Prevalence of endocrine and genetic abnormalities in boys evaluated systematically for a disorder of sex development

Effects of Sex Hormones on Vascular Reactivity in Boys With Hypospadias

BACKGROUND

Arteries from boys with hypospadias demonstrate hypercontractility and impaired vasorelaxation. The role of sex hormones in these responses in unclear.

AIMS

We compared effects of sex steroids on vascular reactivity in healthy boys and boys with hypospadias.

METHODS

Excess foreskin tissue was obtained from 11 boys undergoing hypospadias repair (cases) and 12 undergoing routine circumcision (controls) (median age [range], 1.5 [1.2-2.7] years) and small resistance arteries were isolated. Vessels were mounted on wire myographs and vascular reactivity was assessed in the absence/presence of 17β-estradiol, dihydrotestosterone (DHT), and testosterone.

RESULTS

In controls, testosterone and 17β-estradiol increased contraction (percent of maximum contraction [Emax]: 83.74 basal vs 125.4 after testosterone, P < .0002; and 83.74 vs 110.2 after estradiol, P = .02). 17β-estradiol reduced vasorelaxation in arteries from controls (Emax: 10.6 vs 15.6 to acetylcholine, P < .0001; and Emax: 14.6 vs 20.5 to sodium nitroprusside, P < .0001). In hypospadias, testosterone (Emax: 137.9 vs 107.2, P = .01) and 17β-estradiol (Emax: 156.9 vs 23.6, P < .0001) reduced contraction. Androgens, but not 17β-estradiol, increased endothelium-dependent and endothelium-independent vasorelaxation in cases (Emax: 77.3 vs 51.7 with testosterone, P = .02; and vs 48.2 with DHT to acetylcholine, P = .0001; Emax: 43.0 vs 39.5 with testosterone, P = .02; and 39.6 vs 37.5 with DHT to sodium nitroprusside, P = .04).

CONCLUSION

In healthy boys, testosterone and 17β-estradiol promote a vasoconstrictor phenotype, whereas in boys with hypospadias, these sex hormones reduce vasoconstriction, with androgens promoting vasorelaxation. Differences in baseline artery function may therefore be sex hormone-independent and the impact of early-life variations in androgen exposure on vascular function needs further study.

Gonadal Function in Boys with Bilateral Undescended Testes

Background

Bilateral undescended testes (BUDT) may be a marker of an underlying condition that affects sex development or maturation.

Aims

To describe the extent of gonadal dysfunction in cases of BUDT who had systematic endocrine and genetic evaluation at a single tertiary pediatric center.

Methods

A retrospective review was conducted of all boys with BUDT who had endocrine evaluation between 2008 and 2021 at the Royal Hospital for Children, Glasgow (RHCG). Continuous variables were analyzed using Mann-Whitney U and non-continuous variables using Fisher's exact, via Graphpad Prism v 8.0. Multivariable logistic regression was used to identify any associations between groups. A P < .05 was considered statistically significant.

Results

A total of 243 bilateral orchidopexies were performed at RHCG between 2008 and 2021. Of these 130 (53%) boys were seen by the endocrine team. The median (range) age at first orchidopexy was 1 year (0.2, 18.0) with 16 (12%) requiring re-do orchidopexy. The median External Masculinization Score of the group was 10 (2, 11) with 33 (25%) having additional genital features. Of the 130 boys, 71 (55%) had extragenital anomalies. Of the 70 who were tested, a genetic abnormality was detected in 38 (54%), most commonly a chromosomal variant in 16 (40%). Of the 100 who were tested, endocrine dysfunction was identified in 38 (38%).

Conclusion

Genetic findings and evidence of gonadal dysfunction are common in boys who are investigated secondary to presentation with BUDT. Endocrine and genetic evaluation should be part of routine clinical management of all cases of BUDT.

