Development of Laboratory Investigations in Disorders of Sex Development

Abstract

Scientific knowledge to understand the biological basis of sex development was prompted by the observation of variants different from the 2 most frequent body types, and this became one of the fields first studied by modern pediatric endocrinology. The clinical observation was supported by professionals working in different areas of laboratory sciences which led to the description of adrenal and gonadal steroidogenesis, the enzymes involved, and the different deficiencies. Steroid hormone measurements evolved from colorimetry to radioimmunoassay (RIA) and automated immunoassays, although gas and liquid chromatography coupled to mass spectrometry are now the gold standard techniques for steroid measurements. Peptide hormones and growth factors were purified, and their measurement evolved from RIA to automated immunoassays. Hormone action mechanisms were described, and their specific receptors were characterized and assayed in experimental materials and in patient tissues and cell cultures. The discovery of the genetic basis for variant sex developments began with the description of the sex chromosomes. Molecular technology allowed cloning of genes coding for the different proteins involved in sex determination and development. Experimental animal models aided in verifying the roles of proteins and also suggested new genes to be investigated. New candidate genes continue to be described based on experimental models and on next-generation sequencing of patient DNAs.

Androgens by immunoassay and mass spectrometry in children with 46,XY disorder of sex development

“…The determination of steroid hormone concentration, which is part of the initial approach in the diagnosis of Disorders of Sex Development (DSD), is one of the challenges in pediatric endocrinology (1)(2)(3). Based on the principle of antigen-antibody complex formation, immunoassays (IA) are widely used in clinical practice due to its low cost, easy technical application and reproducibility (2)(3)(4). However, IA for the measurement of analytes such as the steroids that presents low antigenic activity do not offer proper specificity (1,3).…”

“…Based on the principle of antigen-antibody complex formation, immunoassays (IA) are widely used in clinical practice due to its low cost, easy technical application and reproducibility (2)(3)(4). However, IA for the measurement of analytes such as the steroids that presents low antigenic activity do not offer proper specificity (1,3).…”

“…The use of liquid or gas chromatography coupled to mass spectrometry (MS) is frequently used for steroid analyses (1,3,4). These techniques are more specific and more accurate than IA (6), however they are still high cost methods and are not available as routine tests in most laboratories (3,4).…”

“…More recently, liquid chromatography coupled with mass spectrometry in tandem (LC-MS/MS) has replaced conventional methods of steroid hormone analysis, enabling the use of small volume samples, improving specificity and reducing the time of analyses (3,7,8).…”

“…The use of LC-MS/MS in research laboratories has expanded (3,4), because it has proved useful in improving the accuracy of steroid measurements, especially in low concentration samples, as observed in children with DSD (2). One of the most important challenge is the measurement of testosterone concentration (9,10), especially in the investigation of 46,XY DSD cases.…”