DHX37 and the implications in Disorders of Sex Development: an update review

BACKGROUND

DHX37 is an autosomal gene responsible for encoding a helicase from the DExD/H-box family that plays an essential role in ribosome biogenesis. Variants in this gene were previously reported in two different phenotypes: neurodevelopmental disorders and disorders/differences of sex development (DSD). Particularly for the DSD group, variants were mainly reported associated with gonadal dysgenesis and testicular regression syndrome.

SUMMARY

Focusing specific in the DSD group, we revised the 21 DHX37 variants described across a total of 55 cases published in the literature so far. We summarized the most important clinical and molecular features of all cases, trying to have a better comprehensiveness about this gene in the sexual development.

KEY MESSAGES

The trick question regarding DHX37 is how a helicase involved in basic cell function could have a specific role in testis development. Little is known about the impact of DHX37 variants in DSD individuals. Nevertheless, current research strongly suggests that DHX37 is involved in the male sex development pathway, particularly in testis determination and maintenance. This is evidenced by the predominant assignment of affected individuals as males and the presence of Wolffian structures in most of the cases. Advancements in molecular techniques, such as the generation of induced pluripotent stem cells, and the digenic inheritance for DHX37 cases, are also addressed in this paper. This represents the first comprehensive review of all DHX37 variants published in the literature to date.

Prenatal Findings in Postnatal Cases of Disorders of Sex Development: Experience from a Tertiary-Specialized Center in Brazil

INTRODUCTION AND OBJECTIVE

Prenatal suspicion of disorders/differences of sex development (DSDs) is a relatively new phenomenon. The aim of this study was to review the prenatal findings of DSD cases postnatally diagnosed in our tertiary referral center.

METHODS

We evaluated 57 DSD cases with sex ambiguity who had undergone prenatal ultrasound with phenotypic sex assessment and/or cell-free fetal DNA (cffDNA) for genotypic sex assessment.

RESULTS

Prenatal cffDNA had been performed in 32 cases, being positive (suggestive of male genotypic sex) in 26 and negative (suggestive of female genotypic sex) in 6. Five with cffDNA negative had a prenatal ultrasound indicating female external genitalia, in turn, in those with cffDNA positive, only two had a prenatal ultrasound indicating male external genitalia. Our postnatal data showed that when external genitalia were female or poorly virilized, prenatal ultrasound indicated female sex, but in cases of higher degree of virilization, ultrasound showed similar rates of male, female, or undetermined sex. Regarding the karyotype, our data showed those with XY karyotype had positive cffDNA, those with XX karyotype had negative cffDNA, and all five with sex chromosome anomalies had positive cffDNA because they were 45,X/46,XY. We suggested an algorithm to investigate these cases during gestation, including evaluation of uterus, fetal growth, and malformations.

CONCLUSION

We suggest that the parents should be counseled prenatally by a dedicated multidisciplinary team with experience in DSD management and evaluated as soon as possible after birth.

DHX37 and NR5A1 Variants Identified in Patients with 46,XY Partial Gonadal Dysgenesis

The group of disorders known as 46,XY gonadal dysgenesis (GD) is characterized by anomalies in testis determination, including complete and partial GD (PGD) and testicular regression syndrome (TRS). Several genes are known to be involved in sex development pathways, however approximately 50% of all cases remain elusive. Recent studies have identified variants in DHX37, a gene encoding a putative RNA helicase essential in ribosome biogenesis and previously associated with neurodevelopmental disorders, as a cause of PGD and TRS. To investigate the potential role of DHX37 in disorders of sexual development (DSD), 25 individuals with 46,XY DSD were analyzed and putative pathogenic variants were found in four of them. WES analyses were performed on these patients. In DHX37, the variant p.(Arg308Gln), recurrent associated with DSD, was identified in one patient; the p.(Leu467Val), predicted to be deleterious, was found together with an NR5A1 loss-of-function variant in patient 2; and, the p.(Val999Met) was identified in two unrelated patients, one of whom (patient 3) also carried a pathogenic NR5A1 variant. For both patients carrying DHX37 and NR5A1 pathogenic variants, a digenic inheritance is suggested. Our findings support the importance of DHX37 variants as a cause of disorders of sex development, implying a role in testis development.

