XY DSD Research Articles

Genetic diagnosis in XY disorders of sex development

XY disorders of sex development (XY DSD) comprise a class of heterogeneous genetic entities that result in discrepancies between chromosomal, gonadal, and phenotypic sex due to a reduction in androgen synthesis or action. The chief categories of disorders include gonadal dysgenesis, disorders with reduced androgen production (biosynthetic defect – either alone or in conjunction with impaired glucocorticoid and/or mineralocorticoid synthesis), and insensitivity to androgen action. While conventional diagnostic modalities, encompassing karyotyping, biochemistry, radiology, and, in a few cases, diagnostic laparoscopy, help in formulating a provisional diagnosis, molecular genetic testing is key to arriving at a precise etiology. Besides ending the diagnostic uncertainty, a molecular diagnosis helps to predict the natural course in terms of pubertal development and potential for fertility, thus contributing to decisions on the gender of rearing; and guides on surveillance for extragenital features and the risk of recurrence in subsequent pregnancies. This paper broadly discusses the genetic basis of XY DSD, different modalities of genetic testing, and their utility and limitations.

7772 A Study on Role of Anti-Mullerian Hormone and Inhibin B in 46,XY Disorders Of Sexual Development

Abstract Disclosure: N. Kudugunti: None. S. Bangaru: None. R.K. Sahay: None. Background: In pre-pubertal period, a major part of the testicular tissue is constituted by Sertoli cells for which AMH, Inhibin B are specific biomarkersHigh AMH, Inhibin B levels in the prepubertal period is via FSH stimulation, which is mistakenly considered to be silent due to its reduced activity Aim & Objectives: To assess AMH and Inhibin B measurements in the diagnostic workup of prepubertal children with different subtypes of 46,XY DSD and comparing with normal controls To assess Sertoli cell function with AMH and Inhibin B and to assess correlation between testosterone elevation after hCG stimulation, basal AMH and Inhibin B Patients and methods: Pilot study-Single centered, Cross-sectional Observational study. After ethical committee approval, 40 children with 46,XY DSD & 40 healthy age matched, boys as controls recruited after taking assent. All children with DSD underwent karyotyping, assessment of hCG stimulated testosterone, DHT and androstenedione. Basal AMH and inhibin B were measured in both cases and controls. Data were analysed using IBM SPSS version 25. Results: The mean age at presentation was 4.09 years.The diagnosis was made clinically and biochemically, genetic analysis done in few patients. Out of 40 cases, 26 had normal hCG stimulated testosterone of >100 ng/dl (17 cases were 5 alpha reductase type 2 deficiency [5αR2D], 9 cases were PAIS) & 14 had low hCG stimulated testosterone of <100 ng/dl (8 cases were 17βHSD3 deficiency, 4 cases were Partial gonadal dysgenesis [PGD], 2 cases were Vanishing testis syndrome). In the low testosterone group, mean AMH in 17βHSD3 deficiency-279.95 ng/ml, in PGD-31.16 ng/ml which is statistically significant in differentiating these disorders(p-0.002)& mean Inhibin B in 17βHSD3 deficiency-186.41 pg/ml, in PGD-35.95 pg/ml which is statistically significant in differentiating these disorders (p-0.007). In vanishing testis syndrome, AMH & Inhibin B were helpful in confirming the absent functioning testicular tissue Whereas in normal testosterone group, mean AMH in PAIS-235.65 ng/ml, in 5αR2D-289.08 ng/ml difference is not statistically significant(p-0.36)& mean Inhibin B in PAIS-204.50 pg/ml, in 5αR2D-190.91 pg/ml difference is not statistically significant(p-0.72) There was significant correlation between basal AMH and hCG stimulated testosterone (r=0.434; p-0.002), Inhibin B and hCG stimulated testosterone(r=0.438; p-0.001), AMH and Inhibin B(r=0.770; p<0.001). Conclusion: AMH and Inhibin B are valuable in differentiating PGD, 17βHSD3 deficiency in low hCG stimulated testosterone patients, but not helpful in differentiating PAIS, 5αR2D in normal hCG stimulated testosterone patients. Especially in PGD they may have a role with respect to fertility prospects and malignancy risk assessment. Presentation: 6/3/2024

Application and insights of targeted next-generation sequencing in a large cohort of 46,XY disorders of sex development in Chinese