Update on the management of a newborn with a suspected difference of sex development

Differences or disorders of sex development are a group of heterogeneous conditions, which most commonly present in the newborn period, with the appearance of atypical genitalia on newborn examination. Over recent years, the improvement in our knowledge of these conditions has been accompanied by advances in diagnostic technology and therapeutic options, as well as societal shifts in attitudes and expectations. These factors have placed an even greater emphasis than before on the need for early expert input through a multidisciplinary service that can support the patient and the family; perform and interpret the investigations required to reach a diagnosis; and formulate a management plan that lays down the foundation for optimal long-term outcome. While providing a regional service, the expert team should also be committed to research and quality improvement through participation in national and international networks.

Genotype-Phenotype Correlation Analysis and Identification of a Novel SRD5A2 Mutation in Four Unrelated Chinese Patients with 5α-Reductase Deficiency

Objective

The 5α-reductase type 2 deficiency is mainly caused by mutations in the SRD5A2 gene. Our study aims to investigate the SRD5A2 gene mutations and their corresponding manifestations.

Methods

Four unrelated Chinese patients with 46, XY ambiguous genitalia were studied. Molecular genetic alterations and clinical presentations were analyzed.

Results

Five variants in the SRD5A2 gene were identified, all highly conserved in vertebrate orthologs. The p.P251A was a novel variant, predicted to “Affect protein function” and to be “probably damaging”. Combining patients’ gene mutations with their external genitalia and male sexual characteristics, we found that three variants, p.Q6X, p.N193S, and p.H90Y, were associated with severe undervirilization of external genitalia, and the other two, p.G203S and p.P251A, probably retained part of the enzyme activity.

Conclusion

Mutation analysis of SRD5A2 gene is crucial for differential diagnosis in patients with 5α-reductase type 2 deficiency. Patients’ variable manifestations depend on the mutation type and residual enzyme activity. The novel variant p.P251A enlarges the spectrum of SRD5A2 mutations.

The Use of Genetics for Reaching a Diagnosis in XY DSD

Reaching a firm diagnosis is vital for the long-term management of a patient with a difference or disorder of sex development (DSD). This is especially the case in XY DSD where the diagnostic yield is particularly low. Molecular genetic technology is playing an increasingly important role in the diagnostic process, and it is highly likely that it will be used more often at an earlier stage in the diagnostic process. In many cases of DSD, the clinical utility of molecular genetics is unequivocally clear, but in many other cases there is a need for careful exploration of the benefit of genetic diagnosis through long-term monitoring of these cases. Furthermore, the incorporation of molecular genetics into the diagnostic process requires a careful appreciation of the strengths and weaknesses of the evolving technology, and the interpretation of the results requires a clear understanding of the wide range of conditions that are associated with DSD.

Vascular dysfunction and increased cardiovascular risk in hypospadias

AIMS

Hypogonadism is associated with cardiovascular disease. However, the cardiovascular impact of hypogonadism during development is unknown. Using hypospadias as a surrogate of hypogonadism, we investigated whether hypospadias is associated with vascular dysfunction and is a risk factor for cardiovascular disease.

METHODS AND RESULTS

Our human study spanned molecular mechanistic to epidemiological investigations. Clinical vascular phenotyping was performed in adolescents with hypospadias and controls. Small subcutaneous arteries from penile skin from boys undergoing hypospadias repair and controls were isolated and functional studies were assessed by myography. Vascular smooth muscle cells were used to assess: Rho kinase, reactive oxygen species (ROS), nitric oxide synthase/nitric oxide, and DNA damage. Systemic oxidative stress was assessed in plasma and urine. Hospital episode data compared men with a history of hypospadias vs. controls. In adolescents with hypospadias, systolic blood pressure (P = 0.005), pulse pressure (P = 0.03), and carotid intima-media thickness standard deviation scores (P = 0.01) were increased. Arteries from boys with hypospadias demonstrated increased U46619-induced vasoconstriction (P = 0.009) and reduced acetylcholine-induced endothelium-dependent (P < 0.0001) and sodium nitroprusside-induced endothelium-independent vasorelaxation (P < 0.0001). Men born with hypospadias were at increased risk of arrhythmia [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.4-5.6, P = 0.003]; hypertension (OR 4.2, 95% CI 1.5-11.9, P = 0.04); and heart failure (OR 1.9, 95% CI 1.7-114.3, P = 0.02).