Can Non-Coding NR5A1 Gene Variants Explain Phenotypes of Disorders of Sex Development?

INTRODUCTION

NR5A1 is an essential transcription factor that regulates several target genes involved in reproduction and endocrine function. Pathogenic variants in this gene are responsible for a wide spectrum of disorders/differences of sex development (DSD).

METHODS

The molecular study involved Sanger sequencing, in vitro assays, and whole exome sequencing (WES).

RESULTS

Four variants were identified within the NR5A1 non-coding region in 3 patients with 46,XY DSD. In vitro analyses showed that promoter activity was affected in all cases. WES revealed variants in SRA1, WWOX, and WDR11 genes.

DISCUSSION/CONCLUSION

Evaluation of clinical and phenotypic significance of variants located in a non-coding region of a gene can be complex, and little is known regarding their association with DSD. Nevertheless, based on the important region for interaction with cofactors essential to promote appropriated sex development and on our in vitro results, it is feasible to say that an impact on gene expression can be expected and that this may be correlated with the DSD pathophysiology presented in our patients. Considering the number of cases that remain elusive after screening for the well-known DSD related genes, we emphasize the importance of a careful molecular analysis of NR5A1 non-coding region which is commonly neglected and might explain some idiopathic DSD cases.

Are NR5A1 Variations a Frequent Cause of 46,XX Ovotesticular Disorders of Sex Development? Analysis from a Single Center and Systematic Review

INTRODUCTION

Ovotesticular disorder of sex development (OT-DSD) is a rare condition defined by concomitance of testicular tissue and ovarian tissue (containing follicles) in the same individual. In SRY-negative 46,XX OT-DSD, the presence of testicular tissue may be due to variations in NR5A1. Our aims were to search for NR5A1 variants in SRY-negative 46,XX OT-DSD patients and to perform a systematic review on the contribution of NR5A1 variations to 46,XX OT-DSD.

METHODS

Sanger sequencing of NR5A1 was performed in seven SRY-negative 46,XX OT-DSD patients: five simplex cases and two with another sibling with a 46,XX DSD. Systematic review of original studies on NR5A1 sequencing of 46,XX OT-DSD patients was performed according to PRISMA-P guideline. Case reports were selected for analysis of clinical features. Individuals with NR5A1-associated testicular DSD were not included.

RESULTS

Sanger sequencing of NR5A1 did not reveal pathogenic variants among our patients. Our cohort was included in this systematic review with seven other articles, totalizing fifty-six 46,XX OT-DSD patients investigated by Sanger or whole-exome sequencing. From them, three NR5A1 pathogenic variants were identified (5% of the cases). Clinical analysis of these 3 cases and 5 case reports revealed: predominance of ovotestis (13/16 gonads) and bilateral OT-DSD (5/8 cases).

CONCLUSION

The etiology of most 46,XX OT-DSD cases remains elusive, highlighting the importance of a deeper molecular investigation.

Trends in Time Regarding Sex Assignment of Patients with Disorders of Sex Development: Experience of an Interdisciplinary Service

INTRODUCTION

The aim of this retrospective study was to verify the association between the time of diagnosis and initial and final sex assignment in a disorder of sex development (DSD) diagnostic group, looking at the age of the patients at first visit, severity of genital ambiguity, and karyotype.

METHODS

The time of diagnosis was divided into 3 groups: before 2000, between 2000 and 2006, and after 2006. Data were categorized and analyzed using the χ2 test with α < 0.05.

RESULTS

A total of 567 cases were analyzed; 307 were assigned as male, 135 as female, and 125 remained undefined at the first visit. After clinical and laboratory evaluations, 369 patients were male and 198 were female. Neither initial nor final sex assignment proportions changed over time, but there were significant differences in the age at first visit, with referral occurring at an earlier age, as well as more severe genital ambiguity presentations, a higher proportion of sex chromosome aberrations, and a lower frequency of 46,XX DSD cases. This occurred both in the sample as a whole (567 cases) and in the group of 125 patients without definitive sex assignment at the first visit. The results were similar when only 284 patients aged less than 12 months at the first visit were analyzed.

