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’

Ambiguous Genitalia Due to 3β-Hydroxysteroid Dehydrogenase Type 2 Deficiency: Clinical, Genetic, and Functional Characterization of Two Novel HSD3B2 Variants

3β-Hydroxysteroid dehydrogenase 2 deficiency (3βHSD2D) is a rare form of congenital adrenal hyperplasia (CAH) with variable clinical presentation. We describe a 46, XY child with ambiguous genitalia and CAH without apparent adrenal insufficiency due to 2 novel heterozygous variants in the HSD3B2 gene (c.779C > T/p.Pro260Leu and c.307 + 1G > A/p.Gly103Asp,fs29X). The disease-causing effect of the novel variants was assessed by genetic and functional studies informing on positive genotype-phenotype correlation. Sex registration was female, and no gender dysphoria has been noted until the present age of 7 years, but psychological assessments have been difficult with a concomitant diagnosis of autism spectrum disorder. Virilization that already progresses prepubertally through peripheral conversion of androgen precursors by 3β-hydroxysteroid dehydrogenase 1 will pose an increasing challenge during puberty.

Genomic testing for differences of sex development: Practices and perceptions of clinicians

OBJECTIVES

To investigate the approach taken by clinicians involved in the diagnosis and management of individuals with Differences of Sex Development (DSD), particularly with regard to genomic testing, and identify perceived gaps/strengths/barriers in current practice.

DESIGN AND METHODS

An anonymous online survey was developed, with questions exploring demographics, perceptions of genomic testing, availability of genetics services and opinions on the role and utility of genomic testing in DSD. All responses were anonymous. Clinicians involved in the diagnosis and management of individuals with DSD were recruited from relevant societies and departments across Australia and New Zealand.

RESULTS

79 eligible clinicians commenced the survey, with 63 completing it and 16 providing a partial response. The perceived benefit of having a genetic diagnosis for DSD was almost unanimous (97%). Almost half (48%) of respondents reported barriers in genomic testing. 81% of respondents reported they order genomic tests currently. Approaches to genomic testing when faced with four different clinical scenarios varied across respondents. Clinicians perceived genomic testing to be underutilised (median 36 on sliding scale from 0 to 100).

CONCLUSIONS

Despite 97% of respondents reporting benefit of a genetic diagnosis for individuals with DSD, this was not reflected throughout the survey with regard to clinical implementation. When faced with clinical scenarios, the recommendations for genomic testing from respondents was much lower, indicating the discrepancy between perception and clinical practice. Genomic testing in the context of DSD is seen as both beneficial and desired, yet there are multiple barriers impacting its integration into standard clinical care.

Severe Hyperandrogenism in 46,XX Congenital Adrenal Hyperplasia: Molecular Physiopathology, Late Diagnoses, and Personalized Management

Congenital Adrenal Hyperplasia (CAH) is a group of autosomal recessive endocrine disorders characterized by alteration in adrenal hormonal secretions. The most common form is caused by CYP21A2 mutations that result in 21-hydroxylase deficiency. Clinical features can vary, from salt-wasting forms, characterized by a lack of mineralocorticoid activity with a risk of perinatal-onset adrenal crises, to "simple-virilizing" forms with sufficient aldosterone secretion, up to milder "non-classical" forms, with a variable grade of hyperandrogenism but no severe hormonal deficiencies. During pregnancy, CAH 46,XX fetuses are exposed to elevated androgen levels, leading to a variable grade of virilization and potential central nervous system effects if untreated. These patients are usually (but not always) assigned female at birth, but some cases may be misdiagnosed and assigned male, potentially inducing fertility, gender identity, and sexual behavior issues in adulthood. In these patients, the benefits and risks of a late gender transition should be carefully evaluated. In this paper, we reviewed the literature concerning the most interesting peculiarities of these conditions.

Sex Assignment in Cases of Ambiguous Genitalia

Ambiguous genitalia is a rare disorder where it is unclear whether an infant's external genitals are male or female. This can be attributed to various internal and external etiologies, such as androgen receptor abnormalities, gonadal abnormalities (such as gonadal dysgenesis or Klinefelter syndrome where a male has an extra X chromosome), enzymatic defects, etc. Correction of such atypical genitalia requires a multidisciplinary approach, including but not limited to surgeons and therapists. It is important to keep in mind that the treatment plan is tailored according to the specific etiology that is causative of the patient's condition, along with the anticipated perioperative and postoperative complications. Islamically speaking, this topic has been addressed in various Islamic literature and disciplines, including guidelines for dealing with this medical condition. Moreover, follow-up of the patient must be done to allow smooth integration into society.

NR5A1/SF-1 Collaborates with Inhibin α and the Androgen Receptor

Steroidogenic factor 1 (SF-1) is a nuclear receptor that regulates steroidogenesis and reproductive development. NR5A1/SF-1 variants are associated with a broad spectrum of phenotypes across individuals with disorders of sex development (DSDs). Oligogenic inheritance has been suggested as an explanation. SF-1 interacts with numerous partners. Here, we investigated a constellation of gene variants identified in a 46,XY severely undervirilized individual carrying an ACMG-categorized 'pathogenic' NR5A1/SF-1 variant in comparison to the healthy carrier father. Candidate genes were revealed by whole exome sequencing, and pathogenicity was predicted by different in silico tools. We found variants in NR1H2 and INHA associated with steroidogenesis, sex development, and reproduction. The identified variants were tested in cell models. Novel SF-1 and NR1H2 binding sites in the AR and INHA gene promoters were found. Transactivation studies showed that wild-type NR5A1/SF-1 regulates INHA and AR gene expression, while the NR5A1/SF-1 variant had decreased transcriptional activity. NR1H2 was found to regulate AR gene transcription; however, the NR1H2 variant showed normal activity. This study expands the NR5A1/SF-1 network of interacting partners, while not solving the exact interplay of different variants that might be involved in revealing the observed DSD phenotype. It also illustrates that understanding complex genetics in DSDs is challenging.

A Novel NR5A1 Mutation in a Thai Boy with 46, XY DSD

Disorders of sex development (DSD) can be classified as 46,XX DSD, 46,XY DSD, and sex chromosome DSD. Several underlying causes including associated genes have been reported. Steroidogenic factor-1 is encoded by the NR5A1 gene, a crucial regulator of steroidogenesis in the growth of the adrenal and gonadal tissues. It has been discovered to be responsible for 10 to 20% of 46, XY DSD cases. Here, we described a 2-month-old infant who had ambiguous genitalia and 46, XY. Using whole exome sequencing followed by polymerase chain reaction-Sanger sequencing, a novel heterozygous nonsense c.1249C > T (p.Gln417Ter) variant in the NR5A1 gene was identified. It is present in his mother but absent in his father and maternal aunt and uncle. At the age of 7 months, the patient received a monthly intramuscular injection of low-dose testosterone for 3 months in a row. His penile length and diameter increased from 1.8 to 3 cm and from 0.8 to 1.3 cm, respectively. The patient also had normal adrenal reserve function by adrenocorticotropic hormone stimulation test. This study identified a novel causative p.Q417X (c.1249C > T) variant in NR5A1 causing 46,XY DSD in a Thai boy which is inherited from his unaffected mother.

