Defects of the Testosterone Biosynthetic Pathway in Boys With Hypospadias

Quantification of the Androgen and Estrogen Receptors in the Penile Tissues of Hypospadias in Comparison with Normal Children

INTRODUCTION

Hypospadias is a common congenital abnormality typified by a proximally placed ectopic urethral meatus along the ventral surface of the penis. Androgen receptor (AR) and estrogen receptor (ER) expression in the hypospadias tissues may be altered in hypospadias.

METHODOLOGY

We evaluated by immunohistochemistry the AR and ER expression in 75 tissues from hypospadias repair, and compared this expression to that of tissue from 75 patients undergoing circumcision. We also compared the intensity of AR and ER expression between different severities of hypospadias.

RESULTS

AR quantitative grading score decreased with severity of hypospadias, while the ER score increased as the hypospadias worsened, which was statistically significant (p-value <0.05).

CONCLUSION

The penile tissue AR expression is decreased and ER expression is increased with increasing severity of hypospadias.

Preliminary Reference Interval for 5-Alpha Reductase in Normal Male Children and Its Association with Hypospadias

Background

5-alpha reductase (5-AR) enzyme is responsible for conversion of testosterone to dihydrotestosterone (DHT) in humans, which subserves various functions. The aim of the study was to establish a normal reference interval (RI) for blood levels of the enzyme 5-AR.

Methods

We conducted a prospective study on 150 boys, 75 of whom underwent circumcision for various benign conditions or for religious reasons (Group A/controls) and 75 suffering from hypospadias of variable severity (Group B/cases). The plasma levels of 5-AR were measured by enzyme-linked immunosorbent assay (ELISA) in all 150 boys and correlated with the severity of hypospadias.

Results

The 5-AR levels in Group A ranged from 14.6 to 17.3 ng/mL. The enzyme levels decreased in value with increasing severity of hypospadias in Group B (P-value &lt;0.01 - statistically significant). The levels of the enzyme in this group ranged from 0.6 ng/mL (in the most severe variety of hypospadias) to 11.5 ng/mL (mild variety of hypospadias).

Conclusions

There is no record of RI values of 5-AR in the literature. The RI of 5-AR needs to be determined by conducting more studies globally. Its levels falls considerably with clinical severity of hypospadias, reinforcing the importance of the enzyme in the development of male external genitalia.

Androgen Receptor Expression in Hypospadias

Introduction:

The exact mechanism behind the development of hypospadias is unclear. Research studies on androgen receptor (AR) expression are controversial with results stating all possible outcomes – AR elevated, similar, or reduced when compared to normal.

Aims:

The aim is to study the AR expression and hormone levels in hypospadias patients and compare them with children having normal genitalia.

Methods:

Group 1 (controls) involved patients who underwent circumcision for phimosis while Group 2 involved hypospadias patients who did not receive any preoperative testosterone. Preoperative hormonal assay included luteinizing hormone, follicle-stimulating hormone, and free testosterone levels in all the patients. The foreskin specimen was analyzed for AR expression using immunohistochemistry (anti-AR antibody PathnSitu, clone R441, 1/100 dilution). AR staining was expressed as H score. The H score was calculated by multiplying the intensity of staining and the percentage of stained cells showing cytoplasmic positivity at high power (×40).

Results:

There were 27 patients in Group 1 while 16 in Group 2 (distal 10; proximal 6).There was no significant difference in the age distribution. The mean H score was significantly higher (189.5) in hypospadias patients compared to controls (97.5) and was significantly higher in proximal (220) compared to distal (159) hypospadias. There was no significant difference in hormone levels between groups.

Conclusion:

AR expression was significantly elevated in hypospadias patients. It was higher in proximal compared to distal hypospadias, probably due to end-organ overexpression. Further larger trials are likely to through light into this controversial subject.

Perspectives in Pediatric Pathology, Chapter 6. Male Undermasculinization

Normal male development requires three conditions: (1) adequate differentiation of the fetal testis; (2) synthesis and secretion of testicular hormones; and (3) effective action of these hormones on target organs. This requires the combined action of the inhibitory anti-müllerian hormone (AMH, secreted by Sertoli cells) to block the development of the uterus and fallopian tubes from the müllerian duct, together with the trophic stimulus of testosterone (a Leydig cell product), which leads to virilization of the wolffian ducts. Additionally, the development of external genitalia depends on the conversion of testosterone to dihydrotestosterone by the enzyme 5-α-reductase. Failure of any of these mechanisms leads to deficient virilization or the so-called "male pseudohermaphroditism" syndromes.