DISCUSSION/CONCLUSION

Over time, there were no changes in sex assignment proportions, but there was an increased awareness of the need for early referral and changes in clinical, cytogenetic, and diagnostic aspects.

A Novel Look at Dosage-Sensitive Sex Locus Xp21.2 in a Case of 46,XY Partial Gonadal Dysgenesis without NR0B1 Duplication

A region of 160 kb at Xp21.2 has been defined as dosage-sensitive sex reversal (DSS) and includes the NR0B1 gene, considered to be the candidate gene involved in XY gonadal dysgenesis if overexpressed. We describe a girl with 46,XY partial gonadal dysgenesis carrying a 297 kb duplication at Xp21.2 upstream of NR0B1 initially detected by chromosomal microarray analysis. Fine mapping of the breakpoints by whole-genome sequencing showed a tandem duplication of TASL (CXorf21), GK and partially TAB3, upstream of NR0B1. This is the first description of an Xp21.2 duplication upstream of NR0B1 associated with 46,XY partial gonadal dysgenesis.

Sex dimorphism of weight and length at birth: evidence based on disorders of sex development

BACKGROUND

Males have higher weight and length at birth than females.

AIM

To verify the influence of the Y chromosome and the action of intrauterine androgens on weight and length at birth of children with Disorders of Sex Development (DSD).

SUBJECTS AND METHODS

A cross-sectional and retrospective study. Patients with Turner syndrome (TS), complete (XX and XY), mixed (45,X/46,XY) and partial (XY) gonadal dysgenesis (GD), complete (CAIS) and partial (PAIS) androgen insensitivity syndromes and XX and XY congenital adrenal hyperplasia (CAH) were included. Weight and length at birth were evaluated.

RESULTS

Weight and length at birth were lower in TS and mixed GD when compared to XY and XX DSD cases. In turn, patients with increased androgen action (117 cases) had higher weight and length at birth when compared to those with absent (108 cases) and decreased (68 cases) production/action. In birthweight, there was a negative influence of the 45,X/46,XY karyotype and a positive influence of increased androgen and gestational age. In birth length, there was a negative influence of the 45,X and 45,X/46,XY karyotypes and also a positive influence of increased androgen and gestational age.

CONCLUSIONS

The sex dimorphism of weight and length at birth could possibly be influenced by intrauterine androgenic action.

MYRF: A New Regulator of Cardiac and Early Gonadal Development—Insights from Single Cell RNA Sequencing Analysis

De novo variants in the myelin regulatory factor (MYRF), a transcription factor involved in the differentiation of oligodendrocytes, have been linked recently to the cardiac and urogenital syndrome, while familiar variants are associated with nanophthalmos. Here, we report for the first time on a patient with a de novo stop-gain variant in MYRF (p.Q838*) associated with Scimitar syndrome, 46,XY partial gonadal dysgenesis (GD) and severe hyperopia. Since variants in MYRF have been described in both 46,XX and 46,XY GD, we assumed a role of MYRF in the early development of the bipotential gonad. We used publicly available single cell sequencing data of human testis and ovary from different developmental stages and analysed them for MYRF expression. We identified MYRF expression in the subset of coelomic epithelial cells at stages of gonadal ridge development in 46,XX and 46,XY individuals. Differential gene expression analysis revealed significantly upregulated genes. Within these, we identified CITED2 as a gene containing a MYRF binding site. It has been shown that Cited2^−/− mice have gonadal defects in both testis and ovary differentiation, as well as defects in heart development and establishment of the left–right axis. This makes MYRF a potential candidate as an early regulator of gonadal and heart development via upregulation of the transcriptional cofactor CITED2.

So, and if it is not congenital adrenal hyperplasia? Addressing an undiagnosed case of genital ambiguity

Background

The Congenital Adrenal Hyperplasia due to 21 hydroxylase deficiency is the most common cause of genital ambiguity in persons with XX sexual chromosomes. Genital ambiguity among persons with XY sexual chromosomes comprises diverse and rare etiologies. The deficiency of 17-beta-hydroxysteroid dehydrogenase type 3 enzyme (HSD17B3) is a rare autosomal recessive disorder due to functionally altered variants of the HSD17B3 gene. In this disorder/difference of sex development, the conversion of androstenedione into testosterone is impaired. The appearance of external genitalia of 46,XY individuals varies from typically male to almost female.