CONCLUSION

Hypospadias is associated with vascular dysfunction and predisposes to hypertension and cardiovascular disease in adulthood. Underlying mechanisms involve perturbed Rho kinase- and Nox5/ROS-dependent signalling. Our novel findings delineate molecular mechanisms of vascular injury in hypogonadism, and identify hypospadias as a cardiovascular risk factor in males.

DSDatlas: disorders of sex development atlas for reproductive endocrinology-related gene discovery in integrative omics platforms

OBJECTIVE

To facilitate the identification of related genes and candidate biomarkers for disorders of sex development (DSD), we present disorders of sex development atlas (http://dsd.geneworks.cn). Disorders of sex development are a spectrum of endocrine diseases with distinct mutations of genes or chromosomes, but several issues regarding their pathogenesis remain elusive. High-throughput methods have allowed genomic and transcriptomic analyses of DSD; however, these data are deposited in various repositories owing to a lack of integrated online resources.

DESIGN

A descriptive study of a specialized gene discovery platform designed for DSD.

SETTING

Publicly available DSD omics datasets and self-produced datasets.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The gene ranking result, with detailed information based on DSD terms in a gene-disease association knowledge base, and results of differential gene expression and mutation analyses from omics datasets.

RESULT(S)

The disorders of sex development atlas maintains both a knowledgebase for ranking DSD candidate genes and a database for DSD-related omics data analysis and visualization. We included 4 dominant classes of DSD in the knowledgebase: 15 subclasses and 44 specific disease names. Construction of the knowledgebase was centered upon Phenolyzer, with add-on seed gene databases customized by DSD-related genes collected from MalaCards, GeneCards, and DisGeNET. For the database, 25 experimental datasets related to DSD were integrated, including 24 public datasets from Gene Expression Omnibus and Sequence Read Archive and 1 self-generated dataset. A total of 474 samples from 240 DSD samples were collected for the database.

CONCLUSION(S)

This platform provides a friendly interface that integrates flexible and comprehensive analysis tools for differential expression and gene mutations between the DSD groups and controls.

Pubertal induction and transition to adult sex hormone replacement in patients with congenital pituitary or gonadal reproductive hormone deficiency: an Endo-ERN clinical practice guideline

An Endo-European Reference Network guideline initiative was launched including 16 clinicians experienced in endocrinology, pediatric and adult and 2 patient representatives. The guideline was endorsed by the European Society for Pediatric Endocrinology, the European Society for Endocrinology and the European Academy of Andrology. The aim was to create practice guidelines for clinical assessment and puberty induction in individuals with congenital pituitary or gonadal hormone deficiency. A systematic literature search was conducted, and the evidence was graded according to the Grading of Recommendations, Assessment, Development and Evaluation system. If the evidence was insufficient or lacking, then the conclusions were based on expert opinion. The guideline includes recommendations for puberty induction with oestrogen or testosterone. Publications on the induction of puberty with follicle-stimulation hormone and human chorionic gonadotrophin in hypogonadotropic hypogonadism are reviewed. Specific issues in individuals with Klinefelter syndrome or androgen insensitivity syndrome are considered. The expert panel recommends that pubertal induction or sex hormone replacement to sustain puberty should be cared for by a multidisciplinary team. Children with a known condition should be followed from the age of 8 years for girls and 9 years for boys. Puberty induction should be individualised but considered at 11 years in girls and 12 years in boys. Psychological aspects of puberty and fertility issues are especially important to address in individuals with sex development disorders or congenital pituitary deficiencies. The transition of these young adults highlights the importance of a multidisciplinary approach, to discuss both medical issues and social and psychological issues that arise in the context of these chronic conditions.