Purpose46,XY disorders of sex development (46,XY DSD) are characterized by incomplete masculinization of genitalia with reduced androgenization. Accurate clinical management remains challenging, especially based solely on physical examination. Targeted next-generation sequencing (NGS) with known pathogenic genes provides a powerful tool for diagnosis efficiency. This study aims to identify the prevalent genetic variants by targeted NGS technology and investigate the diagnostic rate in a large cohort of 46,XY DSD patients, with most of them presenting atypical phenotypes.MethodsTwo different DSD panels were developed for sequencing purposes, targeting a cohort of 402 patients diagnosed with 46,XY DSD, who were recruited from the Department of Urology at Children’s Hospital, Zhejiang University School of Medicine (Hangzhou, China). The detailed clinical characteristics were evaluated, and peripheral blood was collected for targeted panels to find the patients’ variants. The clinical significance of these variants was annotated according to American College of Medical Genetics and Genomics (ACMG) guidelines.ResultsA total of 108 variants across 42 genes were found in 107 patients, including 46 pathogenic or likely pathogenic variants, with 45.7%(21/46) being novel. Among these genes, SRD5A2, AR, FGFR1, LHCGR, NR5A1, CHD7 were the most frequently observed. Besides, we also detected some uncommon causative genes like SOS1, and GNAS. Oligogenic variants were also identified in 9 patients, including several combinations PROKR2/FGFR1/CYP11B1, PROKR2/ATRX, PROKR2/AR, FGFR1/LHCGR/POR, FGFR1/NR5A1, GATA4/NR5A1, WNT4/AR, MAP3K1/FOXL2, WNT4/AR, and SOS1/FOXL2.ConclusionThe overall genetic diagnostic rate was 11.2%(45/402), with an additional 15.4% (62/402) having variants of uncertain significance. Additionally, trio/duo patients had a higher genetic diagnostic rate (13.4%) compared to singletons (8.6%), with a higher proportion of singletons (15.1%) presenting variants of uncertain significance. In conclusion, targeted gene panels identified pathogenic variants in a Chinese 46,XY DSD cohort, expanding the genetic understanding and providing evidence for known pathogenic genes’ involvement.

Evidence for NR2F2/COUP-TFII involvement in human testis development

NR2F2 encodes COUP-TFII, an orphan nuclear receptor required for the development of the steroidogenic lineages of the murine fetal testes and ovaries. Pathogenic variants in human NR2F2 are associated with testis formation in 46,XX individuals, however, the function of COUP-TFII in the human testis is unknown. We report a de novo heterozygous variant in NR2F2 (c.737G > A, p.Arg246His) in a 46,XY under-masculinized boy with primary hypogonadism. The variant, located within the ligand-binding domain, is predicted to be highly damaging. In vitro studies indicated that the mutation does not impact the stability or subcellular localization of the protein. NR5A1, a related nuclear receptor that is a key factor in gonad formation and function, is known to physically interact with COUP-TFII to regulate gene expression. The mutant protein did not affect the physical interaction with NR5A1. However, in-vitro assays demonstrated that the mutant protein significantly loses the inhibitory effect on NR5A1-mediated activation of both the LHB and INSL3 promoters. The data support a role for COUP-TFII in human testis formation. Although mutually antagonistic sets of genes are known to regulate testis and ovarian pathways, we extend the list of genes, that together with NR5A1 and WT1, are associated with both 46,XX and 46,XY DSD.

A novel mutation in a case of XY DSD with progressive virilization at puberty

ABSTRACT We present a case of ambiguous genitalia, not being evaluated at birth and presenting with progressive virilization at puberty. The usual set of differential diagnoses in a patient with the presence of bilateral gonads and progressive virilization includes five alpha-reductase deficiency, 17 beta-hydroxysteroid dehydrogenase 3 deficiency, partial androgen insensitivity syndrome, and partial gonadal dysgenesis. Human chorionic gonadotropin (HCG) stimulation test performed on our patient suggested the presence of five alpha-reductase deficiency with a testosterone/dihydrotestosterone (T/DHT) ratio of 32; however, the genetic analysis revealed the presence of autosomal dominant, heterozygous pathogenic mutation in NR5A1 gene Exon 5 with autosomal dominant heterozygous mutation in DHX37 gene Exon 18. While NR5A1 mutation is a known cause of testicular dysgenesis; DHX37 is a novel gene associated with ambiguous genitalia and there are only a few case reports presenting with a combined mutation. The patient exhibited a high T/DHT ratio on HCG stimulation and also exhibited poor virilization despite being on testosterone therapy for 2 years. Whether these mutations affect five alpha-reductase enzymes inhibiting testosterone to dihydrotestosterone conversion is unknown.

