain and peripheral nerves, independent of endocrine glands have been investigated for how they are regulated, and have actions via non-steroid receptor targets to mediate social, affective, and cognitive behavior and to protect the brain. Androgens’ organizing actions in the peri-natal period have effects throughout the lifetime that may be recapitulated later in life during critical periods and at times of challenge. Developmental changes in androgens occur during mid-childhood, adrenarche, puberty, adolescence, young adulthood, middle age, and andropause. Changes in androgens with a 5α-reductase inhibitor, such as finasteride, result in disruptions in organizational and activational functions of androgens that can be unremitting.

Summary

Normal developmental or perturbation in androgens through other means can cause changes in androgen-sensitive phenotypes throughout the lifespan, in part through actions of neurosteroids.

New insights into 5α-reductase type 2 deficiency based on a multi-centre study: regional distribution and genotype-phenotype profiling of SRD5A2 in 190 Chinese patients

BACKGROUND

The 5α-reductase type 2 (5α-RD2) deficiency caused by mutations in the steroid 5α-reductase 2 (SRD5A2) gene results in variable degrees of undervirilisation in patients with 46,XY disorders of sex development. This study aims to profile the regional distribution and phenotype-genotype characteristics of SRD5A2 in a large Chinese 5α-RD2 deficiency cohort through multi-centre analysis.

METHODS

190 subjects diagnosed with 5α-RD2 deficiency were consecutively enrolled from eight medical centres in China. Their clinical manifestations and genetic variants were analysed.

RESULTS

Hypospadias (isolated or combined with microphallus and/or cryptorchidism) was fairly common in the enrolled subjects (66.32%). 42 variants, including 13 novel variants, were identified in SRD5A2. Homozygous and compound heterozygous mutations presented in 38.42% and 61.58% of subjects, respectively, and predominated in exons 1, 4 and 5. The most prevalent variant was c.680G > A (52.37%), followed by c.16C > T, (10.79%), c.607G > A, (9.21%) and c.737G > A, (8.95%). However, their distributions were different: c.680G > A was more common in South China than in North China (62.62% vs 39.16%, p < 0.001), whereas the regional prevalence of c.16C > T was reversed (6.07% vs 16.87%, p = 0.001). Furthermore, c.680G > A prevailed in cases with normal meatus (68.75%) or distal hypospadias (66.28%), compared with those with proximal hypospadias (35.54%, p < 0.001). However, cases with proximal hypospadias showed a higher frequency of c.16C > T (20.48%) than those with normal meatus (3.13%) or distal hypospadias (3.49%, p < 0.001).

CONCLUSIONS

This study profiled variable phenotypic presentation and wide mutational spectrum of SRD5A2, revealing its distinctive regional distribution in Chinese patients and further shaping the founder effect and genotype-phenotype correlation of SRD5A2.

Genotype-phenotype correlation, gonadal malignancy risk, gender preference, and testosterone/dihydrotestosterone ratio in steroid 5-alpha-reductase type 2 deficiency: a multicenter study from Turkey

BACKGROUND

Studies regarding genetic and clinical characteristics, gender preference, and gonadal malignancy rates for steroid 5-alpha-reductase type 2 deficiency (5α-RD2) are limited and they were conducted on small number of patients.

OBJECTIVE

To present genotype-phenotype correlation, gonadal malignancy risk, gender preference, and diagnostic sensitivity of serum testosterone/dihydrotestosterone (T/DHT) ratio in patients with 5α-RD2.

MATERIALS AND METHODS

Patients with variations in the SRD5A2 gene were included in the study. Demographic characteristics, phenotype, gender assignment, hormonal tests, molecular genetic data, and presence of gonadal malignancy were evaluated.

RESULTS

A total of 85 patients were included in the study. Abnormality of the external genitalia was the most dominant phenotype (92.9%). Gender assignment was male in 58.8% and female in 29.4% of the patients, while it was uncertain for 11.8%. Fourteen patients underwent bilateral gonadectomy, and no gonadal malignancy was detected. The most frequent pathogenic variants were p.Ala65Pro (30.6%), p.Leu55Gln (16.5%), and p.Gly196Ser (15.3%). The p.Ala65Pro and p.Leu55Gln showed more undervirilization than the p.Gly196Ser. The diagnostic sensitivity of stimulated T/DHT ratio was higher than baseline serum T/DHT ratio, even in pubertal patients. The cut-off values yielding the best sensitivity for stimulated T/DHT ratio were ≥ 8.5 for minipuberty, ≥ 10 for prepuberty, and ≥ 17 for puberty.

CONCLUSION

There is no significant genotype-phenotype correlation in 5α-RD2. Gonadal malignancy risk seems to be low. If genetic analysis is not available at the time of diagnosis, stimulated T/DHT ratio can be useful, especially if different cut-off values are utilized in accordance with the pubertal status.

Using Human Genetics to Drive Drug Discovery: A Perspective

The probability of success of developing medicines to treat human disease can be improved by leveraging human genetics. Different types of genetic data and techniques, including genome-wide association, whole-exome sequencing, and whole-genome sequencing, can be used to gain insight into human disease. Layering different types of genetic evidence from Mendelian disease, coding variants, and common variation can bolster support for a genetic target. Human knockouts offer the potential to perform reverse genetic screens in humans to identify physiologically relevant targets. Other components of a good genetic target include protective loss-of-function mutations, some degree of known biology, tractability, and a clean on-target safety profile. In addition to using human genetics to inspire new drug programs, phenome-wide association studies can be used to identify alternative indications or repurposing opportunities. This information can be combined into a 5-step approach for selecting a genetic target for validation, which is presented in detail in this review. Finally, current challenges in leveraging human genetics are highlighted, including the difficulties translating certain types of genetic data, relatively small number of bona fide disease-associated coding rare variants, and current sample sizes of large well-curated biobanks linked to comprehensive genetic information.

