The coexistence of male pseudohermaphrodites with 17-ketosteroid reductase deficiency and 5 alpha-reductase deficiency within a Turkish kindred

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.

Complexities of gender assignment in 17β-hydroxysteroid dehydrogenase type 3 deficiency: is there a role for early orchiectomy?

Background

17β-Hydroxysteroid dehydrogenase type-3 (17βHSD-3) deficiency is a rare cause of 46,XY disorders of sex development. The enzyme converts androstenedione to testosterone, necessary for masculinization of male genitalia in utero. 17βHSD-3 deficiency is frequently diagnosed late, at puberty, following virilization, with consequent female-to-male gender reassignment in 39-64%. The decision for sex of rearing is difficult, especially if diagnosed in early childhood. Consensus guidelines are equivocal or support male gender assignment. Long-term outcomes data to guide decisions are also lacking; however, in the few cases of early diagnosis and orchiectomy, female gender retention appears more likely.

We report two patients with 17βHSD-3 deficiency, who presented at unusual ages, in whom female gender was chosen. We performed a focused literature review and summary of gender outcomes in 17βHSD-3 deficiency following early orchiectomy.

Cases

Patient A was a phenotypic female who presented at one year of age with bilateral inguinal hernias and external female genitalia. Testes were identified at surgery. The karyotype was 46,XY. She was initially diagnosed with complete androgen insensitivity syndrome; however, androgen receptor mutation analysis was negative. Human chorionic gonadotropin stimulation yielded a low testosterone: androstenedione ratio (0.6, normal >0.8). Genetic testing demonstrated compound heterozygosity for two known mutations of the HSD17B3 gene. She underwent bilateral orchiectomy at two years of age.

Patient B was born with female genitalia and virilized at 13 years of age. She did not seek evaluation until 22 years of age. Her karyotype was 46,XY. She had bilateral inguinal testes and low testosterone: androstenedione ratio (0.3). HSD17B3 gene sequencing showed her to be a compound heterozygote for two known mutations. She identified herself as female and underwent bilateral orchiectomy and estrogen replacement therapy.

Conclusions

These two patients highlight the complexities of diagnosis and management in 17βHSD-3 deficiency. Although existing data are limited, early orchiectomy is likely to result in retention of female gender identity, avoiding the complications related to virilization in adolescence. As such, it is important to pursue a definitive diagnosis to guide clinical decisions, and to have the support and long term follow up with an inter-disciplinary disorders of sex development team.

A novel missense mutation of 5-alpha reductase type 2 gene (SRD5A2) leads to severe male pseudohermaphroditism in a Turkish family

OBJECTIVES

To analyze the steroid 5-alpha reductase type 2 gene (SRD5A2) in 2 siblings with severe male pseudohermaphroditism suspected to have 5-alpha reductase deficiency in a Turkish family.

METHODS

Two female siblings of a family with 7 children were referred to the urology department because of bilateral inguinal masses. The patients had presented after birth with ambiguous genitalia, but no further diagnostic procedures had been performed, and they were raised as girls until the ages of 13 and 15 years. At this time, both had striking ambiguity of the genitalia, with a clitoris-like phallus, severely bifid scrotum, pseudovaginal perineoscrotal hypospadias, a rudimentary prostate, and inguinal testes. Karyotype was 46,XY. Basal and stimulated levels of serum testosterone (T), dihydrotestosterone (DHT), and T/DHT ratio indicated 5-alpha reductase deficiency. Molecular genetic analysis was performed on deoxyribonucleic acid from peripheral blood leukocytes by single-stranded conformational polymorphism analysis and direct sequencing.

RESULTS

Analysis of the SRD5A2 gene revealed a new homozygous missense mutation in exon 2. At codon 123, we identified a GGA to AGA change resulting in a missense amino acid change from glycine to arginine (G123R). Both parents and the 2 healthy sisters and 3 brothers were all heterozygous at codon 123 for the same mutation.

CONCLUSIONS

We report a novel homozygous missense mutation in exon 2 of the 5-alpha reductase type 2 gene that led to severe undervirilization in 2 siblings.

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.

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.

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.

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.