Laparoscopy versus ultrasonography for the evaluation of Müllerian duct remnants in male patients with disorder of sex differentiation

BackgroundThe diagnosis of male differences of sex development is a challenging multidisciplinary team task, that requires external genital evaluation, karyotyping, hormonal profiling, radiological work up and frequently diagnostic laparoscopy and biopsy, for evaluation of internal duct system and nature of gonads. The debate still persists regarding the best diagnostic modality for accurate visualization of Müllerian duct remnants (MDRs) in those patients.The aim of the study was to compare between laparoscopy (L) and ultrasonography (US) regarding the diagnostic accuracy in detection of Müllerian duct remnants, in addition to describing their anatomical nature and relations with the male duct system, in patients with male DSD, with various karyotypes.MethodsWe prospectively included 20 patients with male DSD, mostly due to 46 XY DSD or chromosomal DSD, over 2 years. The medical and radiological data were collected and analyzed.ResultsThe age at the first diagnostic intervention ranged from 8 to 24 months (mean: 17 months). There were 14 patients with 46XY DSD with variable diagnoses (3 ovotesticular DSD, 3 partial gonadal dysgenesis, 6 persistent Müllerian duct remnants syndrome and 2 mixed gonadal dysgenesis). Two patients with 46XX DSD were included (one XX male, and one patient with ovotesticular DSD). One patient with chimerism (46XY/46XX) and three patients with 46XY/45XO mixed gonadal dysgenesis were also recruited. MDRs were evident in all cases (100%) by laparoscopy, only 25% (n = 5) were visualized by US. There was a statistically significant difference between laparoscopy and US regarding gonadal and MDR visualization, being higher with laparoscopy (p values, 0.0180 and 0.001).ConclusionsUltrasonography failed to visualize Müllerian remnants in 75% of patients with complex DSD. On the other hand, laparoscopy provided optimum visualization of MDRs and gonads in those children.

Sex Reassignment Dilemma in 4 Yemeni Siblings with Five Alpha-Reductase Type 2 Deficiency

5α-Reductase two deficiency (5αR2D) is an autosomal recessive 46, XY disorder impacting the HeRD5A2 gene, causing ambiguous genitalia. Four Yemeni siblings with this condition sought guidance from the Sudanese Intersex Working Group (SIWG) in adulthood. A multidisciplinary evaluation was conducted, encompassing physical, mental, hormonal, and imaging examinations, although genetic mutation analysis of the srd5a2 gene was precluded due to limited facilities. Participants were initially assigned as females by an untrained birth attendant; the siblings later manifested virilisation before puberty, prompting a reassignment to the male sex. Despite presenting with 46 XY DSD due to 5αR2D, their sexual identity conflict led them to seek counsel from the SIWG. Comprehensive assessments confirmed the 5αR2D diagnosis. Extensive counselling with the family revealed their resolute decision to maintain the male sex despite concerns highlighted by the SIWG regarding future sexual function and fertility. This case underscores the significant challenges stemming from inadequate knowledge and interventions, emphasising the critical need for early diagnosis, proper genetic counselling, and expert management. Timely referrals to specialised facilities and consideration of options such as in vitro fertilisation (IVF) and preimplantation genetic diagnosis (PGD) for subsequent children are imperative. This report advocates for proactive measures in similar cases, emphasising the importance of tertiary care facilities for accurate diagnosis, informed decision-making, and optimal management of 5αR2D-related dilemmas.

Novel association of NUP107 variants in XY DSD

Novel association of NUP107 variants in XY DSD

45,X/46,XY DSD with gender dysphoria: the conundrum around pubertal induction

45,X/46,XY DSD with gender dysphoria: the conundrum around pubertal induction

The value of the stimulated testosterone: dihydrotestosterone ratio in 46, XY DSD due to 5alpha-reductase type 2 deficiency

The value of the stimulated testosterone: dihydrotestosterone ratio in 46, XY DSD due to 5alpha-reductase type 2 deficiency

Human Rights in Sports Arbitration: What Should the Court of Arbitration for Sport do for Protecting Human Rights in Sports?

