Investigação etiológica nas situações de deficiência intelectual ou atraso global do desenvolvimento

Objectives: We aimed to analyze studies about the etiological diagnosis of intellectual disability or global developmental delay, organizing the process of causal investigation in a flowchart suitable to the clinical practice. Methods: A non-systematic literature review was conducted on PubMed and SciELO databases, without data or language filters. The relevant articles were selected, critically analyzed and their results synthesized. Results: Environmental causes of disability should be considered in the clinical history, with identification of pre, peri and postnatal risk factors. Family history and physical, dysmorphological and neurological findings may suggest the etiology and guide the investigation. To investigate genetic causes, chromosomal microarray analysis is indicated as a first-line test, along with the searching for inborn errors of metabolism and X-fragile syndrome. Neuroimaging is important in selected patients, as well as the investigation of other X-linked genes. There is an emerging discussion about the role of complete exome sequencing in this investigation. Conclusions: The frequency of etiological definition has increased with the incorporation of new genetic technologies to the investigation of intellectual disability. In addition to etiological investigation, the clinical approach should address the multiple demands and allow the development of an individualized therapeutic plan.