Overview of genetics of disorders of sexual development

Dermatologic care of patients with differences of sex development

Background

Differences of sex development (DSD or disorders of sex development) are uncommon congenital conditions, characterized by atypical development of chromosomal, gonadal, or anatomic sex.

Objective

Dermatologic care is an important component of the multidisciplinary care needed for individuals with DSD. This article discusses the most common primary dermatologic manifestations of DSD in addition to the cutaneous manifestations of hormonal and surgical therapies in individuals with DSD.

Data sources

Published articles including case series and case reports on PubMed.

Study selections

Selection was conducted by examining existing literature with a team of multidisciplinary specialists.

Methods

Narrative review.

Limitations

This article was not conducted as a systematic review.

Results

In Klinefelter syndrome, refractory leg ulcers and incontinentia pigmenti have been described. Turner syndrome is associated with lymphatic malformations, halo nevi, dermatitis, and psoriasis. Virilization can be seen in some forms of congenital adrenal hyperplasia, where acne and hirsutism are common.

Conclusion

Dermatologists should consider teratogenic risk for treatments of skin conditions in DSD depending on pregnancy potential. Testosterone replacement, commonly used for Klinefelter syndrome, androgen insensitivity syndrome, 5-alpha reductase deficiency, gonadal dysgenesis, or ovotesticular DSD, may cause acne.

A Homozygous Missense Variant in Hedgehog Acyltransferase (HHAT) Gene Associated with 46,XY Gonadal Dysgenesis

INTRODUCTION

Disorders of gonadal development represent a clinically and genetically heterogeneous group of DSD, and the etiology in many cases remains unknown, indicating that our knowledge of factors controlling sex determination is still limited.

METHODS

We describe a 46,XY DSD patient from Egypt. The patient was reared as female, born to consanguineous parents, and was referred to us at the age of 5 years because of ambiguous genitalia. On examination, the girl was microcephalic (head circumference -3 SD), but her height and weight were normal for her age and sex.

RESULTS

Exome sequencing identified a homozygous variant in the hedgehog acyltransferase (HHAT) gene, which encodes an enzyme that is required for multimerization and signaling potency of the hedgehog secreted proteins. The variant is a novel homozygous missense change c.1329C>A (p.N443K), located within transmembrane domain 9, which segregated with the phenotype in the family.

DISCUSSION/CONCLUSION

Our results expand the phenotypic spectrum associated with HHAT variants to include 46,XY gonadal dysgenesis and reinforce the role of exome sequencing in unraveling new genes that play a pivotal role in sexual development.

Whole-Exome Sequencing Identified Rare Genetic Variants Associated with Undervirilized Genitalia in Taiwanese Pediatric Patients

Disorders/differences of sex development (DSDs) are a group of rare and phenotypically variable diseases. The underlying genetic causes of most cases of 46XY DSDs remains unknown. Despite the advent of genetic testing, current investigations of the causes of DSDs allow genetic-mechanism identification in about 20-35% of cases. This study aimed primarily to establish a rapid and high-throughput genetic test for undervirilized males with and without additional dysmorphic features. Routine chromosomal and endocrinological investigations were performed as part of DSD evaluation. We applied whole-exome sequencing (WES) complemented with multiplex ligation-dependent probe amplification to seek explainable genetic causes. Integrated computing programs were used to call and predict the functions of genetic variants. We recruited 20 patients and identified the genetic etiologies for 14 (70%) patients. A total of seven of the patients who presented isolated DSD phenotypes were found to have causative variants in the AR, MAP3K1, and FLNA genes. Moreover, the other seven patients presented additional phenotypes beyond undervirilized genitalia. Among them, two patients were compatible with CHARGE syndrome, one with Robinow syndrome, and another three with hypogonadotropic hypogonadism. One patient, who carried a heterozygous FLNA mutation, also harbored a heterozygous PTPN11 mutation and thus presented some phenotypes of Noonan syndrome. We identified several genetic variants (12 nonsense mutations and one microdeletion) that account for syndromic and nonsyndromic DSDs in the Taiwanese population. The identification of these causative genes extended our current understanding of sex development and related congenital disorders.

True hermaphroditism with dysgerminoma: A case report

INTRODUCTION

True hermaphroditism is a rare and usually sporadic disorder. It is defined by the presence of both ovarian and testicular tissues together as ovotestis.

PATIENT CONCERNS

In this study, we reported a rare true hermaphroditism case with dysgerminoma. A 49-year-old woman developed masses in both inguinal regions for 30 years. Recently 3 months, the patient found that the size of mass in her left inguinal region was significantly increased.

DIAGNOSIS

After surgical resection, the results of immunohistochemical examination in left mass revealed a dysgerminoma with positive expression of placental alkaline phosphatase and octamer-binding transcription factor 3/4, and right mass was a cryptorchidism. Chromosomal analysis revealed the karyotype 46, XY. Combined immunohistochemical and karyotype analysis, a diagnosis of true hermaphroditism with dysgerminoma was made.