Case presentation

We report on a child presenting severe ambiguous genitalia. Due to access constraints, specialized care did not start until the child was 10 months old. Parents are consanguineous and were born in an area of high isonymy that is a cluster for rare recessive diseases. A new homozygous missense variant c.785G > T was found in exon 10 of the HSD17B3 gene.

Conclusions

Researchers-clinicians and researchers-researchers collaborative efforts to elucidate the genetic basis of this disease were critical since this etiologic investigation is not available through the public health system. This case exemplifies the families’ pilgrimage in cases of genital ambiguity due to a rare genetic condition. Recognizing the etiology was the baseline to provide information on prognosis and treatment options, and to shelter family and child doubts and hopes in order to better support their decisions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13052-022-01284-9.

Clinical and laboratory differences between chromosomal and undefined causes of non-obstructive azoospermia: A retrospective study

BACKGROUND

Knowledge of clinical and laboratory differences between chromosomal and undefined causes aids etiological research on non-obstructive azoospermia.

OBJECTIVE

Compare clinical and laboratory differences between men with non-obstructive azoospermia due to chromosomal anomalies versus undefined causes.

DESIGN AND SETTING

A cross-sectional retrospective study conducted at a public university hospital in Campinas (Brazil).

METHODS

All men aged 20-40 years with non-obstructive azoospermia were included in the analysis.

RESULTS

The 107 cases included 14 with Klinefelter syndrome (KS) (13%), 1 with mosaic KS, 4 with sex development disorders (2 testicular XX, 1 NR5A1 gene mutation, and 1 mild androgen insensitivity syndrome) (4%), 9 with other non-obstructive azoospermia etiologies (8%), and 79 with undefined causes. The 22 chromosomal anomaly cases (14 KS, 1 mosaic KS, 2 testicular XX, 4 sex chromosome anomalies, and 1 autosomal anomaly) were compared with the 79 undefined cause cases. The KS group had lower average testicular volume, shorter penile length, and lower total testosterone levels but greater height, arm span, serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels, and gynecomastia frequency (absent in the undefined group and affecting more than half of the KS group). Patients with testicular XX DSD had LH, FSH, and penile length data intermediate between the KS and undefined cause groups, testicular volume similar to the KS group, and other data similar to the undefined group.

CONCLUSION

Clinical and laboratory data differentiate men with non-obstructive azoospermia and chromosomal anomalies, particularly KS and testicular XX, from those with undefined causes or other chromosomal anomalies.

Association between Down Syndrome and Disorders of Sex Development: Report of Three Cases and Review of 188 Cases in the Literature

In this study, we present 3 cases of Down syndrome (DS) associated with disorders/differences of sex development (DSD) and review the literature on this topic. Case 1: 1-year-old child with male genitalia and DS phenotype, 47,XX,+21 karyotype and testicular DSD. Case 2: 11-month-old child with male genitalia and few DS dysmorphisms, 45,X/47,XY,+21 karyotype, and mixed gonadal dysgenesis. Case 3: 4-month-old child with female genitalia and DS phenotype, 47,XY,+21 karyotype and XY complete gonadal dysgenesis. In the literature, among 188 patients, 107 (57%) had Klinefelter syndrome and 61 (33%) Turner syndrome, 12 (6%) had mixed gonadal dysgenesis, 2 (1%) had partial androgen insensitivity, 2 (1%) ovotesticular DSD, and the others had congenital adrenal hyperplasia, XY partial gonadal dysgenesis, XY complete gonadal dysgenesis, and complete androgen insensitivity (1 case each). A typical DS phenotype was found in all individuals of the revision, with the exception of one case, but DSD features were not always reported. In conclusion, the association of DS with sex chromosome DSD is the most frequently observed, whereas associations with 46,XX and 46,XY DSD is extremely rare.

Why pediatricians need to know the disorders of sex development: experience of 709 cases in a specialized service

OBJECTIVE

To evaluate, in a sample of patients with disorders of sex development (DSD), data related to the age at referral and their correlation with the initial complaints, gender at referral, defined gender after diagnosis and etiological diagnosis.

