Olaf Hiort

Epidemiology and Initial Management of Ambiguous Genitalia at Birth in Germany

Background: In this epidemiological study, we sought to capture the incidence of ambiguous genitalia in neonates and to describe initial management strategies. Methods: We used the registry for rare diseases in pediatrics in Germany to ascertain cases and asked reporting institutions for information on phenotype, laboratory tests, imaging results, diagnosis, initial management and sex assignment. Results: We identified 80 cases within a 2-year study period and calculated an incidence of 2 per 10,000 births with ambiguous genitalia per year in Germany. Prevalence was higher in infants from non-German family background. In more than 50% of all infants a definite diagnosis was lacking even at the age of 6 months. In those cases where the etiology was confirmed, the most common diagnosis was congenital adrenal hyperplasia, followed by androgen insensitivity syndrome and mixed gonadal dysgenesis. Associated malformations were very common, affecting 37.5% of all infants. Sex assignment was female in 46,XY infants with predominately female phenotype and all 46,XX infants. Early surgery was performed in many cases irrespective whether a definite diagnosis had been established or not. Integrated psychosocial care was the exception rather than the rule. Conclusions: Classification and management of ambiguous genitalia at birth remain a challenge for all professionals involved. National and international registries may help to provide a better understanding of the incidence and clinical course of such disorders.

Summary of Consensus Statement on Intersex Disorders and Their Management

Advances in understanding of genetic control of sexual determination and differentiation, improvements in diagnostic testing and surgical genital repair, and the persistent controversies inherent to clinical management were all compelling factors that led to the organization of an international consensus conference. The goals were to acknowledge and discuss the more controversial issues in intersex management, provide management guidelines for intersex patients, and identify and prioritize questions that need additional investigation. This is a summary statement. Advances in molecular genetic causes of abnormal sexual development and heightened awareness of the ethical and patient-advocacy issues mandate reexamination of existing nomenclature for patients with intersex.1 Terminology such as “pseudohermaphroditism” is controversial, potentially pejorative to patients,2 and inherently confusing. Therefore, the term “disorders of sex development” (DSD) is proposed to indicate congenital conditions with atypical development of chromosomal, gonadal, or anatomic sex. Additional rationale for new classification is the need for modern categorization to integrate the modern molecular genetic aspects, to maximize precision when applying definitions and diagnostic labels,3 and to meet the need for psychologically sensitive yet descriptive medical terminology. Nomenclature should be flexible enough to incorporate new information, robust enough to maintain a consistent framework, use descriptive terms, reflect genetic etiology, accommodate phenotypic variation spectrum, and be useful for clinicians, scientists, patients, and families. Hence, we propose a new classification (see “Consensus Statement on Management of Intersex Disorders”4 in this months issue of Pediatrics Electronic Edition ). Three traditionally conceptualized domains of psychosexual development are gender identity (ones self-representation [ie, male or female]), gender role (sexually dimorphic behaviors within the general population, such as toy preferences, aggression, and spatial ability), and sexual orientation (direction[s] of erotic interest). Gender dissatisfaction denotes unhappiness with assigned sex and may result in gender self-reassignment. Psychosexual developmental factors relate to parental psychopathology, parent-child … Address correspondence to Peter A. Lee, MD, PhD, Department of Pediatrics, MC-H085, Penn State College of Medicine, Milton S. Hershey Medical Center, Box 850, 500 University Dr, Hershey, PA 17033-0850. E-mail: plee{at}psu.edu

Phenotypic classification of male pseudohermaphroditism due to steroid 5α‐reductase 2 deficiency

Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5 alpha-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5 alpha-reductase 2 deficiency (SRD). Phenotypes, which were classified according to the severity of the masculinization defect, varied between completely female (SRD type 5), predominantly female (SRD type 4), ambiguous (SRD type 3), predominantly male with micropenis and hypospadias (SRD type 2), and completely male without overt signs of undermasculinization (SRD type 1). T/DHT-ratios were highly increased ( > 50) in the classical syndrome (SRD type 5), but variable in the less severe affected patients (SRD types 1-4) (14-35). Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5 alpha-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5 alpha-reductase 2 deficiency.

The clinical and molecular spectrum of androgen insensitivity syndromes

Androgen insensitivity syndromes (AIS) are due to end-organ resistance to androgenic steroids in males leading to defective virilization of the external genitalia. The phenotype encompasses a wide array of genital ambiguity and may range from completely female to undervirilized but unequivocally male with infertility. This disorder is caused by mutations of the androgen receptor and is an X-linked recessive trait. We have studied 47 patients with AIS and have characterized the underlying molecular abnormality in the androgen receptor gene. Twenty patients had complete AIS and twenty-seven had partial AIS. Of the latter, 11 were of predominantly female phenotypic appearance and gender was assigned accordingly, while 16 were raised as males. Within the group of complete AIS, two patients had gross deletions within the gene, one had a small deletion, and one had an insertion. In the other patients with complete AIS, as well as all individuals with partial AIS, single nucleotide substitutions within the coding region were detected, each leading to an amino acid alteration. Seven codons were involved in more than one mutation in different cases. In addition, in one patient with spinal and bulbar muscular atrophy, an elongation of a glutamine-repeat was characterized. We conclude that mutations in the androgen receptor gene may be present throughout the whole coding region. However, our study provides evidence that several mutational hot spots exist.

