Etiologic Evaluation and Investigation of Global Development Delay and Intellectual Disability

Developmental Delay (DD) and Intellectual Disability (ID), depending on the affected individual being under or above five years-old, result from environmental or genetic causes during the developmental period, that manifest as a subnormal functioning of intellectual abilities. In western countries there is a prevalence of about 3%, with a great impact in the individuals, their families, as well as in the society. Etiologic diagnosis remains unknown in about 65-80% of the cases. It is a clinically heterogeneous condition as it can be sporadic or familiar, encompassing an autosomal dominant, recessive or X-linked transmission. Etiologic investigation emphasizes the importance of the clinical and family history as well as the physical examination, with special care for dysmorphologic evaluation. The authors reviewed DD/ ID focusing not only on clinical diagnosis but mostly on genetic causes and etiologic investigation. The protocol presented is followed by the Medical Genetics Department of Coimbra’s Paediatrics Hospital, in accordance to the international consensus