METHODS

Retrospective review of the age at the first consultation and the reason for it, initial social gender and gender after the diagnosis, karyotype and etiological diagnosis of all cases treated at a DSD outpatient clinic between 1989 and 2016. Cases that did not involve DSD and DSD diagnoses that do not usually involve ambiguous genitalia, thus not requiring specialized monitoring, were excluded.

RESULTS

Of the 1793 treated cases, 1139 were diagnosed with some type of DSD. This study excluded 430 cases (272 with Turner's syndrome, 66 with Klinefelter syndrome, and 92 with pure gonadal dysgenesis), thus a total 709 individuals were included. Of these, 82.9% were referred due to ambiguous genitalia; only one-quarter were still in the first month of life, and 6.6% were referred due to pubertal delay, with most of them aged 10 years or older. Of these patients, 68.6% had a diagnosis of XY DSD, 22.4% of XX DSD, and 9% of sex chromosome abnormalities.

CONCLUSIONS

This study presents the largest series in the literature of patients with DSD treated in a single center. The time of referral of the majority of patients with ambiguous genitalia fell short of the ideal, and milder cases of ambiguous genitalia and many with pubertal manifestations were referred even later. The results reinforce the importance of continuing education for professionals who will have the first contact with these patients, mainly pediatricians and neonatologists.

SUN-086 Pilot Study Using Aromatase Inhibitor in Puberty of Boys With Partial Androgen Insensitivity: Report of Three Cases

Background: Partial Androgen Insensitivity Syndrome (PAIS) (OMIM # 312300) is one of the causes of Disorders/Differences of Sex Development with 46,XY karyotype and normal or increased testosterone secretion that results in atypical genitalia. In general, it is caused by inactivating mutations on AR gene (Xq12 - OMIM * 313700), therefore it presents an X-linked recessive inheritance. Individuals raised as males have incomplete puberty with micropenis, sparse hairs, gynecomastia and increased LH, testosterone and estradiol serum levels. Therefore, the use of aromatase inhibitor in these cases becomes a logical indication aiming to increase testosterone levels in the tentative of supplanting its peripheral resistance and decreasing estrogen levels. Objective: To present clinical and laboratory data during the first year of use of aromatase inhibitor in puberty of three boys with confirmed molecular diagnosis of PAIS. Results: All subjects used letrozole (2.5 mg daily during 12 months). None reported significant side effects. Cases 1 and 2 are brothers (p.Ala596Tre). Case 1: Onset of treatment at age 12; height changed from 158 cm (z = +1.15) to 166 cm (z = +1.21), Tanner from G2P2T2 to G3P3T1, penis from 4.0 to 6.5 cm, LH from 7.5 to 18.3 IU/L (NR: 1.5 to 9.3 IU/L), testosterone from 361 to 1,347 ng/dL (NR: 165 to 763 ng/dL), estradiol from 35 to <5.0 pg/mL (NR: < 40 pg/mL) and bone age remained at 13 years. Case 2: Onset of treatment at age 11; height changed from 156 cm (z = +1.71) to 163 cm (z = +1.80), Tanner from G2P2T2 to G3P3T1, penis from 3.5 to 5.5 cm, LH from 4.8 to 12.4 IU/L (NR: 1.5 to 9.3 IU/L), testosterone from 259 to 1,069 ng/dL (NR: 165 to 763 ng/dL), estradiol from 28 to <5.0 pg/mL (NR: < 40 pg/mL) and bone age remained at 12.5 years. Case 3 (p.Ser597Arg): Onset of treatment at age 12; height changed from 153 cm (z = +0.49) to 161 cm (z = +0.55), Tanner from G2P2T1 to G3P3T1, penis from 4.0 to 7.0 cm, LH from 8.5 to 17.2 IU/L (NR: 1.5 to 9.3 IU/L), testosterone from 280 to 889 ng/dL (NR: 165 to 763 ng/dL), estradiol from 32 to <5.0 pg/mL (NR: < 40 pg/mL) and bone age remained at 13.5 years. Discussion: There are no reports in the literature of the use of aromatase inhibitor in PAIS. The results of this pilot study (gynecomastia regression, significant testosterone level increases with decrease in estradiol levels, increment in height without bone age advancing, progression of puberty and penile growth) are sustaining for the indication of this treatment in boys with PAIS during puberty.