Cytogenomic description of a Mexican cohort with differences in sex development

BACKGROUND

Differences in Sex Development (DSD) is a heterogeneous group of congenital alterations that affect inner and/or outer primary sex characters. Although these conditions do not represent a mortality risk, they can have a severe psycho-emotional impact if not appropriately managed. The genetic changes that can give rise to DSD are diverse, from chromosomal alterations to single base variants involved in the sexual development network. Epidemiological studies about DSD indicate a global frequency of 1:4500-5500, which can increase to 1:200-300, including isolated anatomical defects. To our knowledge, this study is the first to describe epidemiological and genetic features of DSD in a cohort of Mexican patients of a third-level care hospital.

METHODS

Descriptive and retrospective cross-sectional study that analyzed DSD patients from 2015 to 2021 attended a Paediatric Hospital from Mexico City.

RESULTS

One hundred one patients diagnosed with DSD were registered and grouped into different entities according to the Chicago consensus statement and the diagnosis defined by the multidisciplinary group. Of the total, 54% of them belong to the chromosomal DSD classification, 16% belongs to 46, XX and 30% of them belongs to the 46, XY classification.

CONCLUSION

The frequency for chromosomal DSDs was consistent with the literature; however, we found that DSD 46, XY is more frequent in our cohort, which may be due to the age of the patients captured, the characteristics of our study population, or other causes that depend on the sample size.

Variability in Sex Assignment at Birth and Etiological Diagnosis of Differences of Sex Development: A Ten-Year Institutional Experience from Assam

Introduction

Differences of sex development (DSD) also known as disorders of sex development encompass a wide spectrum of conditions with varying clinical presentations across different age groups. This study aims to analyse various aetiologies of DSD in Assam and the variability of sex assignment at birth.

Methods

This retrospective study included the records of people with DSD presenting to a tertiary centre over 10 years. The age at presentation, sex assignment, gender identity, degree of ambiguity, pertinent hormonal and radiological investigations were noted. Descriptive statistics were used for analysis.

Results

The age of presentation varied widely, with peaks during infancy and puberty. The most prevalent DSD type was 46, XY DSD (61.2%), followed by 46, XX DSD (19.7%) and sex chromosome DSD (19.1%). Among people with 46, XY DSD, androgen biosynthesis disorders were dominant, particularly 5-a reductase 2 deficiency (46.7%). Among 46, XX DSDs, the most common subtype was androgen excess disorders (51.7%) comprising 21a-hydroxylase deficiency (48,3%) and 11β-hydroxylase deficiency (3.4%). Turner syndrome was most prevalent among sex chromosome DSD (71.4%) with others being Klinefelter syndrome, 45, XO/46, XY mixed gonadal dysgenesis and 46, XX/46, XY chimerism. The degree of ambiguity was variable depending on the type of DSD and similarly, sex assignment at birth was influenced by the level of ambiguity.

Conclusion

The study underscores the significance of comprehensive approaches for DSD diagnosis and management, especially in regions with limited resources. The insights gained from this clinical study offer valuable understanding and aid in addressing the complexities associated with these conditions.

Digenic Origin of Difference of Sex Development in a Patient Harbouring DHX37 and MAMLD1 Variants

Background

The diagnostic process for identifying variations in sex development (DSD) remains challenging due to the limited availability of evidence pertaining to the association between phenotype and genotype. DSD incidence is reported as 2 in 10,000 births, and the etiology has been attributed to genetic causes. Case Presentation. The present study investigated genetic causes implicated in a case of a 15-year-old 46, XY patient, raised as a girl. Genetic analysis by clinical exome sequencing (CES) showed a digenic inheritance due to two known pathogenic mutations in the DHX37 gene and the MAMLD1 gene, while we excluded variants with pathogenic significance in 209 DSD-related genes.

Conclusions

Based on our literature review, this is the first case with the combined presence of pathogenic mutations in the MAMLD1 gene and DHX37 gene in a patient with gonadal dysgenesis.

SEC31A may be associated with pituitary hormone deficiency and gonadal dysgenesis

PURPOSE

Disorders/differences of sex development (DSD) result from variants in many different human genes but, frequently, have no detectable molecular cause.

METHODS

Detailed clinical and genetic phenotyping was conducted on a family with three children. A Sec31a animal model and functional studies were used to investigate the significance of the findings.

RESULTS

By trio whole-exome DNA sequencing we detected a heterozygous de novo nonsense SEC31A variant, in three children of healthy non-consanguineous parents. The children had different combinations of disorders that included complete gonadal dysgenesis and multiple pituitary hormone deficiency. SEC31A encodes a component of the COPII coat protein complex, necessary for intracellular anterograde vesicle-mediated transport between the endoplasmic reticulum (ER) and Golgi. CRISPR-Cas9 targeted knockout of the orthologous Sec31a gene region resulted in early embryonic lethality in homozygous mice. mRNA expression of ER-stress genes ATF4 and CHOP was increased in the children, suggesting defective protein transport. The pLI score of the gene, from gnomAD data, is 0.02.

CONCLUSIONS

SEC31A might underlie a previously unrecognised clinical syndrome comprising gonadal dysgenesis, multiple pituitary hormone deficiencies, dysmorphic features and developmental delay. However, a variant that remains undetected, in a different gene, may alternatively be causal in this family.

Clinical and genetic characteristics of a large international cohort of individuals with rare NR5A1/SF-1 variants of sex development

BACKGROUND

Steroidogenic factor 1 (SF-1/NR5A1) is essential for human sex development. Heterozygous NR5A1/SF-1 variants manifest with a broad range of phenotypes of differences of sex development (DSD), which remain unexplained.

METHODS

We conducted a retrospective analysis on the so far largest international cohort of individuals with NR5A1/SF-1 variants, identified through the I-DSD registry and a research network.

FINDINGS

Among 197 individuals with NR5A1/SF-1 variants, we confirmed diverse phenotypes. Over 70% of 46, XY individuals had a severe DSD phenotype, while 90% of 46, XX individuals had female-typical sex development. Close to 100 different novel and known NR5A1/SF-1 variants were identified, without specific hot spots. Additionally, likely disease-associated variants in other genes were reported in 32 individuals out of 128 tested (25%), particularly in those with severe or opposite sex DSD phenotypes. Interestingly, 48% of these variants were found in known DSD or SF-1 interacting genes, but no frequent gene-clusters were identified. Sex registration at birth varied, with <10% undergoing reassignment. Gonadectomy was performed in 30% and genital surgery in 58%. Associated organ anomalies were observed in 27% of individuals with a DSD, mainly concerning the spleen. Intrafamilial phenotypes also varied considerably.

INTERPRETATION

The observed phenotypic variability in individuals and families with NR5A1/SF-1 variants is large and remains unpredictable. It may often not be solely explained by the monogenic pathogenicity of the NR5A1/SF-1 variants but is likely influenced by additional genetic variants and as-yet-unknown factors.

FUNDING

Swiss National Science Foundation (320030-197725) and Boveri Foundation Zürich, Switzerland.

Variations in gender identity and sexual orientation of university students

Background

Previous studies have shown that a small percentage of people in the general population have atypical gender identity and/or sexual orientation.

Aim

This study aimed to explore variations in gender identity and sexual orientation in university students and determine genetic factors associated with these variations.