Surgical management and molecular diagnosis of persistent Müllerian duct syndrome in Chinese patients

Persistent Müllerian duct syndrome (PMDS) is a rare clinically and genetically overlapping disorder caused by mutations in the anti-Müllerian hormone (AMH) gene or the anti-Müllerian hormone receptor type 2 (AMHR2) gene. Affected individuals present uterus and tubes in normally virilized males and are discovered unexpectedly during other surgeries. Since it is rare and complex, a definitive clinical diagnosis can be missed, and there are no guidelines regarding how to deal with the uterus. In the present study, exome sequencing and Sanger verification were performed for causal variants in 12 PMDS patients. Preoperative diagnoses were made by positive exome sequencing in 8 patients. Of them, 7 patients evoked on the basis of ultrasound indicating bilateral testes on the same side of the body. Twelve different AMH variants (2 frameshift/nonsense, 1 deletion, 8 missense, and 1 in-frame) in 9 patients and 6 different AMHR2 variants (5 missense and 1 splicing) in 3 patients were identified. Seven variants were classified as "pathogenic" or "likely pathogenic", and 4 of them were novel. All but two patients with AMH defects showed low serum AMH concentrations, but all patients with AMHR2 defects showed elevated AMH levels. During surgery, an abnormal vas deferens was observed in half of the patients. Eight patients underwent orchidopexy with uterine preservation. Of them, 2 patients presented complications including irreducible cryptorchidism, and 3 patients developed Müllerian remnant cysts. Three patients underwent subtotal hysterectomy. Of them, one patient had complication of injury to the vas deferens, and one had hemorrhage after operation. This is the first report of PMDS involving a large Chinese population. The present study not only expands the variation spectrum but also provides clinical experience about the management of the uterus.

Society for Endocrinology UK Guidance on the initial evaluation of a suspected difference or disorder of sex development (Revised 2021)

It is paramount that any child or adolescent with a suspected difference or disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD and is discussed with the regional DSD service. In most cases, the paediatric endocrinologist within this service acts as the first point of contact but involvement of the regional multidisciplinary service will also ensure prompt access to specialist psychology and nursing care. The underlying pathophysiology of DSD and the process of delineating this should be discussed with the parents and affected young person with all diagnostic tests undertaken in a timely fashion. Finally, for rare conditions such as these, it is imperative that clinical experience is shared through national and international clinical and research collaborations.

El laboratorio en el diagnóstico multidisciplinar del desarrollo sexual anómalo o diferente (DSD)

Objetivos

El desarrollo de las características sexuales femeninas o masculinas acontece durante la vida fetal, determinándose el sexo genético, el gonadal y el sexo genital interno y externo (femenino o masculino). Cualquier discordancia en las etapas de diferenciación ocasiona un desarrollo sexual anómalo o diferente (DSD) que se clasifica según la composición de los cromosomas sexuales del cariotipo.

Contenido

En este capítulo se abordan la fisiología de la determinación y el desarrollo de las características sexuales femeninas o masculinas durante la vida fetal, la clasificación general de los DSD y su estudio diagnóstico clínico, bioquímico y genético que debe ser multidisciplinar. Los estudios bioquímicos deben incluir, además de las determinaciones bioquímicas generales, análisis de hormonas esteroideas y peptídicas, en condiciones basales o en pruebas funcionales de estimulación. El estudio genético debe comenzar con la determinación del cariotipo al que seguirá un estudio molecular en los cariotipos 46,XX ó 46,XY, orientado a la caracterización de un gen candidato. Además, se expondrán de manera específica los marcadores bioquímicos y genéticos en los DSD 46,XX, que incluyen el desarrollo gonadal anómalo (disgenesias, ovotestes y testes), el exceso de andrógenos de origen fetal (el más frecuente), fetoplacentario o materno y las anomalías del desarrollo de los genitales internos.

Perspectivas

El diagnóstico de un DSD requiere la contribución de un equipo multidisciplinar coordinado por un clínico y que incluya los servicios de bioquímica y genética clínica y molecular, un servicio de radiología e imagen y un servicio de anatomía patológica.

The laboratory in the multidisciplinary diagnosis of differences or disorders of sex development (DSD): III) Biochemical and genetic markers in the 46,XYIV) Proposals for the differential diagnosis of DSD

Objectives

46,XY differences/disorders of sex development (DSD) involve an abnormal gonadal and/or genital (external and/or internal) development caused by lack or incomplete intrauterine virilization, with or without the presence of Müllerian ducts remnants.