Characterising SRD5A2 Gene Variants in 37 Indonesian Patients with 5-Alpha-Reductase Type 2 Deficiency

The 5-alpha-reductase type 2 deficiency (5ARD2) is an autosomal recessive condition associated with impairment in the conversion of testosterone to dihydrotestosterone. This condition leads to undervirilisation in 46,XY individuals. To date, there have been more than 100 variations identified in the gene responsible for 5ARD2 development (steroid 5-alpha-reductase 2, SRD5A2). However, few studies have examined the molecular characterisation of Indonesian 5ARD2 cases. In the current study, we analysed 37 subjects diagnosed with 46,XY DSD (disorders of sex development) with confirmed variations in the SRD5A2 gene. We examined results from testosterone/dihydrotestosterone (T/DHT) and urinary etiocholanolone/androsterone (Et/An) ratios, as well as from molecular and clinical analyses. Twelve variants in the SRD5A2 gene were identified, and 6 of which were novel, namely, c.34-38delGinsCCAGC, p.Arg50His, p.Tyr136 ^∗ , p.Gly191Arg, p.Phe194Ile, and p.Ile253Val variants. Moreover, we determined that 20 individuals contained harmful mutations, while the remaining 17 variants were benign. Those containing harmful mutations exhibited more severe phenotypes with median external genitalia masculinisation scores (EMS) of 3 (1.5-9) and were more likely to be diagnosed at a later age, reared as female, and virilised at pubertal age. In addition, the respective sensitivities for detecting severe 5ARD2 cases using T/DHT (cutoff: 10) and urinary Et/An ratios (cutoff: 0.95) were 85% and 90%, whereas mild cases were only identified with 64.7% and 47.1% sensitivity, respectively. Although we were unable to identify clear correlations between genotypic and phenotypic characteristics in this study, we clearly showed that individuals who were homozygous or compound heterozygous for any of the harmful mutations were more likely to exhibit classic 5ARD2 phenotypes, lower EMS, female assignment at birth, and virilisation during puberty. These results serve to inform the development of improved clinical and molecular 5ARD2 diagnostic approaches, specifically in Indonesian patients.

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.

Mental Health and Disorders of Sex Development/Intersex Conditions in Iranian Culture: Congenital Adrenal Hyperplasia, 5-α Reductase Deficiency-Type 2, and Complete Androgen Insensitivity Syndrome

Sixty-one patients (22 patients with congenital adrenal hyperplasia [CAH] with a mean age of 14.86 years [range, 5-23], 20 patients with 5-α reductase deficiency type 2 [5α-RD-2] with a mean age of 19.5 years [range, 5-29], and 19 patients with complete androgen insensitivity syndrome [CAIS] with a mean age of 18.26 years [range, 5-28]) were evaluated using the Kiddie Schedule for Affective Disorders and Schizophrenia, the Structured Clinical Interview for DSM-IV Axis I, Axis II, and the Global Assessment Functioning Scale. All participants were female-assigned at birth. Ten patients (16.4%) transitioned to the male gender. Overall, 68% of patients had one or more lifetime Axis I disorders, including 63.6% of the CAH participants, 90% of 5α-RD-2 participants, and 52.6% of the CAIS participants. The most commonly observed were affective disorders (27.9%), gender identity disorder (27.9%), and anxiety (16.4%). Our study demonstrates that mental health of Iranian patients with DSD is at risk. This might be due to the fact that patients with DSD conditions are mostly treated medically and their mental health is often superficially addressed in developing countries such as Iran, at least in the past. We argue that it is important to pay attention to the mental health issues of patients with DSD and focus on specific issues, which may vary cross-culturally.

Effects of chromosomal sex and hormonal influences on shaping sex differences in brain and behavior: Lessons from cases of disorders of sex development

Sex differences in brain development and postnatal behavior are determined largely by genetic sex and in utero gonadal hormone secretions. In humans however, determining the weight that each of these factors contributes remains a challenge because social influences should also be considered. Cases of disorders of sex development (DSD) provide unique insight into how mutations in genes responsible for gonadal formation can perturb the subsequent developmental hormonal milieu and elicit changes in normal human brain maturation. Specific forms of DSDs such as complete androgen insensitivity syndrome (CAIS), congenital adrenal hyperplasia (CAH), and 5α-reductase deficiency syndrome have variable effects between males and females, and the developmental outcomes of such conditions are largely dependent on sex chromosome composition. Medical and psychological works focused on CAH, CAIS, and 5α-reductase deficiency have helped form the foundation for understanding the roles of genetic and hormonal factors necessary for guiding human brain development. Here we highlight how the three aforementioned DSDs contribute to brain and behavioral phenotypes that can uniquely affect 46,XY and 46,XX individuals in dramatically different fashions. © 2016 Wiley Periodicals, Inc.