Functional assessment and clinical classification of androgen sensitivity in patients with mutations of the androgen receptor gene

Abstract In the genetic male, mutations of the androgen receptor (AR) gene cause phenotypes ranging from female to subfertile male. Binding assays on genital skin fibroblasts and DNA analysis alone provide incomplete information about receptor function. We used the sex hormone-binding globulin (SHBG) response to stanozolol as a measure of AR function and correlated the results with phenotypes which were classified according to the degree of defective masculinization. Of the 34 patients investigated, 9 had complete, and 14 had partial androgen insensitivity syndrome (AIS) with predominantly female, ambiguous, or predominantly male phenotype. Eleven subjects served as controls. Mutations were characterized using polymerase chain reaction-single strand conformation polymorphism analysis and direct DNA sequencing. DNA analysis revealed two major deletions, two minor defects leading to premature stop codons in exon 1, and 19 point mutations in the DNA- and hormone-binding domains of the AR gene. After stanozolol, SHBG remained unchanged in patients with complete AIS (102.0 ± 3.8 [SE]%; range 92.4%–129% of the initial value). The SHBG decrease was diminished in partial AIS with predominantly female (83.8% ± 1.7%; range 81.3%–87.0%), ambiguous (80.4% ± 4.4%, range 68.4%–89.1%), and predominantly male (mean 65.9% ± 4.9%, range 48.6%– 80.8%) phenotypes, and normal in controls (51.4% ± 2.1%, range 35.6%–62.1%). Differences between controls and each AIS group were statistically significant (P< < 0.05 – < 0.0001). A close correlation was found between the degree of undermasculinization (AIS phenotype) and the SHBG response. Conclusions The SHBG test provides functional information about the severity of the receptor defect in vivo and hence adds to the structural information provided by DNA analysis. It detects receptor defects due to mutations within the entire gene, including the DNA-binding domain, and is a rapid, simple, and cost effective procedure. It may provide useful information for the diagnosis and management of affected children.

A Novel Ultrapressure Liquid Chromatography Tandem Mass Spectrometry Method for the Simultaneous Determination of Androstenedione, Testosterone, and Dihydrotestosterone in Pediatric Blood Samples: Age- and Sex-Specific Reference Data

CONTEXT Current immunoassays for analysis of plasma androgens in children have several limitations due to antibody-specific variations of data and normal ranges. Mass spectrometry-based methods are available for individual steroids but need complex sample preparation and report only fragmentary reference data for the pediatric population. OBJECTIVE Our objective was to develop a state of the art sensitive and specific tandem mass spectrometry method for high-throughput simultaneous determination of plasma concentrations of androstenedione (A), testosterone (T), and dihydrotestosterone (DHT) and to report age-, sex-, and pubertal stage-specific reference levels for these steroids in children aged 0-18 yr. SUBJECTS AND METHODS Plasma (100 microl) was mixed with internal standard and extracted by solid-phase extraction. Androgens were measured by ultrapressure liquid chromatography tandem mass spectrometry. Samples of 138 boys and 131 girls with neither signs of endocrine nor systemic disease were considered for the generation of reference data. The following age groups were used: less than 1 wk, 2 wk to 2 months, 3-5 months, 6-11 months, 1-3 yr, 4-6 yr, 7-9 yr, 10-12 yr, 13-15 yr, and over 16 yr. RESULTS Lower quantification limit was 2.9 ng/dl (0.1 nmol/liter) for A, T, and DHT. No relevant interference with other steroids was detected. Reference data for A, T, and DHT are reported as functions of age, sex, pubertal maturation, and testicular volume. CONCLUSION Simplicity, velocity, sensitivity, specificity, and the availability of pediatric reference data allow application of our new method in clinical routine as well as in research settings.

Deletion and Point Mutations of PTHLH Cause Brachydactyly Type E

Autosomal-dominant brachydactyly type E (BDE) is a congenital limb malformation characterized by small hands and feet predominantly as a result of shortened metacarpals and metatarsals. In a large pedigree with BDE, short stature, and learning disabilities, we detected a microdeletion of approximately 900 kb encompassing PTHLH, the gene coding for parathyroid hormone related protein (PTHRP). PTHRP is known to regulate the balance between chondrocyte proliferation and the onset of hypertrophic differentiation during endochondral bone development. Inactivation of Pthrp in mice results in short-limbed dwarfism because of premature differentiation of chondrocyte. On the basis of our initial finding, we tested further individuals with BDE and short stature for mutations in PTHLH. We identified two missense (L44P and L60P), a nonstop (X178WextX( *)54), and a nonsense (K120X) mutation. The missense mutation L60P was tested in chicken micromass culture with the replication-competent avian sarcoma leukosis virus retroviral expression system and was shown to result in a loss of function. Thus, loss-of-function mutations in PTHLH cause BDE with short stature.