Content

Useful biochemical markers for differential diagnosis of 46,XY DSD include hypothalamic-pituitary-gonadal hormones such as luteinizing and follicle-stimulating hormones (LH and FSH; in baseline or after LHRH stimulation conditions), the anti-Müllerian hormone (AMH), inhibin B, insulin-like 3 (INSL3), adrenal and gonadal steroid hormones (including cortisol, aldosterone, testosterone and their precursors, dihydrotestosterone and estradiol) and the pituitary ACTH hormone. Steroid hormones are measured at baseline or after stimulation with ACTH (adrenal hormones) and/or with HCG (gonadal hormones).

Summary

Different patterns of hormone profiles depend on the etiology and the severity of the underlying disorder and the age of the patient at diagnosis. Molecular diagnosis includes detection of gene dosage or copy number variations, analysis of candidate genes or high-throughput DNA sequencing of panels of candidate genes or the whole exome or genome.

Outlook

Differential diagnosis of 46,XX or 46,XY DSD requires a multidisciplinary approach, including patient history and clinical, morphological, imaging, biochemical and genetic data. We propose a diagnostic algorithm suitable for a newborn with DSD that focuses mainly on biochemical and genetic data.

The laboratory in the multidisciplinary diagnosis of differences or disorders of sex development (DSD): I) Physiology, classification, approach, and methodologyII) Biochemical and genetic markers in 46,XX DSD

Objectives

The development of female or male sex characteristics occurs during fetal life, when the genetic, gonadal, and internal and external genital sex is determined (female or male). Any discordance among sex determination and differentiation stages results in differences/disorders of sex development (DSD), which are classified based on the sex chromosomes found on the karyotype.

Content

This chapter addresses the physiological mechanisms that determine the development of female or male sex characteristics during fetal life, provides a general classification of DSD, and offers guidance for clinical, biochemical, and genetic diagnosis, which must be established by a multidisciplinary team. Biochemical studies should include general biochemistry, steroid and peptide hormone testing either at baseline or by stimulation testing. The genetic study should start with the determination of the karyotype, followed by a molecular study of the 46,XX or 46,XY karyotypes for the identification of candidate genes.

Summary

46,XX DSD include an abnormal gonadal development (dysgenesis, ovotestes, or testes), an androgen excess (the most frequent) of fetal, fetoplacental, or maternal origin and an abnormal development of the internal genitalia. Biochemical and genetic markers are specific for each group.

Outlook

Diagnosis of DSD requires the involvement of a multidisciplinary team coordinated by a clinician, including a service of biochemistry, clinical, and molecular genetic testing, radiology and imaging, and a service of pathological anatomy.

El laboratorio en el diagnóstico multidisciplinar del desarrollo sexual anómalo o diferente (DSD): III) Marcadores bioquímicos y genéticos en los 46,XY IV) Propuestas para el diagnóstico diferencial de los DSD

Objetivos

El desarrollo sexual anómalo o diferente (DSD) con cariotipo 46,XY incluye anomalías en el desarrollo gonadal y/o genital (externo y/o interno).

Contenido

Los marcadores bioquímicos útiles para el diagnóstico diferencial de los DSD con cariotipo 46,XY incluyen las hormonas del eje hipotálamo-hipófiso gonadal como son las gonadotropinas LH y FSH (en condiciones basales o tras la estimulación con LHRH), la hormona anti-Mülleriana, la inhibina B, el factor insulinoide tipo 3 y las hormonas esteroideas de origen suprarrenal (se incluirá la hormona hipofisaria ACTH) y testicular (cortisol, aldosterona y sus precursores, testosterona y sus precursores, dihidrotestosterona y estradiol). Las hormonas esteroideas se analizarán en condiciones basales o tras la estimulación con ACTH (hormonas adrenales) y/o con HCG (hormonas testiculares). Los patrones de variación de las distintas hormonas dependerán de la causa y la edad de cada paciente. El diagnóstico molecular debe incluir el análisis de un gen candidato, un panel de genes o el análisis de un exoma completo.

Perspectivas

El diagnóstico diferencial de los DSD con cariotipos 46,XX ó 46,XY debe ser multidisciplinar, incluyendo los antecedentes clínicos, morfológicos, de imagen, bioquímicos y genéticos. Se han elaborado numerosos algoritmos diagnósticos.