Methods

Deviations from complete gender congruence and exclusive heterosexual orientation in 736 Japanese university students were quantitatively assessed with self-assessment questionnaires. Next, we conducted genetic tests for 80 participants who showed relatively low gender identity scores and/or atypical sexual orientation. These genetic tests consisted of repeat number analysis of the androgen receptor gene (AR) and a SKAT-O: an optimal unified sequence kernel association test, which is an exome-based rare variant association study. The results of the genetic tests were compared with the Japanese reference data and the results of our 637 control samples.

Outcomes

We calculated the gender identity and sexual orientation scores of all participants and analyzed the molecular data of 80 selected participants.

Results

The gender identity scores of 736 participants were broadly distributed: only ~15% of natal males and ~5% of natal females had the maximum score that corresponds to complete gender congruence. The sexual orientation scores also varied: ~80% of natal males and ~60% of natal females showed exclusive heterosexual orientation. We found no association between gender characteristics and AR repeat numbers. The SKAT-O showed that rare damaging variants of TDRP and 3 other genes were more common in the 80 participants than in the control group.

Clinical Implications

Our data support the view that gender is a phenotypic continuum rather than a binary trait.

Strength and Limitations

This study quantitatively assessed the gender characteristics of a large cohort of university students. Moreover, we conducted systematic screening for genetic factors associated with gender variations. The weaknesses of the study were the limited analytic power of the questionnaires, the relatively small sample for molecular analyses, and incomplete clinical information and relatively advanced ages of the control group.

Conclusion

This study revealed significant variations in gender identity and sexual orientation in university students, which may be partly associated with variants in TDRP or other genes.

Contexts of care for people with differences of sex development: Diversity is still missing in the laboratory routine

The 2006 Chicago consensus statement of management of disorders/difference of sex development (DSD) has achieved advantages in clinical care and diagnosis for patients and families affect by DSD. This article provides a brief overview of contexts of care for physicians, and points out specific challenges in clinical practice that have arisen from the transformations of the sex/gender system in recent years. We focus on the impact of diagnosis and laboratory measurements. Both laboratory measurements and hormonal therapies still depend on the binary system. One problem is the lack of reference intervals for the different forms of DSD, which means that diversity is often neglected. In the following, we will give a brief insight into this complex topic.

Sex difference and risk factors in burden of urogenital congenital anomalies from 1990 to 2019

Urogenital congenital anomalies (UCAs) is defined as "any live-birth with a urinary or genital condition" and affects millions of men and women worldwide. However, sex differences and related environmental risk factors in UCAs burden on a global scale have not been assessed. Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated prevalence, incidence, mortality and disability-adjusted life years (DALYs) of UCAs from 1990 to 2019 by sex, region, and socio-demographic Index (SDI) in 204 countries and territories. The disease burden of UCAs was also estimated attributable to each risk factor were estimated according to risk exposure. In 2019, UCAs caused 10,200 all-ages deaths (95% UI 7550-13,400). The combined global incidence rate was 8.38 per 1000 (95% UI 5.88-12.0) live births. The ASIR increased slightly, while the ASDR decreased from 1990 to 2019.The UCAs burden varies greatly depending on the development level and geographical location. The UCAs burden was significantly higher in men than in women, and the sex differences showed an enlarging trend. Health risks and issues, including pollution, child and maternal malnutrition, diet habits, unsafe sanitation and water source, were detected to be positively related to UCAs burden. Albeit the age-standardised prevalence, mortality, incidence, and DALYs of UCAs have decreased, they still cause a public health challenge worldwide. The high deaths and DALYs rates in low and low-middle SDI countries highlight the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for enhancing water safety, reducing pollution, and healthy diets are crucial steps in reducing the burden of UCAs.

Imprinting disorders

Imprinting disorders (ImpDis) are congenital conditions that are characterized by disturbances of genomic imprinting. The most common individual ImpDis are Prader-Willi syndrome, Angelman syndrome and Beckwith-Wiedemann syndrome. Individual ImpDis have similar clinical features, such as growth disturbances and developmental delay, but the disorders are heterogeneous and the key clinical manifestations are often non-specific, rendering diagnosis difficult. Four types of genomic and imprinting defect (ImpDef) affecting differentially methylated regions (DMRs) can cause ImpDis. These defects affect the monoallelic and parent-of-origin-specific expression of imprinted genes. The regulation within DMRs as well as their functional consequences are mainly unknown, but functional cross-talk between imprinted genes and functional pathways has been identified, giving insight into the pathophysiology of ImpDefs. Treatment of ImpDis is symptomatic. Targeted therapies are lacking owing to the rarity of these disorders; however, personalized treatments are in development. Understanding the underlying mechanisms of ImpDis, and improving diagnosis and treatment of these disorders, requires a multidisciplinary approach with input from patient representatives.

Variants in SART3 cause a spliceosomopathy characterised by failure of testis development and neuronal defects

Squamous cell carcinoma antigen recognized by T cells 3 (SART3) is an RNA-binding protein with numerous biological functions including recycling small nuclear RNAs to the spliceosome. Here, we identify recessive variants in SART3 in nine individuals presenting with intellectual disability, global developmental delay and a subset of brain anomalies, together with gonadal dysgenesis in 46,XY individuals. Knockdown of the Drosophila orthologue of SART3 reveals a conserved role in testicular and neuronal development. Human induced pluripotent stem cells carrying patient variants in SART3 show disruption to multiple signalling pathways, upregulation of spliceosome components and demonstrate aberrant gonadal and neuronal differentiation in vitro. Collectively, these findings suggest that bi-allelic SART3 variants underlie a spliceosomopathy which we tentatively propose be termed INDYGON syndrome (Intellectual disability, Neurodevelopmental defects and Developmental delay with 46,XY GONadal dysgenesis). Our findings will enable additional diagnoses and improved outcomes for individuals born with this condition.

Individuals with numerical and structural variations of sex chromosomes: interdisciplinary management with focus on fertility potential

Diagnosis and management of individuals who have differences of sex development (DSD) due to numerical or structural variations of sex chromosomes (NSVSC) remains challenging. Girls who have Turner syndrome (45X) may present with varying phenotypic features, from classical/severe to minor, and some remain undiagnosed. Boys and girls who have 45,X/46,XY chromosomal mosaicism may have Turner syndrome-like features and short stature; therefore, unexplained short stature during childhood requires karyotype analysis in both sexes, particularly if characteristic features or atypical genitalia are present. Many individuals with Klinefelter syndrome (47XXY) remain undiagnosed or are only diagnosed as adults due to fertility problems. Newborn screening by heel prick tests could potentially identify sex chromosome variations but would have ethical and financial implications, and in-depth cost-benefit analyses are needed before nationwide screening can be introduced. Most individuals who have NSVSC have lifelong co-morbidities and healthcare should be holistic, personalized and centralized, with a focus on information, psychosocial support and shared decision-making. Fertility potential should be assessed individually and discussed at an appropriate age. Oocyte or ovarian tissue cryopreservation is possible in some women who have Turner syndrome and live births have been reported following assisted reproductive technology (ART). Testicular sperm cell extraction (TESE) is possible in some men who have 45,X/46,XY mosaicism, but there is no established protocol and no reported fathering of children. Some men with Klinefelter syndrome can now father a child following TESE and ART, with multiple reports of healthy live births. Children who have NSVSC, their parents and DSD team members need to address possibilities and ethical questions relating to potential fertility preservation, with guidelines and international studies still needed.