Epidemiology of male genital abnormalities: a population study

BACKGROUND

We conducted genital health wellness screens in male kindergarten children between the ages of 3 and 6 years to assess the incidence of congenital abnormalities and their treatment.

METHODS

We performed genital examinations on 2241 male children in 8 kindergartens. We screened for 4 conditions: phimosis, hypospadias, cryptorchidism, and hydrocele/hernia. We assessed the incidence of these conditions and the effectiveness or lack of their treatment.

RESULTS

Among this sample, 55.5% children aged 3 to 4 years and 44.1% aged 5 to 6 years were found to have persistent phimosis. The circumcision rate, excluding those performed in conjunction with hypospadias repair, was 2.8%, but it carried a 3.2% complication rate. There was a lower incidence of hypospadias and cryptorchidism than reported in the literature at 0.2% and 0.4%, respectively. Our hypospadias repair rate was 60%, with a success rate of 66.7%. Our cryptorchidism repair rate was only 25%, and all repairs were performed above the age of 5 years. Incidence of hydrocele and hernias was 1.2%, and our treatment rate was 46.2%. Finally, we found high incidence of keloid formation, 73.3%, associated with inguinal incision.

CONCLUSIONS

There was high prevalence of phimosis in Chinese boys, a natural physiologic condition, up to age 6. There appeared to be lower incidences of hypospadias and cryptorchidism in our screened population. However, there were opportunities for us to improve the diagnosis and treatment of these 2 conditions. Our hydrocele/hernia incidence was on par with literature, but we had a lower treatment rate. Finally, we found a high incidence of keloid formation associated with inguinal incision.

Aetiology of hypospadias: a systematic review of genes and environment

BACKGROUND

Hypospadias is a common congenital malformation of the male external genitalia. Most cases have an unknown aetiology, which is probably a mix of monogenic and multifactorial forms, implicating both genes and environmental factors. This review summarizes current knowledge about the aetiology of hypospadias.

METHODS

Pubmed was used to identify studies on hypospadias aetiology published between January 1995 and February 2011. Reference lists of the selected manuscripts were also searched to identify additional studies, including those published before 1995.

RESULTS

The search provided 922 articles and 169 articles were selected for this review. Studies screening groups of patients with hypospadias for single gene defects found mutations in WT1, SF1, BMP4, BMP7, HOXA4, HOXB6, FGF8, FGFR2, AR, HSD3B2, SRD5A2, ATF3, MAMLD1, MID1 and BNC2. However, most investigators are convinced that single mutations do not cause the majority of isolated hypospadias cases. Indeed, associations were found with polymorphisms in FGF8, FGFR2, AR, HSD17B3, SRD5A2, ESR1, ESR2, ATF3, MAMLD1, DGKK, MID1, CYP1A1, GSTM1 and GSTT1. In addition, gene expression studies indentified CTGF, CYR61 and EGF as candidate genes. Environmental factors consistently implicated in hypospadias are low birthweight, maternal hypertension and pre-eclampsia, suggesting that placental insufficiency may play an important role in hypospadias aetiology. Exogenous endocrine-disrupting chemicals have the potential to induce hypospadias but it is unclear whether human exposure is high enough to exert this effect. Other environmental factors have also been associated with hypospadias but, for most, the results are inconsistent.

CONCLUSIONS

Although a number of contributors to the aetiology of hypospadias have been identified, the majority of risk factors remain unknown.

Polymorphisms in the P450 c17 (17-hydroxylase/17, 20-Lyase) gene: association with estradiol and testosterone concentration in hypospadias

OBJECTIVE

To investigate the association of CYP17 polymorphism with 17β-estradiol (E2) and testosterone (T) concentration in hypospadias.

METHODS

Two-hundred twenty-three boys (91 with hypospadias and 132 age-matched controls) were included in the study. CYP17 polymorphism was evaluated using the polymerase chain reaction-restriction fragment length polymorphism method, whereas T and E2 levels were estimated in serum by enzyme-linked immunosorbent assay. Association between CYP17 genotypes and 17β-E2, T, and their ratio (E2/T) was analyzed by analysis of variance followed by Tukey's test. 17β-E2, T, and E2/T ratio was also compared among the different degrees of hypospadias, as well as in controls, by unpaired Student's t-test.