Testosterone Therapy and Its Monitoring in Adolescent Boys with Hypogonadism: Results of an International Survey from the I-DSD Registry

It is unclear whether testosterone replacement therapy (TRT) in adolescent boys, affected by a range of endocrine diseases that may be associated with hypogonadism, is particularly common. The aim of this study was to assess the contemporary practice of TRT in boys included in the I-DSD Registry. All participating centres in the I-DSD Registry that had boys between 10 and 18 years of age and with a condition that could be associated with hypogonadism were invited to provide further information in 2019. Information on 162 boys was collected from 15 centres that had a median (range) number of 6 boys per centre (1.35). Of these, 30 (19%) from 9 centres were receiving TRT and the median (range) age at the start was 12.6 years (10.8-16.2), with 6 boys (20%) starting at <12 years. Median (range) age of boys not on TRT was 11.7 years (10.7-17.7), and 69 out of 132 (52%) were <12 years. TRT had been initiated in 20 of 71 (28%) boys with a disorder of gonadal development, 3 of 14 (21%) with a disorder of androgen synthesis, and all 7 (100%) boys with hypogonadotropic hypogonadism. The remainder who did not have TRT included 15 boys with partial androgen insensitivity, 52 with non-specific XY DSD, and 3 with persistent Müllerian duct syndrome. Before starting TRT, liver function and blood count were checked in 19 (68%) and 18 boys (64%), respectively, a bone age assessment was performed in 23 (82%) and bone mineral density assessment in 12 boys (43%). This snapshot of contemporary practice reveals that TRT in boys included in the I-DSD Registry is not very common, whilst the variation in starting and monitoring therapy is quite marked. Standardisation of practice may lead to more effective assessment of treatment outcomes.

Management of 46,XY Differences/Disorders of Sex Development (DSD) Throughout Life

Differences/disorders of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual's sex chromosomes, gonads, and/or anatomic sex. Advances in the clinical care of patients and families affected by 46,XY DSD have been achieved since publication of the original Consensus meeting in 2006. The aims of this paper are to review what is known about morbidity and mortality, diagnostic tools and timing, sex of rearing, endocrine and surgical treatment, fertility and sexual function, and quality of life in people with 46,XY DSD. The role for interdisciplinary health care teams, importance of establishing a molecular diagnosis, and need for research collaborations using patient registries to better understand long-term outcomes of specific medical and surgical interventions are acknowledged and accepted. Topics that require further study include prevalence and incidence, understanding morbidity and mortality as these relate to specific etiologies underlying 46,XY DSD, appropriate and optimal options for genitoplasty, long-term quality of life, sexual function, involvement with intimate partners, and optimizing fertility potential.

Clinical genetic testing in endocrinology: Current concepts and contemporary challenges

Recent advances in DNA sequencing technology have led to an unprecedented period of disease-gene discovery offering many new opportunities for genetic testing in the clinical setting. Endocrinology has seen a rapid expansion in the taxonomy of monogenic disorders, which can be detected by an expanding portfolio of genetic tests in both diagnostic and predictive settings. Successful testing relies on many factors including the ability to identify those at increased risk of genetic disease in the busy clinic as well as a working knowledge of the various testing platforms and their limitations. The clinical utility of a given test is dependent upon many factors, which include the reliability of the genetic testing platform, the accuracy of the test result interpretation and knowledge of disease penetrance and expression. The increasing adoption of "high-content" genetic testing based on next-generation sequencing (NGS) to diagnose hereditary endocrine disorders brings a number of challenges including the potential for uncertain test results and/or genetic findings unrelated to the indication for testing. Therefore, it is increasingly important that the clinician is aware of the current evolution in genetic testing, and understands the different settings in which it may be employed. This review provides an overview of the genetic testing workflow, focusing on each of the major components required for successful testing in adult and paediatric endocrine settings. In addition, the challenges of variant interpretation are highlighted, as are issues related to informed consent, prenatal diagnosis and predictive testing. Finally, the future directions of genetic testing relevant to endocrinology are discussed.