Genetic control of typical and atypical sex development

Sex development relies on the sex-specific action of gene networks to differentiate the bipotential gonads of the growing fetus into testis or ovaries, followed by the differentiation of internal and external genitalia depending on the presence or absence of hormones. Differences in sex development (DSD) arise from congenital alterations during any of these processes, and are classified depending on sex chromosomal constitution as sex chromosome DSD, 46,XY DSD or 46,XX DSD. Understanding the genetics and embryology of typical and atypical sex development is essential for diagnosing, treating and managing DSD. Advances have been made in understanding the genetic causes of DSD over the past 10 years, especially for 46,XY DSD. Additional information is required to better understand ovarian and female development and to identify further genetic causes of 46,XX DSD, besides congenital adrenal hyperplasia. Ongoing research is focused on the discovery of further genes related to typical and atypical sex development and, therefore, on improving diagnosis of DSD.

Characterisation of eight cattle with Swyer syndrome by whole-genome sequencing

Swyer syndrome is where an individual has the karyotype of a typical male yet is phenotypically a female. The lack of a (functional) SRY gene located on the Y-chromosome is implicated in some cases of the Swyer syndrome, although many Swyer individuals with an apparently fully functional SRY gene have also been documented. The present study undertook whole genome sequence analyses of eight cattle with suspected Swyer syndrome and compared their genome to that of both a control male and female. Sequence analyses coupled with female phenotypes confirmed that all eight individuals had the 60,XY sex reversal Swyer syndrome. Seven of the eight Swyer syndrome individuals had a deletion on the Y chromosome encompassing the SRY gene (i.e., SRY-). The eighth individual had no obvious mutation in the SRY gene (SRY+) or indeed in any reported gene associated with sex reversal in mammals; a necropsy was performed on this individual. No testicles were detected during the necropsy. Histological examination of the reproductive tract revealed an immature uterine body and horns with inactive glandular tissue of normal histological appearance; both gonads were elongated, a characteristic of most reported cases of Swyer in mammals. The flanking sequence of 11 single nucleotide polymorphisms within 10 kb of the SRY gene are provided to help diagnose some cases of Swyer syndrome. These single nucleotide polymorphisms will not, however, detect all cases of Swyer syndrome since, as evidenced from the present study (and other studies), some individuals with the Swyer condition still contain the SRY gene (i.e., SRY+).

Differences of sexual development: genetic counseling considerations in the prenatal setting

PURPOSE OF REVIEW

With the rapid adoption of noninvasive prenatal screening (NIPS), predictive fetal sex information is available early in pregnancy. This information can conflict with the results of other prenatal tests such as fetal ultrasound or diagnostic testing and raise the possibility of a fetal difference of sexual development (DSD). In this review, we describe recent studies examining the counseling and outcomes of prenatally suspected DSD.

RECENT FINDINGS

Discordance in prenatal genetic testing results can cause confusion and anxiety in families as expectations of testing are not often discussed in detail prior to testing. There are no established guidelines for the counseling or management of such situations.

SUMMARY

We present case vignettes to highlight relevant counseling points and considerations to aid in the development of guidelines and best practices in the management of DSD in the prenatal setting.

Role of chromosomal imbalances in the pathogenesis of DSD: A retrospective analysis of 115 prenatal samples

Differences of sex development (DSDs) are a group of congenital conditions characterized by a discrepancy between chromosomal, gonadal, and genital sex development of an individual, with significant impact on medical, psychological and reproductive life. The genetic heterogeneity of DSDs complicates the diagnosis and almost half of the patients remains undiagnosed. In this context, chromosomal imbalances in syndromic DSD patients may help to identify new genes implicated in DSDs. In this study, we aimed at describing the burden of chromosomal imbalances including submicroscopic ones (copy number variants or CNVs) in a cohort of prenatal syndromic DSD patients, and review their role in DSDs. Our patients carried at least one pathogenic or likely pathogenic chromosomal imbalance/CNV or low-level mosaicism for aneuploidy. Almost half of the cases resulted from an unbalanced chromosomal rearrangement. Chromosome 9p/q, 4p/q, 3q and 11q anomalies were more frequently observed. Review of the literature confirmed the causative role of CNVs in DSDs, either in disruption of known DSD-causing genes (SOX9, NR0B1, NR5A1, AR, ATRX, …) or as a tool to suspect new genes in DSDs (HOXD cluster, ADCY2, EMX2, CAMK1D, …). Recurrent CNVs of regulatory elements without coding sequence content (i.e. duplications/deletions upstream of SOX3 or SOX9) confirm detection of CNVs as a mean to explore our non-coding genome. Thus, CNV detection remains a powerful tool to explore undiagnosed DSDs, either through routine techniques or through emerging technologies such as long-read whole genome sequencing or optical genome mapping.

Bioinformatics analysis and verification of hub genes in 46,XY, disorders of sexual development

CONTEXT

46,XY, disorders of sexual development (46,XY, DSD) is a congenital genetic disease whose pathogenesis is complex and clinical manifestations are diverse. The existing molecular research has often focused on single-centre sequencing data, instead of prediction based on big data.

AIMS

This work aimed to fully understand the pathogenesis of 46,XY, DSD, and summarise the key pathogenic genes.

METHODS

Firstly, the potential pathogenic genes were identified from public data. Secondly, bioinformatics was used to predict pathogenic genes, including hub gene analysis, protein-protein interaction (PPI) and function enrichment analysis. Lastly, the genomic DNA from two unrelated families were recruited, next-generation sequencing and Sanger sequencing were performed to verify the hub genes.

KEY RESULTS

A total of 161 potential pathogenic genes were selected from MGI and PubMed gene sets. The PPI network was built which included 144 nodes and 194 edges. MCODE 4 was selected from PPI which scored the most significant P -value. The top 15 hub genes were ranked and identified by Cytoscape. Furthermore, three variants were found on SRD5A2 gene by genome sequencing, which belonged to the prediction hub genes.

CONCLUSIONS

Our results indicate that occurrence of 46,XY, DSD is attributed to a variety of genes. Bioinformatics analysis can help us predict the hub genes and find the most core network MCODE model.

IMPLICATIONS

Bioinformatic predictions may provide a novel perspective on better understanding the pathogenesis of 46,XY, DSD.

Anomalies in Human Sex Determination: Usefulness of a Combined Cytogenetic Approach to Characterize an Additional Case with Xp Functional Disomy Associated with 46,XY Gonadal Dysgenesis

OBJECTIVE

Disorders of sexual development (DSD) are a heterogeneous group of genital defects affecting chromosomal, gonadal and anatomical sex. 46,XY DSD is a subset of DSD which covers a wide range of phenotypes in which 46,XY gonadal dysgenesis (GD) is the most severe form. In this study, we report on the clinical and molecular cytogenetic findings of a study on a Tunisian girl with the syndromic form of 46,XY DSD.

METHODS

This case was a phenotypic female patient having several congenital anomalies including growth retardation. Karyotype, fluorescence in situ hybridization and array Comparative Genome Hybridization (array CGH) were performed.

RESULTS

The proband exhibited a de-novo 46,X,der(Y) karyotype. Array CGH revealed a pathogenic 27.5Mb gain of an Xp21.2 chromosome segment leading to Xp functional disomy. No deletion was observed in the Y-chromosome. The duplicated region encompassed the NR0B1 (DAX1) and MAGEB genes, located within the dosage sensitive sex (DSS) reversal locus, known as promote genes responsible for human sex reversal and testis repression. The extra-dosage and interactions of these genes with different specific genes could result in the impairment of the male sex pathway. Over-dosage of KAL1 and IL1RAPL1 genes fall within the somatic features observed in the patient.