Emerging issues in disorders/differences of sex development (DSD)

Disorders/Differences of Sex Development (DSD), as defined by the 2006 Consensus Statement, are "congenital conditions in which development of chromosomal, gonadal, or anatomic sex is atypical." They represent a spectrum of chronic medical conditions collectively affecting about 1% of the population and are associated with increased risk of infertility, cancer, and psychosocial distress. Clinical management in DSD is subject to multiple controversies about gender assignment, the timing and appropriateness of genital surgery and the approach to disclosure. There is dissent within and between stakeholders (healthcare providers, advocacy groups, families) regarding what constitutes optimal care. This special issue investigates the progress made as well as the uncertainties remaining a decade after the consensus statement and the gaps to be filled by future research and improved clinical practice. It discusses the increasing intricacy of genetic variant interpretation in the era of next-generation sequencing and the associated complexity of phenotypic variability. The issue tackles ethical dilemmas and the complicated decision-making process of assignment of sex of rearing at birth in cases of 5-alpha reductase type 2 deficiency, surveys delivery of clinical services in the United States, discusses challenges of interdisciplinary care and of educating patients and parents about DSD,and reviews the factors predisposing to gonadal tumor and their consequences on clinical management.

Reprint of "Steroid 5α-reductase 2 deficiency"

Dihydrotestosterone is a potent androgen metabolite formed from testosterone by action of 5α-reductase isoenzymes. Mutations in the type 2 isoenzyme cause a disorder of 46,XY sex development, termed 5α-reductase type 2 deficiency and that was described forty years ago. Many mutations in the encoding gene have been reported in different ethnic groups. In affected 46,XY individuals, female external genitalia are common, but Mullerian ducts regress, and the internal urogenital tract is male. Most affected males are raised as females, but virilization occurs at puberty, and male social sex develops thereafter with high frequency. Fertility can be achieved in some affected males with assisted reproduction techniques, and adults with male social sex report a more satisfactory sex life and quality of life as compared to affected individuals with female social sex.

Steroid 5α-reductase 2 deficiency

Dihydrotestosterone is a potent androgen metabolite formed from testosterone by action of 5α-reductase isoenzymes. Mutations in the type 2 isoenzyme cause a disorder of 46,XY sex development, termed 5α-reductase type 2 deficiency and that was described forty years ago. Many mutations in the encoding gene have been reported in different ethnic groups. In affected 46,XY individuals, female external genitalia are common, but Mullerian ducts regress, and the internal urogenital tract is male. Most affected males are raised as females, but virilization occurs at puberty, and male social sex develops thereafter with high frequency. Fertility can be achieved in some affected males with assisted reproduction techniques, and adults with male social sex report a more satisfactory sex life and quality of life as compared to affected individuals with female social sex.

Differential expression of 5-alpha reductase isozymes in the prostate and its clinical implications

The development of human benign or malignant prostatic diseases is closely associated with androgens, primarily testosterone (T) and dihydrotestosterone (DHT). T is converted to DHT by 5-alpha reductase (5-AR) isozymes. Differential expression of 5-AR isozymes is observed in both human benign and malignant prostatic tissues. 5-AR inhibitors (5-ARI) are commonly used for the treatment of benign prostatic hyperplasia (BPH) and were once promoted as chemopreventive agents for prostate cancer (PCa). This review discusses the role of the differential expression of 5-AR in the normal development of the human prostate and in the pathogenesis and progression of BPH and PCa.

The effect of 5α-reductase-2 deficiency on human fertility

A most interesting and intriguing male disorder of sexual differentiation is due to 5α-reductase-2 isoenzyme deficiency. These male infants are born with ambiguous external genitalia due to a deficiency in their ability to catalyze the conversion of T to dihydrotestosterone. Dihydrotestosterone is a potent androgen responsible for differentiation of the urogenital sinus and genital tubercle into the external genitalia, urethra, and prostate. Affected males are born with a clitoral-like phallus, bifid scrotum, hypospadias, blind shallow vaginal pouch from incomplete closure of the urogenital sinus, and a rudimentary prostate. At puberty, the surge in mainly T production prompts virilization, causing most boys to choose gender reassignment to male. Fertility is a challenge for affected men for several reasons. Uncorrected cryptorchidism is associated with low sperm production, and there is evidence of defective transformation of spermatogonia into spermatocytes. The underdeveloped prostate and consequent low semen volumes affect sperm transport. In addition, semen may not liquefy due to a lack of prostate-specific antigen. In the present review, we discuss the 5α-reductase-2 deficiency syndrome and its impact on human fertility.

Clinical biochemistry of dihydrotestosterone

Dihydrotestosterone (DHT) is the most potent natural androgen in humans. There has been an increasing interest in this androgen and its role in the development of primary and secondary sexual characteristics as well as its potential roles in diseases ranging from prostate and breast cancer to Alzheimer's disease. Despite the range of pathologies shown to involve DHT there is little evidence for measurement of serum DHT in the management of these diseases. In this review we describe the physiology of DHT production and action, summarize current concepts in the role of DHT in the pathogenesis of various disorders of sexual development, compare current methods for the measurement of DHT and conclude on the clinical utility of DHT measurement. The clinical indications for the measurement of DHT in serum are: investigation of 5α reductase deficiency in infants with ambiguous genitalia and palpable gonads; men with delayed puberty and/or undescended testes; and to confirm the presence of active testicular tissue. Investigation is aided by the use of human chorionic gonadotrophin stimulation. Due to paucity of published data on this procedure, it is important to follow guidelines prescribed by the laboratory performing the analysis to ensure accurate interpretation.