RESULTS

Significantly low levels of T were observed in severe-degree hypospadias (n = 14; mean ± SD = 1.01 ± 0.57) compared with mild cases (n = 77; mean ± SD = 1.93 ± 1.40) and controls (mean ± SD = 3.32 ± 2.06) (P <.05). E2/T ratio was also significantly higher in hypospadias cases (5.36 ± 3.55) compared with controls (2.21 ± 2.52). Heterozygous variants (A1/A2) of CYP17 were present in higher frequency (OR = 0.96; 95% CI = .518-1.770) and homozygous (A2) variants were less frequently found in hypospadias (OR = 0.87; 95% CI = .363-2.077), but results were insignificant. No association between 17β-E2 and T with different CYP17 genotypes was observed.

CONCLUSION

Our study suggests that, although polymorphism in CYP17 gene may not be associated with 17β-E2 and T concentrations in hypospadias cases, low levels of T and higher E2/T ratio might possibly act as risk factors for hypospadias.

Genital reconstruction

Genital reconstruction is necessary in various types of congenital malformations. Although various surgical procedures may be used depending on the anomaly, the basic principles are the same. Three groups of pathology are discussed: hypospadias, ambiguous genitalia and exstrophy-epispadias complex. Progress continues to be made in modifying older techniques and creating new ones. Some investigators have focused on pain control and dressing materials. There is still much work to be done in this challenging area.

Cryptorchidism and hypospadias

PURPOSE

We quantified the burden of cryptorchidism and hypospadias in the United States by identifying trends in the use of health care resources and estimating the economic impact of the disease.

MATERIALS AND METHODS

The analytical methods used to generate these results were described previously.

RESULTS

Cryptorchidism is managed almost exclusively in the outpatient setting and insufficient data were available on inpatient health care use. Annual inpatient hospitalizations for hypospadias decreased by 75% between 1994 and 2000 from 2,669 (2.2/100,000 children) to 849 (0.6/100,000). Between 1992 and 2000 there were 611,647 physician office visits (96/100,000 per year) with undescended testis listed as the primary diagnosis. The rate of physician office visits for hypospadias by commercially insured boys younger than 3 years increased significantly from 429/100,000 in 1994 to 655/100,000 in 2002. The annualized rate of 18/100,000 in 1994 to 1996 remained relatively constant during these 3 years. Orchiopexy rates were highest in 0 to 2-year-old children, as generally recommended, but a substantial minority of these procedures was done in 3 to 10-year-old children. Geographic variation was noted with higher ambulatory surgery rates in the Northeast and Midwest than in the South and West. Data on commercially insured boys younger than 3 years revealed a 1.5-fold overall increase in the rate of hypospadias surgery from 321/100,000 in 1994 to 468/100,000 in 2002, reflecting the known increase in hypospadias incidence in the United States during the late 1990 s.

CONCLUSIONS

Average cost per hospitalization for hypospadias exceeded $5,389 with costs per case higher in children 3 years or older, although there were more cases in children younger than 3 years. The cost per case of hypospadias was higher in the Northeast and South than in the other regions. Data on cryptorchidism are too sparse to provide insights into its downstream economic costs.

The valine allele of the V89L polymorphism in the 5-alpha-reductase gene confers a reduced risk for hypospadias

CONTEXT

Hypospadias is one of the most common malformations in man, with an incidence of 1:300 in newborn boys. No gene has been identified that causes isolated hypospadias, but the androgenic influence is important during male genital development.

OBJECTIVE

A key enzyme for the androgenic function is steroid 5-alpha-reductase (SRD5A2). The V89L polymorphism in the SRD5A2 gene has been studied and found to be of functional importance. The leucine version of the enzyme is 30% less efficient than the valine variant. DESIGN, SETTING, PATIENTS, AND RESULTS: We have genotyped 158 hypospadias cases and 96 unaffected controls for this polymorphism and found a significant negative association for the V89 allele in hypospadias (odds ratio, 0.24; 95% confidence interval, 0.14-0.41 for homozygous individuals). This indicates that a fully functional 5-alpha-reductase enzyme (homozygous for V89) protects the male urethral development. This association is shown regardless of heredity, ethnicity, and severity of phenotype. We have also sequenced a selected material of 37 sporadic cases of more severe hypospadias for mutations in the androgen receptor AR, SRD5A2, and 17beta-hydroxysteroid dehydrogenase HSD17B3 genes and found only two previously described mutations, one in the AR and one in the SRD5A2 gene.

CONCLUSION

This finding is in accordance with the assumption that functional polymorphisms may play an important role in complex disorders such as hypospadias when several genes as well as environmental factors contribute to the etiology.