The Role of International Databases in Understanding the Aetiology and Consequences of Differences/Disorders of Sex Development

The International Disorders of Sex Development (I-DSD) and International Congenital Adrenal Hyperplasia registry (I-CAH) Registries were originally developed over 10 years ago and have since supported several strands of research and led to approximately 20 peer-reviewed publications. In addition to acting as an indispensable tool for monitoring clinical and patient-centered outcomes for improving clinical practice, the registries can support a wide nature of primary and secondary research and can also act as a platform for pharmacovigilance, given their ability to collect real world patient data within a secure, ethics approved virtual research environment. The challenge for the future is to ensure that the research community continues to use the registries to improve our understanding of Disorders of Sex Development (DSD).

Molecular genetics and phenotype/genotype correlation of 5-α reductase deficiency in a highly consanguineous population

CONTEXT AND OBJECTIVES

5-α reductase deficiency is a rare 46,XY disorder of sex development. We present detailed phenotypic and genotypic features of a cohort of 24 subjects from a highly consanguineous population of Saudi Arabia SUBJECTS AND METHODS: We studied the clinical presentation and hormonal profiles of 24 subjects diagnosed with 5-α reductase deficiency and performed genetic testing on DNA isolated from their peripheral blood using polymerase chain reaction and direct sequencing of the SRD5A2.

RESULTS

All subjects had 46,XY karyotype and presented with atypical appearance of external genitalia ranging from clitoromegaly, micophallus with hypospadias, undescended testes to completely normally looking female genitalia. Thirteen (54%) of them had severe under virilization and were assigned female sex at birth. The other 11 subjects were raised as males. Stimulated Testosterone:Dihydrotestosterone ratio was high in all 16 subjects in whom it was measured. The genetic testing revealed 2 nonsense mutations (p.R103X and p.R227X) in 2 unrelated subjects, 3 missense mutations (p.P181L, p.A228T, p.R246Q) in 11 subjects and a splice site mutation (IVS1-2A > G) in 11 other subjects. There was significant phenotypic variability even in subjects with the same mutation and also within the same family.

CONCLUSION

This is the first and largest report of the clinical and molecular genetics of 5-α reductase deficiency from the Middle East. It shows weak genotype/phenotype correlation and significant phenotypic heterogeneity. IVS1-2A > G mutation is the most common mutation and is likely to be a founder mutation in this part of the world.

Incidence and diagnoses of disorders of sex development in proximal hypospadias

BACKGROUND

Evidence-based guidelines on evaluation of boys with proximal hypospadias for the possibility of a disorder of sex development (DSD) have yet to be developed. We aimed to investigate the incidence and diagnoses of DSD in patients with proximal hypospadias.

METHODS

We retrospectively reviewed the records of consecutive boys who underwent proximal hypospadias repairs from 2006 to Sept 2017. Data collected included scrotal anomaly, testes position/palpability, micropenis, DSD investigations, and surgical techniques.

RESULTS

165 patients were eligible for the study. 14 (8.5%) were diagnosed to have DSD. The diagnoses were 46,XX testicular DSD [n = 1], 46,XY DSD [n = 7; partial gonadal dysgenesis (PGD) = 3; 5α-reductase type 2 deficiency = 3; 17α-hydroxylase deficiency = 1], Sex Chromosome DSD [n = 6; 45,X/46,XY PGD = 4; Klinefelter = 2]. 3/7 (43%) patients with PGD had gonadal germ cell neoplasms. Of the DSD patients, 6/14 (43%), 11/14 (79%) and 11/14 (79%) had undescended/impalpable testes, micropenis and penoscrotal transposition/bifid scrotum, respectively, significantly higher prevalence rates than those without DSD diagnosis (p-values <0.05). 10/14 (71.4%) DSD patients underwent 2-stage repair compared with 57/151 (37.7%) of others without DSD diagnosis (p = 0.01).

CONCLUSIONS

Patients presenting with proximal hypospadias and one or more of the coexisting anomalies of micropenis, undescended/impalpable testes, and penoscrotal transposition/bifid scrotum should warrant DSD evaluation. Presence of bilaterally descended testes in scrotum does not preclude the possibility of DSD.