Sports governing bodies establish their sporting rules and regulations. Nevertheless, they confront a complex question concerning whether a female athlete who inherently possesses an advantageous quantity of testosterone may participate in female athletic competitions. In Caster Semenya and Athletics South Africa (ASA) v. IAAF, the Court of Arbitration for Sport (CAS) held that she could not participate in female sports events because “the elevated testosterone levels that such athletes possess can create an insuperable advantage over other female athletes who do not have a 46 XY DSD condition”. Consequently, the CAS ruled that she would no longer be eligible to compete in professional female competitions. In this scenario, the primary focus of this article is to examine how the CAS should address human rights-related issues, even though it is not a human rights court like the European Court of Human Rights (ECtHR) but rather an arbitral tribunal. To achieve this purpose, this article will address the following questions: (1) How can athletes claim a violation of their human rights before the CAS?; and (2) What steps should the CAS take to safeguard human rights in sports? Through this research, it may serve to identify the CAS’s role in human rights protection in sports.

DMRT1 is a testis-determining gene in rabbits and is also essential for female fertility

DMRT1 is the testis-determining factor in several species of vertebrates, but its involvement in mammalian testes differentiation, where SRY is the testis-determining gene, remains ambiguous. So far, DMRT1 loss-of-function has been described in two mammalian species and induces different phenotypes: Disorders of Sex Development (46, XY DSD) in men and male infertility in mice. We thus abolished DMRT1 expression by CRISPR/Cas9 in a third species of mammal, the rabbit. First, we observed that gonads from XY DMRT1−/− rabbit fetuses differentiated like ovaries, highlighting that DMRT1 is involved in testis determination. In addition to SRY, DMRT1 is required in the supporting cells to increase the expression of the SOX9 gene, which heads the testicular genetic cascade. Second, we highlighted another function of DMRT1 in the germline since XX and XY DMRT1−/− ovaries did not undergo meiosis and folliculogenesis. XX DMRT1−/− adult females were sterile, showing that DMRT1 is also crucial for female fertility. To conclude, these phenotypes indicate an evolutionary continuum between non-mammalian vertebrates such as birds and non-rodent mammals. Furthermore, our data support the potential involvement of DMRT1 mutations in different human pathologies, such as 46, XY DSD as well as male and female infertility.

DMRT1 is a testis-determining gene in rabbits and is also essential for female fertility.

DMRT1 is the testis-determining factor in several species of vertebrates, but its involvement in mammalian testes differentiation, where SRY is the testis-determining gene, remains ambiguous. So far, DMRT1 loss-of-function has been described in two mammalian species and induces different phenotypes: Disorders of Sex Development (46, XY DSD) in men and male infertility in mice. We thus abolished DMRT1 expression by CRISPR/Cas9 in a third species of mammal, the rabbit. First, we observed that gonads from XY DMRT1-/- rabbit fetuses differentiated like ovaries, highlighting that DMRT1 is involved in testis determination. In addition to SRY, DMRT1 is required in the supporting cells to increase the expression of the SOX9 gene, which heads the testicular genetic cascade. Second, we highlighted another function of DMRT1 in the germline since XX and XY DMRT1-/- ovaries did not undergo meiosis and folliculogenesis. XX DMRT1-/- adult females were sterile, showing that DMRT1 is also crucial for female fertility. To conclude, these phenotypes indicate an evolutionary continuum between non-mammalian vertebrates such as birds and non-rodent mammals. Furthermore, our data support the potential involvement of DMRT1 mutations in different human pathologies, such as 46, XY DSD as well as male and female infertility.

Study of 5 Alpha Reductase Enzyme Gene Mutations in a Group of Patients with 46XY Disorders of Sex Development