The critical role of androgens in prostate development

Androgens are involved in every aspect of prostate development, growth, and function from early in male embryogenesis to prostatic hyperplasia in aging men and dogs. Likewise, androgen deprivation at any phase of life causes a decrease in prostate cell number and DNA content. The process by which the circulating androgen testosterone is converted to dihydrotestosterone in the tissue and dihydrotestosterone in turn gains access to the nucleus where it regulates gene expression, largely via interaction with a receptor protein, is understood, but the downstream control mechanisms by which hormonal signals are translated into differentiation, growth, and function are being unraveled.

Why boys will be boys: two pathways of fetal testicular androgen biosynthesis are needed for male sexual differentiation

Human sexual determination is initiated by a cascade of genes that lead to the development of the fetal gonad. Whereas development of the female external genitalia does not require fetal ovarian hormones, male genital development requires the action of testicular testosterone and its more potent derivative dihydrotestosterone (DHT). The "classic" biosynthetic pathway from cholesterol to testosterone in the testis and the subsequent conversion of testosterone to DHT in genital skin is well established. Recently, an alternative pathway leading to DHT has been described in marsupials, but its potential importance to human development is unclear. AKR1C2 is an enzyme that participates in the alternative but not the classic pathway. Using a candidate gene approach, we identified AKR1C2 mutations with sex-limited recessive inheritance in four 46,XY individuals with disordered sexual development (DSD). Analysis of the inheritance of microsatellite markers excluded other candidate loci. Affected individuals had moderate to severe undervirilization at birth; when recreated by site-directed mutagenesis and expressed in bacteria, the mutant AKR1C2 had diminished but not absent catalytic activities. The 46,XY DSD individuals also carry a mutation causing aberrant splicing in AKR1C4, which encodes an enzyme with similar activity. This suggests a mode of inheritance where the severity of the developmental defect depends on the number of mutations in the two genes. An unrelated 46,XY DSD patient carried AKR1C2 mutations on both alleles, confirming the essential role of AKR1C2 and corroborating the hypothesis that both the classic and alternative pathways of testicular androgen biosynthesis are needed for normal human male sexual differentiation.

Minireview: Hormones and human sexual orientation

Many people believe that sexual orientation (homosexuality vs. heterosexuality) is determined by education and social constraints. There are, however, a large number of studies indicating that prenatal factors have an important influence on this critical feature of human sexuality. Sexual orientation is a sexually differentiated trait (over 90% of men are attracted to women and vice versa). In animals and men, many sexually differentiated characteristics are organized during early life by sex steroids, and one can wonder whether the same mechanism also affects human sexual orientation. Two types of evidence support this notion. First, multiple sexually differentiated behavioral, physiological, or even morphological traits are significantly different in homosexual and heterosexual populations. Because some of these traits are known to be organized by prenatal steroids, including testosterone, these differences suggest that homosexual subjects were, on average, exposed to atypical endocrine conditions during development. Second, clinical conditions associated with significant endocrine changes during embryonic life often result in an increased incidence of homosexuality. It seems therefore that the prenatal endocrine environment has a significant influence on human sexual orientation but a large fraction of the variance in this behavioral characteristic remains unexplained to date. Genetic differences affecting behavior either in a direct manner or by changing embryonic hormone secretion or action may also be involved. How these biological prenatal factors interact with postnatal social factors to determine life-long sexual orientation remains to be determined.

46,XY DSD due to impaired androgen production

Disorders of androgen production can occur in all steps of testosterone biosynthesis and secretion carried out by the foetal Leydig cells as well as in the conversion of testosterone into dihydrotestosterone (DHT). The differentiation of Leydig cells from mesenchymal cells is the first walk for testosterone production. In 46,XY disorders of sex development (DSDs) due to Leydig cell hypoplasia, there is a failure in intrauterine and postnatal virilisation due to the paucity of interstitial Leydig cells to secrete testosterone. Enzymatic defects which impair the normal synthesis of testosterone from cholesterol and the conversion of testosterone to its active metabolite DHT are other causes of DSD due to impaired androgen production. Mutations in the genes that codify the enzymes acting in the steps from cholesterol to DHT have been identified in affected patients. Patients with 46,XY DSD secondary to defects in androgen production show a variable phenotype, strongly depending of the specific mutated gene. Often, these conditions are detected at birth due to the ambiguity of external genitalia but, in several patients, the extremely undervirilised genitalia postpone the diagnosis until late childhood or even adulthood. These patients should receive long-term care provided by multidisciplinary teams with experience in this clinical management.

Detection of the G34R mutation in the 5 alpha reductase 2 gene by allele specific PCR and its linkage to the 89L allele among Egyptian cases

The 5 alpha-reductase type 2 deficiency is an autosomal recessive disorder of sexual development among 46,XY individuals. In Egypt, there is a prevalence of a G34R disease underlying mutation. This study aimed to devise a rapid diagnostic method based on allele specific PCR (AS-PCR) and a linked polymorphism (V89L). The results showed that one set of primers was capable to differentiate between normal, heterozygous, and affected individuals efficiently. All 34R mutation carrying sequences had 100% linkage to the 89L allele, contrasting normal ones with low 89L frequencies. This linkage infers a founder effect among Egyptians having G34R mutation.