Natural potent androgens: lessons from human genetic models

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase-3 (17 beta-HSD-3) deficiency and 5 alpha-reductase-2 (5 alpha-RD-2) deficiency provides natural human genetic models to elucidate androgen actions. To date, five 17 beta-HSD isozymes have been cloned that catalyse the oxidoreduction of androstenedione and testosterone and dihydrotestosterone (DHT), oestrone and oestradiol. Mutations in the isozyme 17 beta-HSD-3 gene are responsible for male pseudohermaphroditism due to 17 beta-HSD deficiency. The type 3 isozyme preferentially catalyses the reduction of androstenedione to testosterone and is primarily expressed in the testes. Fourteen mutations in the 17 beta-HSD-3 gene have been identified from different ethnic groups. Affected males with the 17 beta-HSD-3 gene defect have normal wolffian structures but ambiguous external genitalia at birth. Many are raised as girls but virilize at the time of puberty and adopt a male gender role. Some develop gynaecomastia at puberty, which appears to be related to the testosterone/oestradiol ratio. Two 5 alpha-reductase (5 alpha-RD) isozymes, types 1 and 2, have been identified, which convert testosterone to the more potent androgen DHT. Mutations in the 5 alpha-RD-2 gene cause male pseudohermaphroditism, and 31 mutations in the 5 alpha-RD-2 gene have been reported from various ethnic groups. Such individuals also have normal wolffian structure but ambiguous external genitalia at birth and are raised as girls. Virilization occurs at puberty, often with a gender role change. The prostate remains infantile and facial hair is decreased. Balding has not been reported.

The identification of 5 alpha-reductase-2 and 17 beta-hydroxysteroid dehydrogenase-3 gene defects in male pseudohermaphrodites from a Turkish kindred

Male pseudohermaphroditism (MPH) is characterized by incomplete differentiation of male genitalia in the presence of testicular tissue. Enzymatic defects involving androgen synthesis or action are causes of MPH. We studied the molecular genetics of a large isolated inbred Turkish kindred with MPH due to either 5 alpha-reductase-2 (SRD5A2) or 17 beta-hydroxysteroid dehydrogenase-3 (17 beta HSD3) gene defects. Using single strand DNA conformational polymorphism analysis and DNA sequencing, a new mutation in exon 5 of SRD5A2 gene was detected in certain male pseudohermaphrodites from this kindred. This single base deletion (adenine) resulted in a frame shift at amino acid position 251 resulting in the addition of 23 amino acids at the carboxyl-terminal of this 254-amino acid isozyme. Transfection expression of the mutant isozyme in CV1 cells showed a complete loss of enzymatic activity in the conversion of [14C]testosterone to dihydrotestosterone, without a change in the messenger ribonucleic acid level compared to that of the wild-type isozyme. Analysis of the 17 beta HSD3 gene in other male pseudohermaphrodites from this kindred revealed a single point mutation (G-->A) at the boundary between intron 8 and exon 9, disrupting the splice acceptor site of exon 9. In this kindred, in addition to the identification of male pseudohermaphrodites with either a homozygous SRD5A2 or 17 beta HSD3 gene defect, other male pseudohermaphrodites were found to be genetically more complex: e.g. homozygous for the SRD5A2 defect and heterozygous for the 17 beta HSD3 defect, or homozygous for the 17 beta HSD3 defect and heterozygous for the SRD5A2 defect. Also, phenotypically normal carriers were identified with either one or both gene defects. Homozygous male pseudohermaphrodites with SRD5A2 or 17 beta HSD3 gene defects were phenotypically distinguishable by the presence of mild gynecomastia in the latter. Hormone data were consistent with the particular homozygous gene defect. In summary, we show 1) the novel existence of two gene defects, SRD5A2 and 17 beta HSD3, each causing MPH within a large isolated Turkish kindred; 2) that the two defects segregate independently and may be inherited from two different progenitors; and 3) analysis of a new mutation in exon 5 of SRD5A2 gene, supporting the functional importance of the carboxyl-terminal of 5 alpha-reductase-2 isozyme.