CONCLUSION

To the best of our knowledge, we report on the fourth case of Xp21.2-pter duplication within Xp;Yp translocation associated with XY GD. Our findings suggest that when duplicated, the NR0B1 and MAGEB genes could be a major cause of XY GD. Therefore, we emphasize the usefulness of a combined cytogenetic approach in order to provide an accurate genetic diagnosis for those patients having syndromic XY DSD in a clinical setting.

Diagnostic approach in 46, XY DSD: an endocrine society of bengal (ESB) consensus statement

OBJECTIVES

46, XY difference/disorder of sex development (DSD) is a relatively uncommon group of heterogeneous disorders with varying degree of underandrogenization of male genitalia. Such patients should be approached systematically to reach an aetiological diagnosis. However, we lack, at present, a clinical practice guideline on diagnostic approach in 46, XY DSD from this part of the globe. Moreover, debate persists regarding the timing and cut-offs of different hormonal tests, performed in these cases. The consensus committee consisting of 34 highly experienced endocrinologists with interest and experience in managing DSD discussed and drafted a consensus statement on the diagnostic approach to 46, XY DSD focussing on relevant history, clinical examination, biochemical evaluation, imaging and genetic analysis.

CONTENT

The consensus was guided by systematic reviews of existing literature followed by discussion. An initial draft was prepared and distributed among the members. The members provided their scientific inputs, and all the relevant suggestions were incorporated. The final draft was approved by the committee members.

SUMMARY

The diagnostic approach in 46, XY DSD should be multidisciplinary although coordinated by an experienced endocrinologist. We recommend formal Karyotyping, even if Y chromosome material has been detected by other methods. Meticulous history taking and thorough head-to-toe examination should initially be performed with focus on external genitalia, including location of gonads. Decision regarding hormonal and other biochemical investigations should be made according to the age and interpreted according to age-appropriate norms Although LC-MS/MS is the preferred mode of steroid hormone measurements, immunoassays, which are widely available and less expensive, are acceptable alternatives. All patients with 46, XY DSD should undergo abdominopelvic ultrasonography by a trained radiologist. MRI of the abdomen and/or laparoscopy may be used to demonstrate the Mullerian structure and/or to localize the gonads. Genetic studies, which include copy number variation (CNV) or molecular testing of a candidate gene or next generation sequencing then should be ordered in a stepwise manner depending on the clinical, biochemical, hormonal, and radiological findings.

OUTLOOK

The members of the committee believe that patients with 46, XY DSD need to be approached systematically. The proposed diagnostic algorithm, provided in the consensus statement, is cost effective and when supplemented with appropriate genetic studies, may help to reach an aetiological diagnosis in majority of such cases.

Co-Occurrence of a Pathogenic HSD3B2 Variant and a Duplication on 10q22.3-q23.2 Detected in Newborn Twins with Salt-Wasting Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders caused by enzyme deficiencies required for cortisol biosynthesis in the adrenal cortex. The majority of CAH are due to the deficiency of the 21-hydroxylase enzyme, while 3β-hydroxysteroid dehydrogenase type 2 deficiency accounts for less than five percent of all CAH cases. We report two Moroccan twins from a spontaneous triplet pregnancy. The 46,XY newborn exhibited a disorder of sexual differentiation (DSD) with hypo virilization, while the 46,XX newborn had normal female external genitalia. In the first week of life, they showed hyponatremia and primary adrenal insufficiency with a slight 17OHP elevation and increased DHEAS and renin levels. The aCGH-SNP analysis disclosed a 8.36 Mb long contiguous stretch of homozygosity (LCSH) on chromosome 1p13.2-p11.2 including the candidate HSD3B2 gene, a LCSH of 7.3 Mb on 14q31.1-q32.11, and a 7 Mb duplication on 10q22.3-q23.2. Clinical exome sequencing revealed the biallelic c.969T > G (p.Asn323Lys) HSD3B2, likely pathogenic, variant in both of the affected twins. This case emphasizes the importance of a prompt molecular diagnosis performed through the combination of aCGH and clinical exome, both for establishment of correct therapy and for follow-up, as the newborns also carry a genomic rearrangement with possible clinical implications.

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.

Disruption of the topologically associated domain at Xp21.2 is related to 46,XY gonadal dysgenesis

Background

Duplications at the Xp21.2 locus have previously been linked to 46,XY gonadal dysgenesis (GD), which is thought to result from gene dosage effects of NR0B1 (DAX1), but the exact disease mechanism remains unknown.

Methods

Patients with 46,XY GD were analysed by whole genome sequencing. Identified structural variants were confirmed by array CGH and analysed by high-throughput chromosome conformation capture (Hi-C).

Results

We identified two unrelated patients: one showing a complex rearrangement upstream of NR0B1 and a second harbouring a 1.2 Mb triplication, including NR0B1. Whole genome sequencing and Hi-C analysis revealed the rewiring of a topological-associated domain (TAD) boundary close to NR0B1 associated with neo-TAD formation and may cause enhancer hijacking and ectopic NR0B1 expression. Modelling of previous Xp21.2 structural variations associated with isolated GD support our hypothesis and predict similar neo-TAD formation as well as TAD fusion.

Conclusion

Here we present a general mechanism how deletions, duplications or inversions at the NR0B1 locus can lead to partial or complete GD by disrupting the cognate TAD in the vicinity of NR0B1. This model not only allows better diagnosis of GD with copy number variations (CNVs) at Xp21.2, but also gives deeper insight on how spatiotemporal activation of developmental genes can be disrupted by reorganised TADs causing impairment of gonadal development.

Case Report: Severe Gonadal Dysgenesis Causing 46,XY Disorder of Sex Development Due to a Novel NR5A1 Variant

Mutations in the nuclear receptor subfamily 5 group A member 1 (NR5A1) are the underlying cause of 10–20% of 46,XY disorders of sex development (DSDs). We describe a young girl with 46,XY DSD due to a unique novel mutation of the NR5A1 gene. An 11-year-old subject, raised as a female, was noticed to have clitromegly. She looked otherwise normal. However, her evaluation revealed a 46,XY karyotype, moderate clitromegly but otherwise normal female external genitalia, undescended atrophied testes, rudimentary uterus, no ovaries, and lack of breast development. Serum testosterone and estradiol were low, and gonadotropins were elevated. Adrenocortical function was normal. DNA was isolated from the peripheral leucocytes and used for whole exome sequencing. The results were confirmed by Sanger sequencing. We identified a novel mutation in NR5A1 changing the second nucleotide of the translation initiation codon (ATG>ACG) and resulting in a change of the first amino acid, methionine to threonine (p.Met1The). This led to severe gonadal dysgenesis with deficiency of testosterone and anti-Müllerian hormone (AMH) secretion. Lack of the former led to the development of female external genitalia, and lack of the latter allowed the Müllerian duct to develop into the uterus and the upper vagina. The patient has a female gender identity. Bilateral orchidectomy was performed and showed severely atrophic testes. Estrogen/progesterone therapy was initiated with excellent breast development and normal cyclical menses. In summary, we describe a severely affected case of 46,XY DSD due to a novel NR5A1 mutation involving the initiation codon that fully explains the clinical phenotype in this subject.