Gender identity of children and young adults with 5alpha-reductase deficiency

Male pseudohermaphroditism (46,XY DSD) due to 5alpha-reductase deficiency has been recognized for the last few decades. There is scant literature on this entity in India. We compiled data on five patients with this disorder. Four of our five patients were reared as females. Our assessment of these children reveals that they had male gender identity from childhood. Three of the four reared as females chose to change gender role at adolescence, while the fourth is still prepubertal. We conclude that all these patients had male gender identity from early childhood. The parents took note of this only after the appearance of male secondary sexual characteristics at puberty, thereby giving an impression of change in gender identity and gender role.

Bone mineral density in the complete androgen insensitivity and 5alpha-reductase-2 deficiency syndromes

CONTEXT

Subjects with complete androgen insensitivity (CAI) and 5alpha-reductase-2 deficiency (5alphaRD-2) are natural human models to study the direct effect of androgens on bone mineral density (BMD).

OBJECTIVE

The objective of this study was to test the hypothesis that androgens have a direct effect on BMD in men.

DESIGN

This was a prospective, observational study (1989-1999) using dual energy x-ray absorptiometry.

SETTING

The study was set in an outpatient specialty referral center.

PATIENTS OR OTHER PARTICIPANTS

All known subjects with these conditions (12 CAI and 16 5alphaRD-2) from diverse sociodemographic backgrounds were recruited for the study.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE

Mean Z score and weight-matched Z score at lumbar spine and femoral neck for CAI and 5alphaRD-2 subjects were determined.

RESULTS

Twelve CAI subjects had mean Z score at L2-L4 of -2.84 (+/-0.97, P < 0.001) and a mean weight-matched Z score of -2.52 (+/-0.94, P < 0.001). The mean Z score at the femoral neck was -1.33 (+/-0.91, P < 0.001) and the mean weight-matched Z score was -1.10 (+/-0.82, P = 0.001). Sixteen 5alphaRD-2 subjects had a mean Z score at L2-L4 of -0.84 (+/-1.29, P = 0.02) and a mean weight-matched Z score for 15 of 16 patients of -0.44 (+/-1.08, P = 0.14). The mean Z score at the femoral neck was 0.14 (+/-1.02, P = 0.58) and the mean weight-matched Z score for 15 of 16 patients was 0.49 (+/-0.94, P = 0.06). Therefore, in CAI subjects, BMD was significantly decreased in the spine and hip. 5alphaRD-2 subjects had normal BMD values.

CONCLUSIONS

1) Androgens are of direct importance in the development and/or maintenance of BMD; and 2) testosterone and/or low levels of dihydrotestosterone appear to be sufficient for BMD development and/or maintenance.

Potential determinant factors of sexual identity in ambiguous genitalia

This is a review of literature scanning the potential factors which may affect Sexual Identity (S.I.) and Gender Identity (G.I.) in patients with ambiguous genitalia. Definitions of these concepts are outlined. Genetic, gonadal, hormonal, social and cultural pressures are reviewed as well as lessons to learn from clinical experiences and outcomes. Current criteriae used to assign gender in a child with ambiguous genitalia are discussed including medical and surgical criteriae as well as cultural disruptors. At the dawn of the third millennium, it is remarkable how little we know about the establishment of our individual and social identities.

Gender change in 46,XY persons with 5alpha-reductase-2 deficiency and 17beta-hydroxysteroid dehydrogenase-3 deficiency

Individuals with 5alpha-reductase-2 deficiency (5alpha-RD-2) and 17beta-hydroxysteroid dehydrogenase-3 deficiency (17beta-HSD-3) are often raised as girls. Over the past number of years, this policy has been challenged because many individuals with these conditions develop a male gender identity and make a gender role change after puberty. The findings also raised doubts regarding the hypothesis that children are psychosexually neutral at birth and emphasized the potential role of prenatal brain exposure to androgens in gender development. If prenatal exposure to androgens is a major contributor to gender identity development, one would expect that all, or nearly all, affected individuals, even when raised as girls, would develop a male gender identity and make a gender role switch later in life. However, an estimation of the prevalence of gender role changes, based on the current literature, shows that gender role changes occur frequently, but not invariably. Gender role changes were reported in 56-63% of cases with 5alpha-RD-2 and 39-64% of cases with 17beta-HSD-3 who were raised as girls. The changes were usually made in adolescence and early adulthood. In these two syndromes, the degree of external genital masculinization at birth does not seem to be related to gender role changes in a systematic way.

Isoenzyme type 1 of 5alpha-reductase is abundantly transcribed in normal human genital skin fibroblasts and may play an important role in masculinization of 5alpha-reductase type 2 deficient males

OBJECTIVE

5alpha-reductase enzymes reduce testosterone (T) to the most potent androgen dihydrotestosterone (DHT). Two isoenzymes are known to day. While the type 2-enzyme (5RII) is predominantly expressed in male genital tissues and mutations are known to cause a severe virilization disorder in genetic males, the role of the type 1-enzyme (5RI) in normal male androgen physiology is unclear. We investigated whether 5RI is transcribed in normal male genital skin fibroblasts (GSFs) and if the transcription is regulated by age or by androgens themselves.

METHODS

GSF from 14 normally virilized males of different ages, ranging from 8 months to 72 years, obtained at circumcision were cultured. Total RNA was isolated after incubation for 48 h with 100 nM T or without androgens. Each sample was amplified in triplicate by real-time PCR with porphobilinogen desaminase as a housekeeping gene used for semiquantification. Selected cultures were analyzed after incubation with 10 and 100 nM T and 1 and 100 nM DHT for 24, 48 and 120 h.