Idiopathic male pseudohermaphroditism: variations in presentation and management

Male pseudohermaphroditism (MPH) is the abnormal development of genitalia in an individual with a 46,XY chromosome complement and testicular tissue. The etiology of MPH is unknown in most cases, which are defined as idiopathic.

OBJECTIVE

To analyze the data for cases of idiopathic MPH.

PATIENTS AND METHODS

A retrospective study of 29 patients with idiopathic MPH and no uterus.

RESULTS

Four patients had a family history of abnormal sexual development and five had low birth weight. The initial manifestations were sexual ambiguity (26), microphallus and hypospadias (2), and primary amenorrhea (1). Basal and/or stimulated testosterone concentrations showed insufficient testosterone secretion in three patients. Genitography showed a vagina in 13 patients. Male genitoplasties were performed on 21 out of the 24 patients reared as males and female genitoplasties on five patients. Histological studies of the gonads of these showed streak gonads in one, normal gonads in one and signs of testicular dysgenesis in three others. Molecular studies on the SRY gene (17) showed no mutation.

CONCLUSIONS

Idiopathic male pseudohermaphroditism is a heterogeneous condition, even within families with a history of this condition. We propose a set of guidelines for the management of these patients.

Hypospadias surgery: when, what and by whom?

Hypospadias is repaired by paediatric surgeons, paediatric urologists, adult reconstructive urologists and plastic surgeons. This review is unique in representing all four specialities, to provide a unified policy on the management of hypospadias. The surgeon of whichever speciality should have a dedicated interest in this challenging work, ideally having an annual volume of at least 40-50 cases. The ideal time for primary repair is at 6-12 months old, although when this is not practicable there is another opportunity at 3-4 years old. A surgical protocol is presented which emphasises both functional and cosmetic refinement. Using a logical progression of a very few related procedures allows the reliable correction of almost any hypospadias deformity. A one-stage repair is used when the urethral plate does not require transection and its axial integrity can be maintained. Occasionally, when the plate is of adequate width and depth, it can be tubularized directly using the second stage of the two-stage repair. When (usually) the urethral plate is not adequately developed and requires augmentation before it can be tubularized, then that second-stage procedure is modified by adding a dorsal releasing incision +/- a graft (alias Snodgrass and 'Snodgraft' procedures). The two-stage repair offers the most reliable and refined solution for those patients who require transection of the urethral plate and a full circumferential substitution urethroplasty. From available evidence this protocol combines excellent function and cosmesis with optimum reliability. Nevertheless, it would be complacent to assume that these gratifying results will be maintained into adult life. We therefore recommend that there is still a need for active follow-up through to genital maturity.

Cytogenetics and etiology of ambiguous genitalia in 120 pediatric patients

BACKGROUND

A newborn with ambiguous genitalia needs prompt evaluation to detect life-threatening conditions (e.g., salt-losing crisis in congenital adrenal hyperplasia [CAH]) and gender assignment. Sex assignment in these children continues to be a challenging diagnostic and therapeutic problem. We studied the causes and characteristics of ambiguous genitalia in children who were referred to a cytogenetic laboratory.

PATIENTS AND METHODS

We retrospectively reviewed a total of 120 medical records of patients with a primary indication of ambiguous genitalia that were referred to the cytogenetic lab for karyotyping during the period of 1989 to 1999. Diagnosis was based on a clinical impression from the primary physician, who was primarily a staff pediatrician, endocrinologist and/or pediatric urologist.

RESULTS

CAH was the underlying cause of ambiguous genitalia in 41 of 63 patients with ambiguity due to endocrine causes; 39 of these patients showed a 46,XX karyotype and 2 cases were 46,XY (both the 46,XY patients had 3 beta-hydroxylase deficiency). In 57 patients, ambiguous genitalia were due to congenital developmental defects. The most common endocrine case of ambiguous genitalia was 21-OH deficiency. Seven patients were classified as idiopathic with six showing the 46,XY and one the 46,XX karyotype. Gender was reassigned at birth or at diagnosis in 15 patients.

CONCLUSION

The etiology of ambiguous genitalia is variable. The physician managing these families could minimize the trauma of having a child with unidentified sex by providing appropriate genetic counseling so that the parents can make an early decision. Prenatal DNA testing in at-risk families should be considered and appropriate therapy offered to minimize or prevent genital ambiguity.