Role of 5 alpha-reductase in health and disease

The mechanism of androgen action varies in different tissues, but in the majority of androgen target tissues either testosterone or 5 alpha-dihydrotestosterone (DHT) binds to a specific androgen receptor to form a complex that can regulate gene expression. Testosterone is metabolized to DHT by the enzyme 5 alpha-reductase. The autosomal recessive genetic disorder of 5 alpha-reductase deficiency has clearly shown that the requirement for DHT formation varies with different tissues. In this syndrome genetic males contain normal male internal structures including testes, but exhibit ambiguous or female external genitalia at birth; at puberty they undergo partial virilization which includes development of a male gender identity even if brought up as females. Their development suggests that testosterone itself is able to stimulate psychosexual behaviour, development of the embryonic wolffian duct, muscle development, voice deepening, spermatogenesis, and axillary and pubic hair growth; DHT seems to be essential for prostate development and growth, the development of the external genitalia and male patterns of facial and body hair growth or male-pattern baldness. How different hormones operate to regulate genes via the same receptor is currently unknown, but appears to involve cell-specific factors. The 5-alpha-reductase enzyme has proved difficult to isolate biochemically, but recently at least two human isoenzymes have been identified using molecular biological methods. All the various 5 alpha-reductase-deficient kindreds have been shown to have mutations in 5 alpha-reductase 2, the predominant form in the prostate. The biological role of 5 alpha-reductase 1 has not yet been ascertained, but at present it cannot be ruled out that some of the actions ascribed to testosterone are indeed in cells producing DHT via this enzyme. The activity of 5 alpha-reductase is also implicated in benign prostatic hypertrophy, hirsutism and possibly male-pattern baldness; recent evidence discounts the role of 5 alpha reductase 2 in sebaceous glands and acne. Specific inhibitors of both enzymes are now available and finasteride, a 5 alpha-reductase 2 inhibitor, has been used successfully in clinical trials of benign prostatic hypertrophy. Knowledge of 5 alpha-reductase is expanding dramatically at the moment with the application of molecular biological methods. The advent of antibodies to the isoenzymes should herald further understanding of their biological and clinical roles.

Genetic diseases of steroid metabolism

All major classes of biologically active steroid hormones (progestins, mineralocorticoids, glucocorticoids, and sex steroids) are synthesized from cholesterol through 11 different bioconversions. With the exception of 5 alpha-reductase, all the enzymes mediating these reactions fall into two classes, cytochromes P450 and short-chain dehydrogenases. Cytochromes P450 are heme-containing membrane-bound proteins with molecular weights of approximately 50,000 that utilize molecular oxygen and electrons from NADPH-dependent accessory proteins to hydroxylate substrates. Short-chain dehydrogenases have molecular weights of 30,000-40,000, have tyrosine and lysine residues at the active site, and remove a hydride from the substrate, transferring the electrons of the hydride to NAD+ or NADP+. In most cases, this reaction is reversible so that the dehydrogenase can also function as a reductase under appropriate conditions. Inherited disorders in enzymes required for steroid biosynthesis have varying effects. Defects that prevent cortisol from being synthesized are referred to collectively as congenital adrenal hyperplasia. Because the enzymes required for cortisol biosynthesis in the adrenal cortex are in many cases required for the synthesis of mineralocorticoids and/or sex steroids, these classes of steroids may also not be synthesized normally. Thus, cholesterol desmolase and 3 beta-hydroxysteroid dehydrogenase deficiencies affect synthesis of all classes of steroids in both the adrenals and gonads. Steroid 21-hydroxylase deficiency, the most common cause (> 90% of cases) of congenital adrenal hyperplasia, can affect both mineralocorticoid and glucocorticoid synthesis, but androgen secretion is usually abnormally high due to shunting of accumulated precursors into this pathway. Excessive secretion of androgens and mineralocorticoids occurs in 11 beta-hydroxylase deficiency (the second most frequent form of congenital adrenal hyperplasia). Mineralocorticoid excess is also seen in 17 alpha-hydroxylase deficiency, but in this disorder sex steroid synthesis is defective. All defects that affect estrogen synthesis (deficiencies of cholesterol desmolase, 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, aromatase, and 17 beta-hydroxysteroid dehydrogenase) are very rare, suggesting that the inability to synthesize placental estrogens may adversely affect fetal survival. A number of enzymes are expressed at sites of steroid action and regulate the amount of active steroid available to steroid receptors. Steroid 5 alpha-reductase converts testosterone to the more active dihydrotestosterone. Deficiency of this activity leads to incomplete development of male genitalia; 17 beta-hydroxysteroid dehydrogenase deficiency has similar phenotypic effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgen effects on vocal muscle structure in a teleost fish with inter- and intra-sexual dimorphism

The plainfin midshipman fish Porichthys notatus has both inter- and intra-sexual dimorphism in the sound-producing (vocal or sonic) muscles attached to the swimbladder wall. The "Type I" and "Type II" male morphs differ in that dramatic structural changes related to sexual maturity occur in the mass, the area of mitochondria-filled sarcoplasm, and the myofiber number of the sonic muscles of Type I males, but not in those of Type II males (nor of females). Androgen implantation for 9 weeks markedly increased the relative sonic muscle size in juvenile males, juvenile females, and Type II males, whereas estradiol or cholesterol treatment did not. The principal androgen effect on myofiber structure was an increase in the area of mitochondria-filled sarcoplasm. The ratio of sarcoplasm area to myofibril area (Sr/Mf) increased by 1.4- to 2-fold in myofibers of all androgen-treated groups, with the greatest structural change occurring in juvenile males. When androgen implants were removed from juvenile males, the muscle mass and Sr/Mf ratio reverted toward the unimplanted juvenile phenotype. Total fiber number in sonic muscle increased significantly in juvenile males following androgen implantation but did not detectably change in juvenile females or Type II males. These results suggest: 1) sonic muscle in Porichthys notatus is an androgen target tissue, 2) fiber structure and fiber number are androgen-sensitive features, and 3) there exist sex- and morph-specific patterns of sonic muscle responsiveness to androgen implants.