RESULTS

5RI was transcribed in all investigated samples with a 4.5-fold variability in the mRNA concentration of different individuals. However, neither age-related regulation nor significant influence of T or DHT on the transcription rate was discovered.

CONCLUSION

Since 5RI is abundantly transcribed in GSFs, we hypothesize that this isoenzyme may play important roles in the androgen physiology of normally virilized males and may contribute to masculinization in 5RII-deficient males at the time of puberty.

Choice of gender in 5alpha-reductase deficiency: a moving target

Steroid 5alpha-reductase deficiency is a rare, male-limited autosomal recessive disorder caused by mutation in the SRD5A2 gene resulting in a deficiency of dihydrotestosterone (DHT) during fetal development. Here we report an affected 46,XY adolescent who was born with incompletely virilized genitalia and was raised in the female gender. At 12 years of age, the patient requested feminizing genital surgery. Surgery was withheld and psychiatric counseling was instituted. At 14 years of age, the patient's gender identity and role appeared to be in transition from a female to an increasingly male gender. This case demonstrates that in patients with disorders such as 5alpha-reductase deficiency, in which significant prenatal androgen exposures are combined with postnatal virilization, adult gender identity and gender role may be a dynamic process that is not complete until well after adolescence.

Lower genital tract disease in children and adolescents--a review

Conditions affecting the lower genital tract of female children and adolescents are often significantly different than those seen in the adult. The purpose of this review is to provide an overview of vulvar, vaginal, and cervical conditions that may be encountered only rarely by the more generalized practitioner.

Gender identity in XY intersexuality

The following syndromes of XY intersexuality are reviewed: 5alpha-reductase-2 deficiency, 17beta-hydroxysteroid dehydrogenase-3 deficiency, and complete and partial androgen insensitivity with attention focused on issues of gender identity. Each syndrome, with its unique presentation, provides an opportunity to explore the relative effects of nature (androgens) versus nurture (sex of rearing) in gender identity development. The phenomenon of gender role reversal in these conditions is described and theories on the determinants of gender identity formation are proposed. Issues of importance to psychiatrists in treating patients who have these conditions also are discussed.

A late sex reassignment in 5-alpha reductase deficiency: case report

The syndrome of male pseudohermaphroditism, caused by a deficiency of the enzyme 5-alpha reductase, results in a selective decrease in dihyrotestosterone. Culture is an important part of the context in which decisions are made on sex assignment of patients with abnormalities of the external genitalia. In Turkey, patients with ambiguious genitalia are diagnosed very late and corrective surgery is usually performed during or after puberty. Here we present a case with 5-alpha reductase deficiency who was diagnosed at puberty and followed-up for 10 years.

Molecular epidemiology of hypospadias: Review of genetic and environmental risk factors

Hypospadias is one of the most common congenital anomalies in the United States, occurring in approximately 1 in 125 live male births. It is characterized by altered development of the urethra, foreskin, and ventral surface of the penis. In this review, the embryology, epidemiology, risk factors, genetic predisposition, and likely candidate genes for hypospadias are described. Recent reports have identified increases in the birth prevalence of mild and severe forms of hypospadias in the United States from the 1960s to the present. Studies in consanguineous families and small case series have identified allelic variants in genes controlling androgen action and metabolism that cause hypospadias, but the relevance of these findings to the general population is unknown. Concern has also focused on whether exposure to endocrine disrupting chemicals (EDC) with antiandrogenic activity is the cause of this increase. Hypospadias is believed to have a multifactorial etiology in which allelic variants in genes controlling androgen action and metabolism predispose individuals to develop this condition. When genetic susceptibility is combined with exposure to antiandrogenic agents, a threshold is surpassed, resulting in the manifestation of this birth defect. A clear role for exposure to antiandrogenic environmental chemicals has yet to be established in the etiology of hypospadias, although results from laboratory animal models indicate that a number of environmental chemicals could be implicated. Molecular epidemiology studies that simultaneously examine the roles of allelic variants in genes controlling androgen action and metabolism, and environmental exposures are needed to elucidate the risk factors for these anomalies and the causes of the increased rate of hypospadias.

Surgical management of ambiguous genitalia

The surgical management of children born with ambiguous genitalia has always been difficult, subject to evolving attitudes and techniques, and at times controversial. Standard protocols have stressed the need for early diagnosis, gender assignment, and appropriate surgery in infancy.(1) In recent years some authors, backed by patient support groups, have claimed that such surgery is damaging or mutilating and, as it is essentially cosmetic, should not be performed until the fully informed consent of the patient could be obtained-that is, when the child becomes "Gillick competent".(2-)(4) There are, however, so many specific issues related to the different diagnostic groups that such a policy would seem to be too prescriptive.