The spectrum of phenotypes associated with mutations in steroidogenic factor 1 (SF-1, NR5A1, Ad4BP) includes severe penoscrotal hypospadias in 46,XY males without adrenal insufficiency

Objective Hypospadias is a frequent congenital anomaly but in most cases an underlying cause is not found. Steroidogenic factor 1 (SF-1, NR5A1, Ad4BP) is a key regulator of human sex development and an increasing number of SF-1 (NR5A1) mutations are reported in 46,XY disorders of sex development (DSD). We hypothesized that NR5A1 mutations could be identified in boys with hypospadias. Design and methods Mutational analysis of NR5A1 in 60 individuals with varying degrees of hypospadias from the German DSD network. Results Heterozygous NR5A1 mutations were found in three out of 60 cases. These three individuals represented the most severe end of the spectrum studied as they presented with penoscrotal hypospadias, variable androgenization of the phallus and undescended testes (three out of 20 cases (15%) with this phenotype). Testosterone was low in all three patients and inhibin B/anti-Müllerian hormone (AMH) were low in two patients. Two patients had a clear male gender assignment. Gender re-assignment to male occurred in the third case. Two patients harbored heterozygous nonsense mutations (p.Q107X/WT, p.E11X/WT). One patient had a heterozygous splice site mutation in intron 2 (c.103-3A/WT) predicted to disrupt the main DNA-binding motif. Functional studies of the nonsense mutants showed impaired transcriptional activation of an SF-1-responsive promoter (Cyp11a). To date, adrenal insufficiency has not occurred in any of the patients. Conclusions SF-1 (NR5A1) mutations should be considered in 46,XY individuals with severe (penoscrotal) hypospadias, especially if undescended testes, low testosterone, or low inhibin B/AMH levels are present. SF-1 mutations in milder forms of idiopathic hypospadias are unlikely to be common.

Etiologic classification of severe hypospadias: Implications for prognosis and management

Objective Classification of severe hypospadias employing a broad array of diagnostic tools. Standardization of a diagnostic approach to children with hypospadias. Identification of patients at risk of having malignancies and endocrine problems. Design Retrospective analysis of patients in a single-center study. Subjects Thirty-three patients with severe (scrotal or penoscrotal) hypospadias, aged 1 to 18 years. Methods Clinical assessment, ultrasonography, karyotyping, endocrine evaluation including adrenal steroid concentrations, sex hormone-binding globulin test for androgen sensitivity, human chorionic gonadotropin stimulation with determination of testosterone and dihydrotestosterone concentrations to exclude 5α-reductase deficiency, and molecular genetic analysis of the androgen receptor gene and the 5α-reductase gene. Results In 12 patients the cause was clarified. Diagnoses included Drash syndrome with Wilms tumor in infancy (3 patients), partial androgen msensitivity resulting from androgen receptor mutations (2), true hermaphroditism (2), chromosomal aberration (1), deficiency of antimullerian hormone (1), gonadal dysgenesis (1), partial 5α-reductase deficiency caused by a novel point mutation (1), and XX-male syndrome (1). Twelve patients had associated findings such as cardiac malformations (3 patients), rectal atresia (1), dilation of urinary tract (2), cystinuria (1), and others. Conclusions Patients with severe hypospadias should be submitted to a standardized set of diagnostic procedures in infancy. A stepwise diagnostic study avoids unnecessary, invasive, and expensive testing. A high proportion of classified causes can be expected. Patients at risk of having malignancies or hormonal disorders must remain under close surveillance.

Inherited and de novo androgen receptor gene mutations : investigation of single-case families

OBJECTIVE The objective of this study was to assess somatic and inherited androgen receptor gene mutations in families with only one affected individual. METHODS Molecular genetic analysis of the androgen receptor gene in DNA derived from blood leukocytes from 30 families with single-strand conformation analysis, direct sequencing, and restriction fragment analysis was performed. RESULTS In 22 families the mothers and all investigated grandmothers were heterozygous carriers. However, within the sisters and aunts, both heterozygous carriers and noncarriers were present. In eight families a de novo mutation was characterized. In three of these patients indication for somatic mosaicism was found. CONCLUSIONS De novo mutations occur at a high rate within the androgen receptor gene (8 of 30 = 26.7%); a high proportion (3 of 8) arise after the zygote stage. Thus only direct analysis of the underlying mutation of the androgen receptor gene in the proband and his or her family can provide the basis for genetic counseling.