Diagnosis of DSD in Children—Development of New Tools for a Structured Diagnostic and Information Management Program within the Empower-DSD Study

Background: Current recommendations define a structured diagnostic process, transparent information, and psychosocial support by a specialized, multi-professional team as central in the care for children and adolescents with genital variations and a suspected difference of sex development (DSD). The active involvement of the child and their parents in shared decision-making should result in an individualized care plan. So far, this process has not been standardized. Methods: Within the Empower-DSD study, a team of professionals and representatives of patient advocacy groups developed a new diagnostic and information management program based on current recommendations and existing patient information. Results: The information management defines and standardizes generic care elements for the first weeks after a suspected DSD diagnosis. Three different tools were developed: a guideline for the specialized multiprofessional team, a personal health record and information kit for the child with DSD and their family, and a booklet for medical staff not specialized in DSD. Conclusions: The new information management offers guidance for patients and professionals during the first weeks after a DSD diagnosis is suspected. The developed tools’ evaluation will provide further insight into the diagnostic and information-sharing process as well as into all of the involved stakeholders’ needs.

Construction of Copy Number Variation Map Identifies Small Regions of Overlap and Candidate Genes for Atypical Female Genitalia Development

Copy number variations (CNVs) have been implicated in various conditions of differences of sexual development (DSD). Generally, larger genomic aberrations are more often considered disease-causing or clinically relevant, but over time, smaller CNVs have been associated with various forms of DSD. The main objective of this study is to identify small CNVs and the smallest regions of overlap (SROs) in patients with atypical female genitalia (AFG) and build a CNV map of AFG. We queried the DECIPHER database for recurrent duplications and/or deletions detected across the genome of AFG individuals. From these data, we constructed a chromosome map consisting of SROs and investigated such regions for genes that may be associated with the development of atypical female genitalia. Our study identified 180 unique SROs (7.95 kb to 45.34 Mb) distributed among 22 chromosomes. The most SROs were found in chromosomes X, 17, 11, and 22. None were found in chromosome 3. From these SROs, we identified 22 genes as potential candidates. Although none of these genes are currently associated with AFG, a literature review indicated that almost half were potentially involved in the development and/or function of the reproductive system, and only one gene was associated with a disorder that reported an individual patient with ambiguous genitalia. Our data regarding novel SROs requires further functional investigation to determine the role of the identified candidate genes in the development of atypical female genitalia, and this paper should serve as a catalyst for downstream molecular studies that may eventually affect the genetic counseling, diagnosis, and management of these DSD patients.

Temporal sociomedical approaches to intersex* bodies

The history of the field of intersex bodies/bodies with variations of sex development (VSD) reflects the ongoing tension between sociomedical attempts to control uncertainty and reduce the duration of corporeal uncertainty by means of early diagnosis and treatment, and the embodied subjects who resist or challenge these attempts, which ultimately increase uncertainty. Based on various qualitative studies in the field of intersex, this article describes three temporal sociomedical approaches that have evolved over the last decade and aims to address the uncertainty surrounding intersex/VSD bodies. These approaches are (1) the corrective-concealing approach, which includes early surgeries and hormone therapies intended to "correct" intersex conditions and the deliberate concealment of the ambiguity and uncertainty associated with intersex conditions; (2) the preventive approach, which involves early genetic diagnostic methods aimed at regulating or preventing the recurrence of hereditary conditions under the umbrella of VSD; and (3) the wait-and-see approach, which perceives intersex bodies as natural variations and encourages parents to take time, wait, and give their children the right to bodily autonomy. A comparison of these approaches from biopolitical, phenomenological, and pragmatic perspectives reveals that time is an essential social agent in addressing and controlling uncertainty, a gatekeeper of social norms and social and physical orders, and, on the other hand, a sociopolitical agent that enables creative social change.

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.

Delivery of multidisciplinary care in the field of differences and disorders of sex development (DSD)

INTRODUCTION

Differences and disorders of sex development (DSD) are a diverse group of conditions, which often present in early childhood and may require input from a group of experts in a wide range of clinical fields. Clinical guidance in this field recommends that these experts function as a multidisciplinary team (MDT) within which each expert has a defined role, which ensures an integrated and streamlined approach to the care of affected individuals.

AREAS COVERED

This review will focus on the benefits of multidisciplinary care for people with DSD, as well as the challenges that may be faced.

EXPERT OPINION

Core members of the MDT for people with DSD include endocrinologists, surgeons, psychologists, geneticists, specialist nurses, radiologists, and gynecologists, although many other health-care professionals may also be pertinent, at different stages of the patient's life. With greater acceptance of remote and digital health-care technology, there is a need to review the traditional concepts of the clinical MDT so that new care models can be explored for effective and efficient delivery of complex care.

Disorders of Sex Development in a Large Ukrainian Cohort: Clinical Diversity and Genetic Findings

BACKGROUND

The clinical profile and genetics of individuals with Disorders/Differences of Sex Development (DSD) has not been reported in Ukraine.

MATERIALS AND METHODS

We established the Ukrainian DSD Register and identified 682 DSD patients. This cohort includes, 357 patients (52.3% [303 patients with Turner syndrome)] with sex chromosome DSD, 119 (17.5%) with 46,XY DSD and 206 (30.2%) with 46,XX DSD. Patients with sex chromosome DSD and congenital adrenal hyperplasia (CAH, n=185) were excluded from further studies. Fluorescence in situ hybridization (FISH) was performed for eight 46,XX boys. 79 patients underwent Whole Exome Sequencing (WES).

RESULTS

The majority of patients with 46,XY and 46,XX DSD (n=140), were raised as female (56.3% and 61.9% respectively). WES (n=79) identified pathogenic (P) or likely pathogenic (LP) variants in 43% of the cohort. P/LP variants were identified in the androgen receptor (AR) and NR5A1 genes (20.2%). Variants in other DSD genes including AMHR2, HSD17B3, MYRF, ANOS1, FGFR11, WT1, DHX37, SRD5A1, GATA4, TBCE, CACNA1A and GLI2 were identified in 22.8% of cases. 83.3% of all P/LP variants are novel. 35.3% of patients with a genetic diagnosis had an atypical clinical presentation. A known pathogenic variant in WDR11, which was reported to cause congenital hypogonadotropic hypogonadism (CHH), was identified in individuals with primary hypogonadism.

CONCLUSIONS

WES is a powerful tool to identify novel causal variants in patients with DSD, including a significant minority that have an atypical clinical presentation. Our data suggest that heterozygous variants in the WDR11 gene are unlikely to cause of CHH.

Rare forms of genetic steroidogenic defects affecting the gonads and adrenals

Pathogenic variants have been found in all genes involved in the classic pathways of human adrenal and gonadal steroidogenesis. Depending on their function and severity, they cause characteristic disorders of corticosteroid and/or sex hormone deficiency, may result in atypical sex development at birth and/or puberty, and mostly lead to sexual dysfunction and infertility. Genetic disorders of steroidogenesis are all inherited in an autosomal recessive fashion. Loss of function mutations lead to typical phenotypes, while variants with partial activity may manifest with milder, non-classic, late-onset disorders that share similar phenotypes. Thus, these disorders of steroidogenesis are diagnosed by comprehensive phenotyping, steroid profiling and genetic testing using next generation sequencing techniques. Treatment comprises of steroid replacement therapies, but these are insufficient in many aspects. Therefore, studies are currently ongoing towards newer approaches such as lentiviral transmitted enzyme replacement therapy and reprogrammed stem cell-based gene therapy.