Sexual differentiation of the human hypothalamus

Functional sex differences in reproduction, gender and sexual orientation and in the incidence of neurological and psychiatric diseases are presumed to be based on structural and functional differences in the hypothalamus and other limbic structures. Factors influencing gender, i.e., the feeling to be male or female, are prenatal hormones and compounds that change the levels of these hormones, such as anticonvulsants, while the influence of postnatal social factors is controversial. Genetic factors and prenatal hormone levels are factors in the determination of sexual orientation, i.e. heterosexuality, bisexuality or homosexuality. There is no convincing evidence for postnatal social factors involved in the determination of sexual orientation. The period of overt sexual differentiation of the human hypothalamus occurs between approximately four years of age and adulthood, thus much later than is generally presumed, although the late sexual differentiation may of course be based upon processes that have already been programmed in mid-pregnancy or during the neonatal period. The recently reported differences in a number of structures in the human hypothalamus and adjacent structures depend strongly on age. Replication of these data is certainly necessary. Since the size of brain structures may be influenced by premortem factors (e.g. agonal state) and postmortem factors (e.g. fixation time), one should not only perform volume measurements, but also estimate a parameter that is not dependent on such factors as, i.e., total cell number of the brain structure in question. In addition, functional differences that depend on the levels of circulating hormones in adulthood have been observed in several hypothalamic and other brain structures. The mechanisms causing sexual differentiation of hypothalamic nuclei, the pre- and postnatal factors influencing this process, and the exact functional consequences of the morphological and functional hypothalamic differences await further elucidation.

Molecular analysis of 5alpha-reductase type 2 gene in eight unrelated egyptian children with suspected 5alpha-reductase deficiency: prevalence of the G34R mutation

OBJECTIVE

Analysis of the 5alpha-reductase type 2 (SRD5A2) gene in Egyptian patients with suspected 5alpha-reductase (5alphaR) deficiency.

PATIENTS AND METHODS

Eight unrelated patients, originating from different geographical areas of Egypt, were referred to the Department of Pediatrics. Six prepubertal and two postpubertal patients presented with ambiguous genitalia. Four were being reared as females while the others were being reared as males. Six patients were products of consanguineous marriages. All patients had 46,XY karyotype. Basal and post-human chorionic gonadotrophin (hCG) stimulation plasma levels of testosterone and dihydrotestosterone were determined. Sequencing of five exons of the SRD5A2 gene was carried out.

RESULTS

All patients had normal male testosterone levels, both basal and post-hCG stimulation. The T/DHT ratio was available for six patients and showed values that ranged from normal to high. Three different homozygous mutations were identified. One patient carried a Y235F substitution and two had a N160D substitution. Interestingly, all five of the other patients had the G34R mutation. The parents were heterozygous for the mutations, although the mother of one patient was homozygous for the G34R mutation.

CONCLUSION

Among eight unrelated Egyptian children with 5alpha-reductase deficiency, the G34R mutation was identified in five patients. The high consanguinity rate in Egypt suggests a common ancestor with a founder gene effect in cases of G34R mutation.

Sex differences in the hypothalamus in the different stages of human life

Quite a number of structural and functional sex differences have been reported in the human hypothalamus and adjacent structures that may be related to not only reproduction, sexual orientation and gender identity, but also to the often pronounced sex differences in prevalence of psychiatric and neurological diseases. One of the recent focuses of interest in this respect is the possible beneficial effect of sex hormones on cognition in Alzheimer patients. The immunocytochemical localization of estrogen receptors (ER) alpha, beta and androgen receptors has shown that there are indeed numerous targets for sex hormones in the adult human brain. Observations in the infundibular nucleus have, however, indicated that in this brain area the hyperactivity resulting from a lack of estrogens in the menopause seems to protect females against Alzheimer changes, in contrast to males. It is thus quite possible that estrogen replacement therapy may, in these brain areas, lead to inhibition of neuronal metabolism and thus to the same proportion of Alzheimer changes as are observed in men. Knowledge about the functional sex differences in the brain and the effect of sex hormones on neuronal metabolism may thus provide clues not only for the possible beneficial effects of these hormones (e.g., on cognition or hypertension), but also on possible central side effects of estrogen replacement therapy.

Androgens and male physiology the syndrome of 5alpha-reductase-2 deficiency

Dihydrotestosterone (DHT), a potent androgen, is converted from testosterone by 5alpha-reductase isozymes. There are two 5alpha-reductase isozymes, type 1 and type 2 in humans and animals. These two isozymes have differential biochemical and molecular features. Mutations in type 2 isozyme cause male pseudohermaphroditism, and many mutations have been reported from various ethnic groups. The affected 46XY individuals have high normal to elevated plasma testosterone levels with decreased DHT levels and elevated testosterone/DHT ratios. They have ambiguous external genitalia at birth so that they are believed to be girls and are often raised as such. However, Wolffian differentiation occurs normally and they have epididymides, vas deferens and seminal vesicles. Virilization occurs at puberty frequently with a gender role change. The prostate in adulthood is small and rudimentary, and facial and body hair is absent or decreased. Balding has not been reported. Spermatogenesis is normal if the testes are descended. The clinical, biochemical and molecular genetic analyses of 5alpha-reductase-2 deficiency highlight the significance of DHT in male sexual differentiation and male pathophysiology.

Current and future genetic screening for male infertility

Although much of male infertility is currently unexplained, it is likely that underlying defects in critical genes or entire gene pathways are responsible. Because powerful technologies exist to bypass severe male-factor infertility, improving the diagnosis of genetic infertility is important for the infertile couple, not only to explain the problem but also to inform them of conditions potentially transmissible to offspring.

Finasteride cream in hirsutism

OBJECTIVE

To determine, in a preliminary study, whether women with hirsutism attributable to various causes would benefit from treatment with finasteride cream.

METHODS

Finasteride cream (0.25%) and placebo cream were administered to eight women with various degrees of facial hirsutism. The two creams were used on opposite sides of the face in an area of excessive hair growth. The side chosen for the finasteride cream versus placebo was randomized and blinded. In a 1 cm2 area on each side of the face, hair counts were done every 2 months throughout the 6-month study period. Hair thickness was also measured.

