Clinical, Hormonal, and Genetic Spectrum of 46 XY Disorders of Sexual Development (DSD) Patients

OBJECTIVES

To evaluate the clinical, hormonal and genetic characteristics of 46XY disorders of sexual development (DSD) patients from South India.

METHODS

46XY DSD patients with a provisional diagnosis of 17β-hydroxysteroid dehydrogenase 3 (17BHSD3) deficiency, 5 alpha-reductase type 2 deficiency (5ARD2) or partial androgen insensitivity syndrome (PAIS) based on clinical and hormonal analysis were included in this study. All the patients underwent detailed clinical and hormonal evaluations. Targeted next-generation sequencing for all three genes (AR, HSD17B3, and SRD5A2) in parallel was carried out for all the included patients and their parents.

RESULTS

Based upon the clinical and hormonal analysis, among the 37 children with 46XY DSD in the present study, 21 children were diagnosed with 5ARD2, 10 with PAIS, and six with 17BHSD3 deficiency. However, genetic analysis revealed pathogenic mutations in nine patients - six in the AR gene, two in the SRD5A2 gene, and one in the HSD17B3 gene. The concordance rate between provisional hormonal and genetic diagnosis was only 22.2%. Two out of six subjects with AR gene variants were positive for somatic mosaicism.

CONCLUSIONS

In the present study, a positive genetic diagnosis was detected in nine patients (24%), including five novel variants. In this study, mutations in the AR gene was the most reported. The authors did not find the testosterone: dihydrotestosterone (T: DHT) ratio to be an accurate hormonal diagnostic tool.

Rupture and hemorrhage of a seminoma mixed with yolk sac tumors in 46XY partial gonadal dysgenesis: a case report and literature review

Background

46XY partial gonadal dysgenesis (PGD) is a rare subtype of disorder of sex development (DSD). 46YY PGD is a congenital disease with atypical chromosomal, gonadal, or anatomical sex development. The patient in this case report had male and female genitalia simultaneously. We created a flowchart of the differential diagnosis for clinicians.

Case presentation

A 41-year-old male was admitted to the hospital complaining of lower quadrant abdominal pain for 1 day. Physical examination revealed that his penis size was normal, but a urethral orifice was located in the perineum area between the scrotum and anus. One small testicle was in the left scrotum, but no testicle was present on the right. The patient’s abdomen was bulging, and he had lower abdominal pain. According to the emergency CT scan, a lesion (74*65 mm) was found in the right pelvis between the bladder and rectum. The lesion showed an unclear boundary and hematocele appearance. The lesion was removed by emergency surgery, and the pathology report indicated a mixed germ cell tumor with a seminoma and yolk sac tumors.

Conclusion

This article is a case report of germ cell tumors in 46XY PGD patients. The literature review summarizes the clinical diagnosis, and a flowchart is provided for physicians in future practice. The importance of this report is that it will help acquaint physicians with this rare disease and make the right initial clinical decision quickly through the use of this flowchart. However, the variants of special subtypes of 46XY DSD are myriad, and all the diagnoses could not be covered in one flowchart.

Novel mutations of the LHCGR gene in two families with 46,XY DSD causing Leydig cell hypoplasia I

PURPOSE

Leydig cell hypoplasia is a rare autosomal recessive 46,XY disorder of sexual development (DSD). It is caused by homozygous or compound heterozygous inactivating mutations in the human luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) gene. In Leydig cell hypoplasia type I, patients are characterized by predominantly female external genitalia, which usually go unrecognized until the age of puberty.

METHODS

This study reports three patients descending from two unrelated families. We performed clinical, hormonal, histopathological, molecular, and bioinformatics studies for the studied cases.

RESULTS

All investigations suggested 46,XY DSD and Leydig cell hypoplasia. Molecular analysis showed two novel homozygous inactivating mutations (p.Glu148Ter and p.Leu104Pro) within the extracellular domain of the LHCGR gene.

CONCLUSION

Although the mutations of the LHCGR gene are distributed heterogeneously, without hotspot or recurrent mutations, about one fifth of the reported mutations worldwide have been detected in Arab patients. This is probably due to the high consanguinity rate in these populations, which increases the percentage of autosomal recessive disorders and the homozygous LHCGR gene mutations.