Hypospadias in the neonate

Hypospadias is a common developmental disorder of the urogenital tract, occurring in approximately 1 in 125 live male births. Defined as an atypical urethral opening anywhere along the shaft of the penis, scrotum, or perineum, hypospadias is often associated with a deficient prepuce and chordee. Hypospadias usually occurs as an isolated defect, but can be part of a recognized syndrome or associated with other genital anomalies. The etiology of nonsyndromic hypospadias is unknown, and is believed to be multifactorial. Recent studies have implicated factors such as familial inheritance, low birth weight, assisted reproductive technology, advanced maternal age, paternal subfertility, and endocrine-disrupting chemicals in the pathogenesis of hypospadias. Infants with hypospadias should not undergo circumcision. Currently, most infants with hypospadias undergo surgical reconstruction between 4 and 8 months of age. Parents of a newborn with hypospadias may be anxious and have many questions about their infant's condition. They should be given the opportunity to speak to a pediatric urologist as early as possible. This article provides a guide to the embryologic origins of hypospadias and a photographic atlas to aid bedside clinicians in identifying the spectrum of hypospadias in the newborn.

Endocrine abnormalities in boys with hypospadias

The multifactorial etiology of hypospadias is becoming more clearly defined with ongoing investigation. Endogenous endocrine abnormalities identified so far include testosterone biosynthesis defects, 5alpha-reductase type 2 mutations, and androgen receptor mutations (the rarest cause, even in cases of severe hypospadias). Other significant risk factors include IVF (because of progesterone administration or endocrine abnormalities associated with infertility) and environmental agents that can potentially cause testicular dysgenesis, disrupt the male androgen axis, and disturb normal male genital embryology (Table 6). [table; see text] It also seems that the incidence of hypospadias is increasing, both in the United States and in Europe--which may be due to better medical care for those with genital abnormalities and/or infertility problems, as well as environmental endocrine disruptors. Hypospadias is a physical manifestation that may be a consequence of numerous physiological aberrations, and our ability to understand and to potentially prevent this congenital malformation will require a significant amount of additional work. Our challenge for the future remains to identify the various etiologies, provide prenatal counseling for affected families with a history of hypospadias, and minimize or eliminate exposure to environmental agents that may contribute to this problem. Perhaps one day we will be able to offer prenatal therapy to prevent hypospadias when the risk for this birth defect seems high. How might this be possible? Consider the modern management of a family with a child born with the adrenogenital syndrome, another endocrine derangement that can cause abnormal genital development. In this situation, dexamethasone can be administered to the mother in subsequent pregnancies to prevent fetal virilization until the sex of the fetus can be determined or adrenal enzyme mutations can be excluded. Perhaps in the future a similar approach will be taken for those families with strong risk factors for hypospadias.

How sexually dimorphic are we? Review and synthesis

The belief that Homo sapiens is absolutely dimorphic with the respect to sex chromosome composition, gonadal structure, hormone levels, and the structure of the internal genital duct systems and external genitalia, derives from the platonic ideal that for each sex there is a single, universally correct developmental pathway and outcome. We surveyed the medical literature from 1955 to the present for studies of the frequency of deviation from the ideal male or female. We conclude that this frequency may be as high as 2% of live births. The frequency of individuals receiving "corrective" genital surgery, however, probably runs between 1 and 2 per 1,000 live births (0.1-0.2%). Am. J. Hum. Biol. 12:151-166, 2000. Copyright 2000 Wiley-Liss, Inc.

How sexually dimorphic are we? Review and synthesis

The belief that Homo sapiens is absolutely dimorphic with the respect to sex chromosome composition, gonadal structure, hormone levels, and the structure of the internal genital duct systems and external genitalia, derives from the platonic ideal that for each sex there is a single, universally correct developmental pathway and outcome. We surveyed the medical literature from 1955 to the present for studies of the frequency of deviation from the ideal male or female. We conclude that this frequency may be as high as 2% of live births. The frequency of individuals receiving "corrective" genital surgery, however, probably runs between 1 and 2 per 1,000 live births (0.1-0.2%). Am. J. Hum. Biol. 12:151-166, 2000. Copyright 2000 Wiley-Liss, Inc.

Hypospadias

The incidence of hypospadias is increasing. Decreased androgen sensitivity, 5alpha-reductase deficiency and chromosomal abnormalities are causes of the disease. Nonirritant suture material, coverage of the urethral reconstruction by additional tissue and perioperative care positively influence the outcome. Complication rates after repair of distal hypospadias are low. For severe hypospadias staged procedures provide good results. Buccal mucosa is promising for initial repair and repeat cases. Psychosocial function in patients with severe hypospadias is normal.