RESULTS

Hair follicles respond to testosterone by the conversion of this androgen to dihydrotestosterone through the action of 5a-reductase. Finasteride partially blocks this enzyme. Because of the easy solubility of this medication through the skin, a cream applied to the area of hair growth would be expected to decrease hirsutism locally. After a 6-month period, mean hair counts decreased significantly from 27.5 to 15.5 (P<0.05) in the finasteride-treated sites but showed no significant change from baseline in the placebo-applied sites. Moreover, the mean thickness of the measured hairs (in hundredths of millimeters) was significantly different between the placebo and finasteride-treated sites (4.33 versus 3.11, respectively; P<0.001).

CONCLUSION

In this study of women with facial hirsutism, topically applied finasteride significantly decreased hair growth and thickness, and no adverse effects were noted.

Identification of missense mutations in the SRD5A2 gene from patients with steroid 5alpha-reductase 2 deficiency

BACKGROUND AND OBJECTIVE

Mutations of the steroid 5alpha-reductase type 2 (SRD5A2) gene in karyotypic males result in a spectrum of external genitalia phenotypes ranging from complete female to nearly complete male. Here we performed genomic DNA analyses from individuals bearing the enzyme deficiency in order to detect the molecular abnormalities.

PATIENTS

Four unrelated 46,XY patients of Mexican origin with ambiguous external genitalia were studied. A fertile, phenotypically normal male was also included.

MEASUREMENTS

Coding sequence abnormalities of the SRD5A2 gene were assessed by exon-specific polymerase chain reaction, single-stranded conformational polymorphism and sequencing analysis.

RESULTS

Five different missense mutations (two of them novel mutations) were identified. Three subjects presented homozygous single base mutations. These were located at exon 2 (G115D), exon 4 (P212R) and exon 5 (R246Q), and such changes have been described previously. The fourth patient was a compound heterozygote who presented two mutations located in exons 1 and 2. We found a hitherto unreported G --> A transition at the second nucleotide of codon 85 in exon 1 (GGC --> GAC), substituting glycine for aspartic acid (G85D). This patient also presented an identical alteration at codon 115 of exon 2, which was carried by his father (G115D). Finally, in another subject who was included originally as a control, we found a C --> A transversion (yet undescribed) at codon 245 in exon 5 (S245Y).

CONCLUSIONS

Four different single base mutations that cause amino acid substitutions were detected in the steroid 5alpha-reductase type 2 gene of affected individuals. One patient and a normal control had two previously undescribed mutations. Although in the latter individual we cannot exclude the possibility that the base change is a genetic polymorphism, the molecular screening of 100 chromosomes suggests strongly that the change at codon 245 does represent a heterozygous mutation. Further studies, including the recreation of the mutations, will help to reveal the biochemical consequences resulting from these changes.

The incidence of intersexuality in children with cryptorchidism and hypospadias: stratification based on gonadal palpability and meatal position

PURPOSE

The combined findings of cryptorchidism and hypospadias often indicate the existence of an intersex state. Testicular maldescent and incomplete tubularization of the urethral plate occur in a spectrum with the severity of the 2 processes likely dependent on the degree of pathophysiology in the androgenic hormonal axis. The incidence of intersexuality in children with undescended testes, hypospadias and otherwise nonambiguous male genitalia has been reported to be 27%. Although the likelihood of genotypic or gonadal ambiguity has previously been associated with meatal position in this population, to our knowledge our study is the first to evaluate the incidence of intersexuality relative to whether the undescended testis is palpable or nonpalpable.

MATERIALS AND METHODS

The database at our hospital was searched for all cases of undescended testes (2,105) and hypospadias (1,057) between 1982 and 1996. Radiographic, histological and karyotypic data were compiled for all patients presenting with both diagnoses. Gonadal palpability (palpable versus nonpalpable) and meatal position (anterior versus mid versus posterior) were recorded and correlated with the likelihood of identifying an intersex condition. Ten boys with a diagnosis of undescended testes subsequent to inguinal hernial repair were excluded from study. Patients with congenital adrenal hyperplasia or complete testicular feminization were also excluded from study due to the clearly female appearance of the external genitalia. Statistical significance was assessed using Fisher's exact test.

RESULTS

We identified 79 patients presenting with undescended testes, hypospadias and a phallus that was believed to be a possible penis. Intersex conditions were identified with nearly equal frequency in the 44 cases of unilateral (30%) and 35 of bilateral (32%) cryptorchidism. In the unilateral undescended testes group patients with a nonpalpable testis were at least 3-fold more likely to have an intersex condition than those with a palpable undescended testis (50 versus 15%, p = 0.02). In the bilateral group patients with 1 or more nonpalpable testes were also nearly 3-fold as likely to have an intersex condition than those with bilateral palpable undescended gonads (47 versus 16%, p = 0.07). Meatal position was graded as anterior in 33% of cases, mid in 25% and posterior in 41% with the more posterior location conferring a significantly greater likelihood of an intersex condition (anterior 2 of 26, mid 1 of 20 and posterior 21 of 33).

CONCLUSIONS

Gonadal palpability is an important predictor of an intersex state in unilateral and bilateral cases of cryptorchidism with hypospadias. Patients with an undescended testis that cannot be palpated are significantly more likely to have an intersex condition than those in whom the undescended testis may be palpated on physical examination. The severity of hypospadias likewise has a strong positive correlation with an intersex state.