Integrative and Analytical Review of the 5-Alpha-Reductase Type 2 Deficiency Worldwide

Introduction

The conversion of testosterone into dihydrotestosterone is catalyzed by the 5α-reductase type 2 enzyme which plays a crucial role in the external genitalia virilization. It is encoded by the SRD5A2 gene. Allelic variants in this gene cause a 46,XY DSD with no genotype-phenotype relationship. It was firstly reported in the early 70s from isolated clusters. Since then, several cases have been reported. Putting together, it will expand the knowledge on the molecular bases of androgen milieu.

Methods

We searched for SRD5A2 allelic variants (AV) in the literature (PubMed, Embase, MEDLINE) and websites (ensembl, HGMD, ClinVar). Only cases with AV in both alleles, either in homozygous or compound heterozygous were included. The included cases were analyzed according to ethnicity, exon, domain, aminoacid (aa) conservation, age at diagnosis, sex assignment, gender reassignment, external genitalia virilization and functional studies. External genitalia virilization was scored using Sinnecker scale. Conservation analysis was carried out using the CONSURF platform. For categorical variables, we used X2 test and Cramer's V. Continuous variables were analyzed by t test or ANOVA. Concordance was estimated by Kappa.

Results

We identified 434 cases of 5ARD2 deficiencies from 44 countries. Most came from Turkey (23%), China (17%), Italy (9%), and Brazil (7%). Sixty-nine percent were assigned as female. There were 70% of homozygous allelic variants and 30% compound heterozygous. Most were missense variants (76%). However, small indels (11%), splicing (5%) and large deletions (4%) were all reported. They were distributed along with all exons with exon 1 (33%) and exon 4 (25%) predominance. Allelic variants in the exon 4 (NADPH-binding domain) resulted in lower virilization (p<0.0001). The codons 55, 65, 196, 235 and 246 are hotspots making up 25% of all allelic variants. Most of them (76%) were located at conserved aa. However, allelic variants at non-conserved aa were more frequently indels (28% vs 6%; p<0.01). The overall rate of gender change from female to male ranged from 16% to 70%. The lowest rate of gender change from female to male occurred in Turkey and the highest in Brazil. External genitalia virilization was similar between those who changed and those who kept their assigned gender. The gender change rate was significantly different across the countries (V=0.44; p<0.001) even with similar virilization scores.

Conclusion

5ARD2 deficiency has a worldwide distribution. Allelic variants at the NADPH-ligand region cause lower virilization. Genitalia virilization influenced sex assignment but not gender change which was influenced by cultural aspects across the countries. Molecular diagnosis influenced on sex assignment, favoring male sex assignment in newborns with 5α-reductase type 2 deficiency.

Steroid 17-hydroxylase and 17,20-lyase deficiencies, genetic and pharmacologic

Steroid 17-hydroxylase 17,20-lyase (cytochrome P450c17, P450 17A1, CYP17A1) catalyzes two major reactions: steroid 17-hydroxylation followed by the 17,20-lyase reactions. The most severe mutations in the cognate CYP17A1 gene abrogate all activities and cause combined 17-hydroxylase/17,20-lyase deficiency (17OHD), a biochemical phenotype that is replicated by treatment with the potent CYP17A1 inhibitor abiraterone acetate. The adrenals of patients with 17OHD synthesize 11-deoxycorticosterone (DOC) and corticosterone but no 19-carbon steroids, similar to the rodent adrenal, and DOC causes hypertension and hypokalemia. Loss of 17,20-lyase activity precludes sex steroid synthesis and leads to sexual infantilism. Rare missense CYP17A1 mutations minimally disrupt 17-hydroxylase activity but cause isolated 17,20-lyase deficiency (ILD), Mutations in the POR gene encoding the required cofactor protein cytochrome P450-oxidoreductase causes a spectrum of disease from ILD to 17OHD combined with 21-hydroxylase and aromatase deficiencies, sometimes including skeletal malformations. Mutations in the CYB5A gene encoding a second cofactor protein cytochrome b₅ also selectively disrupt 17,20-lyase activity and cause the purest form of ILD. The clinical manifestations of these conditions are best understood in the context of the biochemistry of CYP17A1.