Steroid 17β-hydroxysteroid dehydrogenase deficiency in man: an inherited form of male pseudohermaphroditism

Sixty-eight males with testicular 17β-hydroxysteroid dehydrogenase deficiency (17β-HSD) were identified among a highly inbred Arab population in Israel, and 45 studied over the last 15 years. The founders of this defect originated in the mountainous region of present Lebanon and Syria, but most of the families now live in Jerusalem, Hebron, the Tel-Aviv area, and in particular Gaza, where the frequency of affected males is estimated at 1 in 100 to 150. Affected individuals (46,XY) are born with ambiguity of the genitalia and reared as females until puberty. Thereafter marked virilization occurs, leading in many cases to the spontaneous adoption of a male gender role. Adults develop a male habitus with abundant body hair and beard, and the phallus and testes enlarge to adult proportions. Gender reassignment was possible only when enough erectile tissue was present at birth and developed into a normal size penis with systemic testosterone. male genitoplasty was performed in 15 children and 8 post-pubertal patients, and female genitoplasty in 2 children and 4 post-pubertal patients. In adults the defect is characterized by markedly increased concentrations of 4-androstendione (4-A) with borderline low to normal testosterone (T) levels, and a high 4-A/T ratio. Dihydrotestosterone (DHT) concentrations were either moderately decreased, normal, or high, and dehydroepiandrosterone levels were high. The estrogen pathway was also impaired, even though both estrone and estradiol-17β levels were elevated. Children had low basal levels of all androgens, but the defect could be demonstrated after prolonged stimulation with human chorionic gonadotropin. LH and FSH levels were very high after puberty, and normal in childhood. However, an over-response to gonadotropin-releasing hormone was found at all ages. Studies in testicular tissue revealed various abnormalities in steroid metabolism. Tissue from pre-pubertal patients metabolized progesterone (P) only to 4-A, while tissue from post-pubertal patients metabolized P to 16α- and 16β-hydroxyprogesterone (5.4- to 10.3-fold greater production), 17α-hydroxyprogesterone (5.4- to 8-fold smaller production), 4-A and T. 4-A was also metabolized to T, indicating that 17β-HSD was no longer deficient. Flow studies with equimolar concentrations of [¹⁴C]P and [³H]pregnenolone showed that the 5-ene pathway was the preferential one for androgen biosynthesis. Both in vivo and in vitro studies indicate that the severity of testicular 17β-HSD deficiency changes with age. Whereas the enzyme activity is absent in childhood, there is a progressive restoration after puberty. Androgen production increases progressively to normal so that T and DHT concentrations are sufficiently high to gradually induce somatic and genital virilization, thus enabling an adequate male gender function.

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

We report a cluster of male pseudohermaphrodites from the Simbari Anga linguistic group in the Eastern Highlands of Papua New Guinea. These subjects are born with a rudimentary clitoral-like penis and pseudovaginal perineoscrotal hypospadias. At puberty, the penis enlarges with concurrent growth of pubic and axillary hair and significant muscular development. There is significant facial hair, but it is less than that of their normal male siblings or other male relatives. Plasma collected from four adult subjects revealed elevated plasma testosterone levels, low to low normal dihydrotestosterone levels, and elevated testosterone/dihydrotestosterone ratios. All subjects had high urinary aetiocholanolone/androsterone ratios, and C19 and C21 5 beta/5 alpha metabolite ratios. Decreased 5 alpha-reductase activity was demonstrated in fibroblasts cultured from genital skin. The data indicate a phenotypic and biochemical profile similar to patients studied in the Dominican Republic, except for a greater abundance of facial and body hair. The phenotypic variability, as pertains to facial and body hair, may be related to differences in familial expression, as well as the degree of enzyme deficiency. Infants, thought to be females at birth, were reared as girls until puberty in a society practising one of the strictest gender segregations known. At puberty, these 'girls' were discovered to be boys, and a switch of gender roles was instituted. Recently, however, some Muniri, Dunkwi and northern Simbari hamlets recognize these individuals as male in infancy and rear them as boys, calling them 'kwalatmala' to distinguish them from normal males, accepting them as an intersex destined to occupy male adult roles.