INTERVENTIONS

Radiotherapy combined with chemotherapy after tumor resection was used to improve her prognosis. Hormone replacement therapy with conjugated estrogen and medroxyprogesterone acetate were used to maintain her female characteristics.

OUTCOMES

The patient underwent hormonal replacement and has been well for 6 months.

CONCLUSION

The positive expression of placental alkaline phosphatase and octamer-binding transcription factor 3/4 could be 2 diagnosis markers of dysgerminoma. Surgery combined with radiotherapy and chemotherapy could improve the prognosis of dysgerminoma. Moreover, hormone replacement therapy with conjugated estrogen and medroxyprogesterone acetate was very helpful to maintain the female characteristic of patients with true hermaphroditism.

High Molecular Diagnosis Rate in Undermasculinized Males with Differences in Sex Development Using a Stepwise Approach

Differences of sex development (DSDs) are a constellation of conditions that result in genital ambiguity or complete sex reversal. Although determining the underlying genetic variants can affect clinical management, fewer than half of undermasculinized males ever receive molecular diagnoses. Next-generation sequencing (NGS) technology has improved diagnostic capabilities in several other diseases, and a few small studies suggest that it may improve molecular diagnostic capabilities in DSDs. However, the overall diagnostic rate that can be achieved with NGS for larger groups of patients with DSDs remains unknown. In this study, we aimed to implement a tiered approach to genetic testing in undermasculinized males seen in an interdisciplinary DSD clinic to increase the molecular diagnosis rate in this group. We determined the diagnosis rate in patients undergoing all clinically available testing. Patients underwent a stepwise approach to testing beginning with a karyotype and progressing through individual gene testing, microarray, panel testing, and then to whole-exome sequencing (WES) if no molecular cause was found. Deletion/duplication studies were also done if deletions were suspected. Sixty undermasculinized male participants were seen in an interdisciplinary DSD clinic from 2008 to 2016. Overall, 37/60 (62%) of patients with Y chromosomes and 46% of those who were 46XY received molecular diagnoses. Of the 46,XY patients who underwent all available genetic testing, 18/28 (64%) achieved molecular diagnoses. This study suggests that the addition of WES testing can result in a higher rate of molecular diagnoses compared to genetic panel testing.

Variations of sex development: The first German interdisciplinary consensus paper

INTRODUCTION

The term variations of sex development subsumes a large number of congenital conditions including chromosomal mosaics and variations of chromosomal, gonadal, and phenotypic sex. A situation of this nature may cause severe distress to both, parents and affected persons. One of the reasons for this is the binary form of gender classification in the society. In the past, because of a fear of possible stigmatization and an inability to cope with complex situations, it has been medical policy and practice for newborns to undergo early, mostly 'feminizing' elective surgery with the aim of achieving an outer genital appearance that is unambiguously male or female. Protests by advocacy groups for the most part as well as the results of outcome studies have shown that the development of affected persons may be very different to what has been expected and often does not result in the intended clear female or male gender identity as had been intended. It, therefore, seemed a matter of urgency to implement this new awareness as well as the ethical and personal human rights perspectives in the recommendations for the medical and psychosocial management of diverse sex development (DSD) in the future.

STUDY DESIGN

In 2012, an interdisciplinary group of German academics engaged in the field of DSD decided to work on a consensus paper for this topic. It involved the participation of all faculties and non-scientific groups dealing with DSD, in particular advocacy and service-user groups. In a structured consensus, process recommendations were developed based on scientific literature as well as personal experiences of clinicians and affected individuals.

RESULTS

Finally, 37 recommendations were agreed on. The strength of consensus is reflected in the degree of agreement as expressed in percentages.

CONCLUSION

The introduction of the consensus paper reflects on the emerging paradigm shift and the necessity for a more open view of gender within society. The paper is intended to aid the performance of appropriate diagnostics in DSD-affected newborns and especially to help parents and affected persons cope with the biological and social consequences of DSD. With regard to medical or surgical therapy, it gives information about the most recent treatment trends.

Contemporary Demographic, Treatment, and Geographic Distribution Patterns for Disorders of Sex Development

This study aimed to describe the demographic characteristics, hospital utilizations, patterns of inpatient surgical management, and the overall state/regional variation in surgery rate among patients with disorders of sex development (DSD). We analyzed the Nationwide Inpatient Sample from 2001 to 2012 for patients younger than 21 years. DSD-related diagnoses and procedures were identified via International Classification of Diseases, Ninth Revision (ICD-9) codes. We identified a total of 43,968 DSD-related admissions. Of these, 73.4% of the admissions were designated as female and 642 (1.9%) were inpatient surgical admissions. Among neonates, less than 1% underwent any type of genital surgery. Nonsurgical admissions were associated with longer length of stay and higher cost. There was no significant regional variation in the rate of DSD surgeries, but we observed higher concentrations of DSD surgeries in states associated with tertiary referral centers.