Genetic testing in pediatric endocrine pathology

Abstract

In genetic endocrine diseases, genetic testing is necessary for a precise diagnosis, which will provide a better knowledge of the evolution and prognosis and also indicate the adequate therapy, targeting the precise etiopathogenesis of the disease. Genetic testing in endocrinology is often based on classical cytogenetic techniques, molecular cytogenetic analysis or molecular biology techniques. Genetic testing in disorders of sex development includes the karyotype and SRY gene analysis and depending on the presence of associated clinical signs and on the observations at paraclinical examination, these tests will be followed by chromosomal array techniques and NGS sequencing. In short stature, the decision to perform a genetic test is taken depending on clinical, paraclinical and imaging signs. In case of a short stature associated with a low weight/length for gestational age, genetic testing is proposed to evaluate a Russell-Silver syndrome or if the short stature is associated with other clinical signs (e.g. intellectual disability), chromosomal analysis by microarray is proposed. If the short stature is disproportionate, it is indicated to perform a next generation sequencing (NGS) of a panel of genes involved in skeletal dysplasia. If an endocrine cause for short stature is observed at the hormonal evaluation, it is indicated to test a panel of genes involved in these pathways. In genetic obesity, depending on clinical signs associated to obesity, it will be a more targeted genetic testing. If obesity is associated with intellectual disability or other nonspecific neurological changes, a chromosomal analysis by microarray will be indicated. If monogenic obesity is suspected, NGS testing will be indicated (as genes panel or whole exome or genome analysis). Genetic testing in endocrine diseases brings an etiological diagnosis, but a favorable cost-benefit ratio derives from an adequate indication of these tests, generally proposed in expert centers for rare endocrine diseases.

Keywords: disorders of sex development; genetic testing; obesity; short stature.