Background Disorders of sex development (DSD) are a wide range of conditions with diverse features and pathophysiology that most often present in the newborn or the adolescent periods. Affected patients usually present with atypical genitalia like hypospadias, isolated micropenis and undescended testis. These clinical situations can often be difficult to manage, particularly in those cases where the sex rearing is uncertain. Aim of the Work Studying 5alpha reductase enzyme gene mutations (SRD5A2) in patients with 46XY DSD to detect its molecular characteristics. Patients and Methods This cross-sectional study was performed on 25 male patients with clinical, laboratory and genetic molecular analysis of SRD5A2 gene mutation fitting the diagnosis of 46XY DSD. To assess the degree of virilization external masculinization score (EMS) was used where EMS less than 7 is considered ambiguous. All parameters were evaluated at the pediatrics endocrinology clinic and genetics department, Ain Shams University from December 2019 to December 2020. Results Only 12 patients showed laboratory and molecular results compatible with the diagnosis of SRD5A2 gene mutation, The mean age of the patients was 3.64 ± 4.75 years. Results showed EMS of 4.3 denoting the high degree of genital ambiguity in our cases. Scrotum was bifid in 5 patients (41.6%), underdeveloped in 5 patients (41.6%) and fused in 2 patients (16.8%). Cryptorchidism was found in 4 patients only (33.3%). Four patients (33.3%) had normal urethral opening while hypospadias was present in 8 patients being perineal in 1 patient (8.3%), perineoscrotal in 5 patients (41.6%) and scrotal in 2 patients (16.6%). Micropenis was present in 7 patients (58.3%), four patients had 2 openings (33.3%) compared to a single opening in 8 patients (66.7%). Regarding type of SRD5A2 gene mutations 56.2% of mutations were Insertion deletion, 25% were Insertion, 12.5 % were Missense, 6.25% were Deletion. Conclusion This study demonstrated ten novel mutations of SRD5A2 gene were identified in association with 5alpha reductase enzyme deficiency. These mutations were reported among 12 patients with 46 XY DSD from total of 25 patients were fit for this study. No distinct relationships were observed between genotypic and phenotypic characteristics in the participants.

The genetic spectrum of a Chinese series of patients with 46, XY disorders of the sex development.

The etiology of 46, XY disorders of sex development (46, XY DSD) is complex, and studies have shown that different series of patients with 46, XY DSD has different genetic spectrum. In this study, we aimed to investigate the underlying genetic etiology in a Chinese series of patients with 46, XY DSD by whole exome sequencing (WES). Seventy patients with 46, XY DSD were enrolled from the Peking Union Medical College Hospital (Beijing, China). The detailed clinical characteristics were evaluated, and peripheral blood was collected for WES to find the patients' rare variants (RVs) of genes related to 46, XY DSD. The clinical significance of the RVs was annotated according to American College of Medical Genetics and Genomics (ACMG) guidelines. A total of 57 RVs from nine genes were identified in 56 patients with 46, XY DSD, which include 21 novel RVs and 36 recurrent RVs. Based on the American ACMG guidelines, 43 variants were classified as pathogenic(P) or likely pathogenic (LP) variants and 14 variants were defined as variants of uncertain significance (VUS). P or LP variants were identified in 64.3% (45/70) patients of the series. Thirty-nine, 14, and 4 RVs were involved in the process of androgen synthesis and action, testicular determination and developmental process, and syndromic 46, XY DSD, respectively. The top three genes most frequently affected to cause 46, XY DSD were AR, SRD5A2, and NR5A1. Seven patients were found harboring RVs of the 46, XY DSD pathogenic genes identified in recent years, namely DHX37 in four patients, MYRF in two patients, and PPP2R3C in one patient. We identified 21 novel RVs of nine genes, which extended the genetic spectrum of 46, XY DSD pathogenic variants. Our study showed that 60% of the patients were caused by AR, SRD5A2 or NR5A1 P/LP variants. Therefore, polymerase chain reaction (PCR) amplification and Sanger sequencing of these three genes could be performed first to identify the pathogeny of the patients. For those patients whose pathogenic variants had not been found, whole-exome sequencing could be helpful in determining the etiology.

Misdiagnosis of 46, XY DSD in a childhood Bone Marrow Transplantation survivor

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

A novel p.Leu197Pro homozygous variant in HSD3B2 as a cause of 46,XY DSD with hyperpigmentation in an infant

We report a novel missense variant of the HSD3B2 gene in a 46,XY child born to third degree consanguineous parents presenting with undervirilization and progressive hyperpigmentation. The steroid profile showed elevated concentrations of 17-hydroxyprogesterone, but normal androstenedione and testosterone. The adrenocorticotropic hormone was elevated. The direct DNA sequencing of the child revealed a new homozygous missense variant in the HSD3B2 gene, resulting in the amino acid substitution of proline for leucine at codon 197. We have described a hitherto novel HSD3B2 gene variant in an undervirilized male infant causing 3β-hydroxysteroid dehydrogenase 2 deficiency.

Undetectable anti-Mullerian hormone and inhibin B do not preclude the presence of germ cell tumours in 45,X/46,XY or 46,XY gonadal dysgenesis.