Genetics of 46,XY gonadal dysgenesis

In 46,XY men, testis is determined by a genetic network(s) that both promotes testis formation and represses ovarian development. Disruption of this process results in a lack of testis-determination and affected individuals present with 46,XY gonadal dysgenesis (GD), a part of the spectrum of Disorders/Differences of Sex Development/Determination (DSD). A minority of all cases of GD are associated with pathogenic variants in key players of testis-determination, SRY, SOX9, MAP3K1 and NR5A1. However, most of the cases remain unexplained. Recently, unbiased exome sequencing approaches have revealed new genes and loci that may cause 46,XY GD. We critically evaluate the evidence to support causality of these factors and describe how functional studies are continuing to improve our understanding of genotype-phenotype relationships in genes that are established causes of GD. As genomic data continues to be generated from DSD cohorts, we propose several recommendations to help interpret the data and establish causality.

Translational aspects of novel findings in genetics of male infertility-status quo 2021

INTRODUCTION

Male factor infertility concerns 7-10% of men and among these 40-60% remain unexplained.

SOURCES OF DATA

This review is based on recent published literature regarding the genetic causes of male infertility.

AREAS OF AGREEMENT

Screening for karyotype abnormalities, biallelic pathogenic variants in the CFTR gene and Y-chromosomal microdeletions have been routine in andrology practice for >20 years, explaining ~10% of infertility cases. Rare specific conditions, such as congenital hypogonadotropic hypogonadism, disorders of sex development and defects of sperm morphology and motility, are caused by pathogenic variants in recurrently affected genes, which facilitate high diagnostic yield (40-60%) of targeted gene panel-based testing.

AREAS OF CONTROVERSY

Progress in mapping monogenic causes of quantitative spermatogenic failure, the major form of male infertility, has been slower. No 'recurrently' mutated key gene has been identified and worldwide, a few hundred patients in total have been assigned a possible monogenic cause.

GROWING POINTS

Given the high genetic heterogeneity, an optimal approach to screen for heterogenous genetic causes of spermatogenic failure is sequencing exomes or in perspective, genomes. Clinical guidelines developed by multidisciplinary experts are needed for smooth integration of expanded molecular diagnostics in the routine management of infertile men.

AREAS TIMELY FOR DEVELOPING RESEARCH

Di-/oligogenic causes, structural and common variants implicated in multifactorial inheritance may explain the 'hidden' genetic factors. It is also critical to understand how the recently identified diverse genetic factors of infertility link to general male health concerns across lifespan and how the clinical assessment could benefit from this knowledge.

Genetics of human sexual development and related disorders

PURPOSE OF REVIEW

The aim of this study was to provide a basic overview on human sex development with a focus on involved genes and pathways, and also to discuss recent advances in the molecular diagnostic approaches applied to clinical workup of individuals with a difference/disorder of sex development (DSD).

RECENT FINDINGS

Rapid developments in genetic technologies and bioinformatics analyses have helped to identify novel genes and genomic pathways associated with sex development, and have improved diagnostic algorithms to integrate clinical, hormonal and genetic data. Recently, massive parallel sequencing approaches revealed that the phenotype of some DSDs might be only explained by oligogenic inheritance.

SUMMARY

Typical sex development relies on very complex biological events, which involve specific interactions of a large number of genes and pathways in a defined spatiotemporal sequence. Any perturbation in these genetic and hormonal processes may result in atypical sex development leading to a wide range of DSDs in humans. Despite the huge progress in the understanding of molecular mechanisms underlying DSDs in recent years, in less than 50% of DSD individuals, the genetic cause is currently solved at the molecular level.

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.

Broad-spectrum XX and XY gonadal dysgenesis in patients with a homozygous L193S variant in PPP2R3C

CONTEXT

Homozygous and heterozygous variants in PPP2R3C are associated with syndromic 46,XY complete gonadal dysgenesis (Myo-Ectodermo-Gonadal Dysgenesis (MEGD) syndrome), and impaired spermatogenesis, respectively. This study expands the role of PPP2R3C in the aetiology of gonadal dysgenesis (GD).

METHOD

We sequenced the PPP2R3C gene in four new patients from three unrelated families. The clinical, laboratory, and molecular characteristics were investigated. We have also determined the requirement for Ppp2r3c in mice (C57BL6/N) using CRISPR/Cas9 genome editing.

RESULTS

A homozygous c.578T>C (p.L193S) PPP2R3C variant was identified in one 46,XX girl with primary gonadal insufficiency, two girls with 46,XY complete GD, and one undervirilised boy with 46,XY partial GD. The patients with complete GD had low gonadal and adrenal androgens, low anti-Müllerian hormone, and high follicle-stimulating hormone and luteinizing hormone concentrations. All patients manifested characteristic features of MEGD syndrome. Heterozygous Ppp2r3c knockout mice appeared overtly normal and fertile. Inspection of homozygous embryos at 14.5, 9.5, and 8.5 days post coitum(dpc) revealed evidence of dead embryos. We conclude that loss of function of Ppp2r3c is not compatible with viability in mice and results in embryonic death from 7.5 dpc or earlier.

CONCLUSION

Our data indicate the essential roles for PPP2R3C in mouse and human development. Germline homozygous variants in human PPP2R3C are associated with distinctive syndromic GD of varying severity in both 46,XY and 46,XX individuals.

A Novel WT1 Mutation Identified in a 46,XX Testicular/Ovotesticular DSD Patient Results in the Retention of Intron 9

Simple Summary

Disorders/differences of sexual development are very diverse. Among them is a condition characterized by the presence of testicular tissue in people with female chromosomes, which is typically manifested by male or ambiguous genitalia. While genetic counseling is beneficial for these people and their families, the genetic causes of these cases are only partially understood. We describe a new mutation in the WT1 gene that results in the presence of testicular tissue in a child with a female karyotype. We propose molecular mechanisms disrupted by this mutation. This finding widened our understanding of processes that govern sexual development and can be used to develop diagnostic tests for disorders/differences of sexual development.

Abstract

The 46,XX testicular DSD (disorder/difference of sexual development) and 46,XX ovotesticular DSD (46,XX TDSD and 46,XX OTDSD) phenotypes are caused by genetic rearrangements or point mutations resulting in imbalance between components of the two antagonistic, pro-testicular and pro-ovarian pathways; however, the genetic causes of 46,XX TDSD/OTDSD are not fully understood, and molecular diagnosis for many patients with the conditions is unavailable. Only recently few mutations in the WT1 (WT1 transcription factor; 11p13) gene were described in a group of 46,XX TDSD and 46,XX OTDSD individuals. The WT1 protein contains a DNA/RNA binding domain consisting of four zinc fingers (ZnF) and a three-amino acid (KTS) motif that is present or absent, as a result of alternative splicing, between ZnF3 and ZnF4 (±KTS isoforms). Here, we present a patient with 46,XX TDSD/OTDSD in whom whole exome sequencing revealed a heterozygous de novo WT1 c.1437A>G mutation within an alternative donor splice site which is used for −KTS WT1 isoform formation. So far, no mutation in this splice site has been identified in any patient group. We demonstrated that the mutation results in the retention of intron 9 in the mature mRNA of the 46,XX TDSD/OTDSD patient. In cases when the erroneous mRNA is translated, exclusively the expression of a truncated WT1 +KTS protein lacking ZnF4 and no −KTS protein occurs from the mutated allele of the patient. We discuss potential mechanisms and pathways which can be disturbed upon two conditions: Absence of Zn4F and altered +KTS/−KTS ratio.