MON-056 Rare X Chromosome Pericentric Inversion Associated with Ovotesticular Disorder of Sex Development

Ovotesticular disorder of sex development (OT-DSD) is a rare condition characterized by coexistence of ovarian and testicular parenchyma, in separate gonads or in the same gonad (ovotestis), in individuals with variable degrees of genital ambiguity. Karyotype may be 46,XX (60%), 46,XY (10%), or there may be sex chromosomes abnormalities, including mosaicism, chimerism and structural anomalies (30%). A genetic origin may be identified in some subjects with normal XX or XY karyotype, but most cases are of unknown origin. Apparently balanced chromosome rearrangements (translocations, insertions and inversions) may cause truncation, deletion, inactivation or over-expression of specific genes. We report on a case of OT-DSD associated with an X chromosome inversion. Case report: A 3-month old girl was referred due to atypical genitalia. She was born at term to a 42 years old G3P2A1 mother and her 45 years old unrelated husband with normal weight, length and head circumference. She had normal development, no associated health problems, and family history was unremarkable. Physical examination revealed a 3.1-cm phallus with chordee, scrotal hypospadias, partial penoscrotal inversion and a 0.5 cm³ right gonad palpable in the inguinal region; there were no associated dysmorphic features. At 1.5 months there were normal levels of FSH (3.09 IU/L) and LH (3.67 IU/L), and testosterone (155 ng/dL) was in the normal male range. Ultrasound revealed normal uterus and gonads were in the inguinal regions. Urethra-cystoscopy and vaginoscopy at 9 months revealed a urogenital sinus with high vaginal confluence. Laparoscopy and gonadal biopsies were also performed; the left gonad was an ovotestis with multiple ovarian follicles, while the right gonad was a testis. In both gonads the seminiferous tubules had only Sertoli cells. Karyotype revealed a pericentric X chromosome inversion, 46,X,inv(X)(p22.1q26)dn[20]. FISH on peripheral blood and cultured cells from the right gonad with probes for X (DXZ1) and Y (DYZ3) centromeres and SRY (Yp11.3 - 122 Kb) showed only two X chromosome signals. Array GH analysis (Cytoscan 750K, Affymetrix) showed a 1.3 Mb deletion distal to the short arm breakpoint (Xp22.31), which was reported as VOUS, and a 9 Mb region of LOH on chromosome 9. Discussion: Several cases of X pericentric inversion with different breakpoints have been reported; though phenotypes of female heterozygotes are often normal, early menopause, irregular menses, gonadal dysgenesis or sterility have been described. In this case, it is plausible that the genomic rearrangement could have affected long-range regulation of SOX3 (located in Xq27.1) resulting in ectopic expression of this gene in the bipotential gonad. In addition, the features detected in array GH may have a role in the phenotype. Different methods to determine the exact chromosomal breakpoints and copy number variations in this region will be required.

A Search for Disorders of Sex Development among Infertile Men

A retrospective cross-sectional study was performed in a DSD clinic at a tertiary service (University Hospital) to estimate the frequency of disorders of sex development (DSD) among men who seek medical care because of infertility. The sample included 84 men >20 years of age referred from 2010-2017 due to oligozoospermia or nonobstructive azoospermia of unknown etiology. Twelve cases (14%) were diagnosed as DSD, including Klinefelter Syndrome, 46,XX testicular DSD, and mild androgen insensitivity syndrome. Y chromosome microdeletions were detected in 2 patients. Among the remaining 70 cases there were patients with chromosome abnormalities which are not included in the DSD classification as well as rare NR5A1 variants of uncertain significance and hypergonadotropic hypogonadism and microorchidism in 46,XY subjects. In conclusion, the frequency of DSD in this study was 14%, consisting mainly of sex chromosome abnormalities but also 46,XX and 46,XY DSD. However, this figure may increase as further investigations are conducted in idiopathic cases with signs of primary testicular failure, which may present partial gonadal dysgenesis.