Individuals with 45,X/46,XYor 46,XYgonadal dysgenesis are at increased risk of germ cell malignancies. Therefore, prophylactic bilateral gonadectomy is advised in girls and considered in boys with atypical genitalia for undescended, macroscopically abnormal gonads. However, severely dysgenetic gonads may not contain germ cells rendering gonadectomy unnecessary. Therefore, we investigate if undetectable preoperative serum anti-Müllerian hormone(AMH) and inhibin B can predict the absence of germ cells, (pre)malignant or otherwise. Individuals who had undergone bilateral gonadal biopsy and/or gonadectomy because of suspected gonadal dysgenesis in 1999-2019 were included in this retrospective study if preoperative AMH and/or inhibin B were available. Histological material was reviewed by an experienced pathologist. Haematoxylin and eosin and immunohistochemical stainings for SOX9, OCT4, TSPY and SCF (KITL) were used. Thirteen males and 16 females were included, 20 with 46,XYand 9 with 45,X/46,XY DSD. Threefemales had dysgerminoma alongside gonadoblastoma; twogonadoblastoma, one germ cell neoplasia in situ (GCNIS) and three males had pre-GCNIS and/or pre-gonadoblastoma. Gonadoblastoma and/or dysgerminoma were present in 3/11 individuals with undetectable AMH and inhibin B, one of whom also had non-(pre)malignant germ cells. Of the other 18, in whom AMH and/or inhibin B were detectable, only one had no germ cells. Undetectable serum AMH and inhibin B cannot reliably predict the absence of germ cells and germ cell tumours in individuals with 45,X/46,XYor 46,XYgonadal dysgenesis. This information should help in counselling about prophylactic gonadectomy, taking into account both the germ cell cancer risk and potential for gonadal function.

Modulatory activity of testosterone on growth pattern and IGF-1 levels in vanishing testis syndrome: a case report during 15 years of follow-up

BackgroundThe vanishing testis syndrome (VTS), is a 46, XY disorder of sex development (46, XY DSD) and is characterized by the absence of testis in a 46, XY subject with male genitalia, gonadal dysgenesis and consequent hypergonadotropic hypogonadism.Case presentationA young man affected by VTS has been followed up for more than 15-year in our center. The patient received different testosterone formulations, which modulated his IGF-1 levels and height velocity, depending on different stimulatory effects, mimicking pubertal spurt until achieving a final height in line with his genetic target.Exogenous testosterone, activating GH/IGF-1 system, can directly influence growth pattern. With this particular case report we demonstrate that an accurate monitoring of patients with VTS, as well as a perfect reproduction of testosterone secretion during pubertal spurt, can guarantee a normal growth and development and, consequently, a high level of quality of life in adulthood.ConclusionTestosterone levels act an important role during pubertal spurt in modulating the GH/IGF-1 axis, besides its well-known impact in sexual development.Very little amount of exogenous testosterone can stimulate IGF-1 secretion and provide to growth velocity the drive that characterizes the initial phases of the growth spurt.

Comprehensive molecular analysis identifies eight novel variants in XY females with disorders of sex development.

Disorders of sex development (DSD) are a group of clinical conditions with variable presentation and genetic background. Females with or without development of secondary sexual characters and presenting with primary amenorrhea (PA) and a 46,XY karyotype are one of the classified groups in DSD. In this study, we aimed to determine the genetic mutations in 25 females with PA and a 46,XY karyotype to show correlations with their phenotypes. Routine Sanger sequencing with candidate genes like SRY, AR, SRD5A2, and SF1, which are mainly responsible for 46,XY DSD in adolescent females, was performed. In a cohort of 25 patients of PA with 46,XY DSD, where routine Sanger sequencing failed to detect the mutations, next-generation sequencing of a targeted gene panel with 81 genes was used for the molecular diagnosis. The targeted sequencing identified a total of 21 mutations including 8 novel variants in 20 out of 25 patients with DSD. The most frequently identified mutations in our series were in AR (36%), followed by SRD5A2 (20%), SF1 (12%), DHX37 (4%), HSD17B3 (4%), and DMRT2 (4%). We could not find any mutation in the DSD-related genes in five (20%) patients due to complex molecular mechanisms in 46,XY DSD, highlighting the possibility of new DSD genes which are yet to be discovered in these disorders. In conclusion, genetic testing, including cytogenetics and molecular genetics, is important for the diagnosis and management of 46,XY DSD cases.