The role of next generation sequencing in understanding male and female sexual development: clinical implications

Applying Single-Cell Analysis to Gonadogenesis and DSDs (Disorders/Differences of Sex Development)

The gonads are unique among the body's organs in having a developmental choice: testis or ovary formation. Gonadal sex differentiation involves common progenitor cells that form either Sertoli and Leydig cells in the testis or granulosa and thecal cells in the ovary. Single-cell analysis is now shedding new light on how these cell lineages are specified and how they interact with the germline. Such studies are also providing new information on gonadal maturation, ageing and the somatic-germ cell niche. Furthermore, they have the potential to improve our understanding and diagnosis of Disorders/Differences of Sex Development (DSDs). DSDs occur when chromosomal, gonadal or anatomical sex are atypical. Despite major advances in recent years, most cases of DSD still cannot be explained at the molecular level. This presents a major pediatric concern. The emergence of single-cell genomics and transcriptomics now presents a novel avenue for DSD analysis, for both diagnosis and for understanding the molecular genetic etiology. Such -omics datasets have the potential to enhance our understanding of the cellular origins and pathogenesis of DSDs, as well as infertility and gonadal diseases such as cancer.

Individualized care for patients with intersex (disorders/differences of sex development): part I

The care of individuals with disorders/differences of sex development aims to enable affected individuals and their families to have the best quality of life, particularly those born with severe genital ambiguity. Two of the biggest concerns for parents and health professionals are: (1) making a gender assignment and (2) the decisions of whether or not surgery is indicated, and if so, when is best for the patient and parents. These decisions, which can be overwhelming to families, are almost always made in the face of uncertainties. Such decisions must involve the parents, include multidisciplinary contributions, have an underlying principle of full disclosure, and respect familial, philosophical, and cultural values. Assignment as male or female is made with the realization that gender identity cannot be predicted with certainty. Because of the variability among those with the same diagnosis and complexity of phenotype-genotype correlation, the use of algorithms is inappropriate. The goal of this article is to emphasize the need for individualized care to make the best possible decisions for each patient's unique situation.

The evaluation and management of the boy with DSD

Atypical genitalia in a boy may have a very wide and diverse aetiology and a definitive diagnosis is often challenging to reach. Detailed clinical evaluation integrated with extensive biochemical and genetic studies play an important role in this process. Such care should be undertaken in highly specialized centres that can also provide access to a multidisciplinary team for optimal long-term care.