LEVEL OF EVIDENCE

IV.

Integrating clinical and genetic approaches in the diagnosis of 46,XY disorders of sex development

46,XY differences and/or disorders of sex development (DSD) are clinically and genetically heterogeneous conditions. Although complete androgen insensitivity syndrome has a strong genotype-phenotype correlation, the other types of 46,XY DSD are less well defined, and thus, the precise diagnosis is challenging. This study focused on comparing the relationship between clinical assessment and genetic findings in a cohort of well-phenotyped patients with 46,XY DSD. The study was an analysis of clinical investigations followed by genetic testing performed on 35 patients presenting to a single center. The clinical assessment included external masculinization score (EMS), endocrine profiling and radiological evaluation. Array-comparative genomic hybridization (array-CGH) and sequencing of DSD-related genes were performed. Using an integrated approach, reaching the definitive diagnosis was possible in 12 children. The correlation between clinical and genetic findings was higher in patients with a more severe phenotype (median EMS 2.5 vs 6; P = 0.04). However, in 13 children, at least one variant of uncertain significance was identified, and most times this variant did not correspond to the original clinical diagnosis. In three patients, the genetic studies guided further clinical assessment which resulted in a reclassification of initial clinical diagnosis. Furthermore, we identified eight patients harboring variants in more than one DSD genes, which was not seen in controls (2.5%; P = 0.0003). In summary, taking into account potential challenges in reaching the definitive diagnosis in 46,XY DSD, only integrated approach seems to be the best routine practice.

GENETICS IN ENDOCRINOLOGY: Approaches to molecular genetic diagnosis in the management of differences/disorders of sex development (DSD): position paper of EU COST Action BM 1303 ‘DSDnet’

The differential diagnosis of differences or disorders of sex development (DSD) belongs to the most complex fields in medicine. It requires a multidisciplinary team conducting a synoptic and complementary approach consisting of thorough clinical, hormonal and genetic workups. This position paper of EU COST (European Cooperation in Science and Technology) Action BM1303 ‘DSDnet’ was written by leading experts in the field and focuses on current best practice in genetic diagnosis in DSD patients. Ascertainment of the karyotpye defines one of the three major diagnostic DSD subclasses and is therefore the mandatory initial step. Subsequently, further analyses comprise molecular studies of monogenic DSD causes or analysis of copy number variations (CNV) or both. Panels of candidate genes provide rapid and reliable results. Whole exome and genome sequencing (WES and WGS) represent valuable methodological developments that are currently in the transition from basic science to clinical routine service in the field of DSD. However, in addition to covering known DSD candidate genes, WES and WGS help to identify novel genetic causes for DSD. Diagnostic interpretation must be performed with utmost caution and needs careful scientific validation in each DSD case.

Genetic testing of XY newborns with a suspected disorder of sex development

PURPOSE OF REVIEW

The current review focuses on the neonatal presentation of disorders of sex development, summarize the current approach to the evaluation of newborns and describes recent advances in understanding of underlying genetic aetiology of these conditions.

RECENT FINDINGS

Several possible candidate genes as well as other adverse environmental factors have been described as contributing to several clinical subgroups of 46,XY DSDs. Moreover, registry-based studies showed that infants with suspected DSD may have extragenital anomalies and in 46,XY cases, being small for gestational age (SGA), cardiac and neurological malformations are the commonest concomitant conditions.

SUMMARY

Considering that children and adults with DSD may be at risk of several comorbidities a clear aetiological diagnosis will guide further management. To date, a firm diagnosis is not reached in over half of the cases of 46,XY DSD. Whilst it is likely that improved diagnostic resources will bridge this gap in the future, the next challenge to the clinical community will be to show that such advances will result in an improvement in clinical care.

The evaluation and management of the boy with DSD

Atypical genitalia in a boy may have a very wide and diverse aetiology and a definitive diagnosis is often challenging to reach. Detailed clinical evaluation integrated with extensive biochemical and genetic studies play an important role in this process. Such care should be undertaken in highly specialized centres that can also provide access to a multidisciplinary team for optimal long-term care.