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.

Molecular and Cytogenetic Analysis of Romanian Patients with Differences in Sex Development

Differences in sex development (DSD) are often correlated with a genetic etiology. This study aimed to assess the etiology of DSD patients following a protocol of genetic testing. Materials and methods. This study prospectively investigated a total of 267 patients with DSD who presented to Clinical Emergency Hospital for Children Cluj-Napoca between January 2012 and December 2019. Each patient was clinically, biochemically, and morphologically evaluated. As a first intervention, the genetic test included karyotype + SRY testing. A high value of 17-hydroxyprogesterone was found in 39 patients, in whom strip assay analysis of the CYP21A2 gene was subsequently performed. A total of 35 patients were evaluated by chromosomal microarray technique, and 22 patients were evaluated by the NGS of a gene panel. Results. The karyotype analysis established the diagnosis in 15% of the patients, most of whom presented with sex chromosome abnormalities. Genetic testing of CYP21A2 established a confirmation of the diagnosis in 44% of patients tested. SNP array analysis was particularly useful in patients with syndromic DSD; 20% of patients tested presented with pathogenic CNVs or uniparental disomy. Gene panel sequencing established the diagnosis in 11 of the 22 tested patients (50%), and the androgen receptor gene was most often involved in these patients. The genes that presented as pathogenic or likely pathogenic variants or variants of uncertain significance were RSPO1, FGFR1, WT1, CHD7, AR, NIPBL, AMHR2, AR, EMX2, CYP17A1, NR0B1, GNRHR, GATA4, and ATM genes. Conclusion. An evaluation following a genetic testing protocol that included karyotype and SRY gene testing, CYP21A2 analysis, chromosomal analysis by microarray, and high-throughput sequencing were useful in establishing the diagnosis, with a spectrum of diagnostic yield depending on the technique (between 15 and 50%). Additionally, new genetic variants not previously described in DSD were observed.

Expanding the spectrum of syndromic PPP2R3C-related XY gonadal dysgenesis to XX gonadal dysgenesis

Homozygous variants in PPP2R3C have been reported to cause a syndromic 46,XY complete gonadal dysgenesis phenotype with extragonadal manifestations (GDRM, MIM# 618419) in patients from four unrelated families, whereas heterozygous variants have been linked to reduced fertility with teratozoospermia (SPGF36, MIM# 618420) in male carriers. We present eight patients from four unrelated families of Turkish and Indian descent with three different germline homozygous PPP2R3C variants including a novel in-frame duplication (c.639_647dupTTTCTACTC, p.Ser216_Tyr218dup). All patients exhibit recognizable facial dysmorphisms allowing gestalt diagnosis. In two 46,XX patients with hypergonadotropic hypogonadism and nonvisualized gonads, primary amenorrhea along with absence of secondary sexual characteristics and/or unique facial gestalt led to the diagnosis. 46,XY affected individuals displayed a spectrum of external genital phenotypes from ambiguous genitalia to complete female. We expand the spectrum of syndromic PPP2R3C-related XY gonadal dysgenesis to both XY and XX gonadal dysgenesis. Our findings supported neither ocular nor muscular involvement as major criteria of the syndrome. We also did not encounter infertility problems in the carriers. Since both XX and XY individuals were affected, we hypothesize that PPP2R3C is essential in the early signaling cascades controlling sex determination in humans.

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.

Ovotesticular Disorder of Sex Development: Approach and Management of an Index Case in the Dominican Republic

Disorders of sex development (DSD) are a group of congenital conditions associated with anomalous development of internal and external genital organs. Ovotesticular disorder of sex development (OT-DSD) is a condition in which a child is born with both testicular tissue (that possesses variable fertility potential within seminiferous tubules) and ovarian tissue (with primordial follicles). These tissues may be co-existent in the same gonad (ovotestis) or independently in separate gonads.

Here, we report the clinical case of a 21-month-old boy that we met during a humanitarian surgical mission performed at Hospital Dr. Francisco Moscoso Puello, Santo Domingo, Dominican Republic. The child was referred for management of hypospadias, cryptorchidism, and symptomatic right inguinal and umbilical hernias. With further chromosomal evaluation, the diagnosis of SRY-negative OT-DSD was made, and shared decision-making was used to determine the timing of gender assignment, reconstruction, and the child’s long-term care team.

OT-DSD is an uncommon condition with unclear causes. Once a DSD condition is suspected at birth, a complete investigation should be performed, encompassing a descriptive examination, a basic electrolyte and hormonal profile, genetic assessment, and pelvic ultrasound. Consultation with a multidisciplinary team is warranted, including pediatric urology or pediatric surgery with urologic training, endocrinology, genetics, psychology, pathology, and the patient’s pediatrician at minimum before surgical reconstruction. It is crucial to involve the patient and their family with shared decision-making before surgery or gender assignment.

Towards improved genetic diagnosis of human differences of sex development

Despite being collectively among the most frequent congenital developmental conditions worldwide, differences of sex development (DSD) lack recognition and research funding. As a result, what constitutes optimal management remains uncertain. Identification of the individual conditions under the DSD umbrella is challenging and molecular genetic diagnosis is frequently not achieved, which has psychosocial and health-related repercussions for patients and their families. New genomic approaches have the potential to resolve this impasse through better detection of protein-coding variants and ascertainment of under-recognized aetiology, such as mosaic, structural, non-coding or epigenetic variants. Ultimately, it is hoped that better outcomes data, improved understanding of the molecular causes and greater public awareness will bring an end to the stigma often associated with DSD.

SRY and NR5A1 gene mutation in Algerian children and adolescents with DSD and testicular dysgenesis

Background

In humans, sex determination and differentiation is genetically controlled. Disorders of sex development (DSD) result in anomalies of the development of the external and internal genitalia. Variants in transcription factors such as SRY, NR5A1 and SOX9, can cause changes in gonadal development often associated with ambiguity of the external genitalia.

Objectives

This study has been conducted to determine the frequency, types and associated genetic alterations in patients with DSD in the Algerian population.

Methods

Thirty patients were included. Based on their clinical presentation, thirteen patients presented with ambiguous external genitalia, thirteen patients presented with hypospadias and four patients presented with bilateral undescended testes. Karyotype analysis was performed on peripheral blood lymphocytes using standard R-banding. DNA was isolated from blood leukocytes for PCR reaction and mutational analysis of SRY and NR5A1 was done by direct sequencing.

Results

Most patients with ambiguous genitalia had a 46,XY karyotype. One patient had a deletion of SRY, otherwise no point mutations in SRY or NR5A1 genes were identified. However, a single NR5A1 polymorphism (p.Gly146Ala) in patient with 46,XX DSD has been detected.

Conclusions

The absence of mutations in these genes suggests that there are others genes playing an important role in sex development and differentiation.