[Inborn errors of metabolism are not hopeless; early identification of treatable conditions in children with intellectual disability].

Intellectual disability is a devastating condition affecting 2-3% of the global population; comorbidity is common. In addition to its lifelong impact on affected individuals, families and society as a whole, intellectual disability is associated with the highest healthcare costs of any disease. Inborn errors of metabolism constitute a group of rare genetic disorders that commonly manifest as an intellectual disability. For patients with these disorders, an increasing number of treatments are becoming available aimed at the pathophysiological mechanisms. A review of the literature identified 91 treatable inherited metabolic disorders; this was the basis for the development of a step-by-step diagnostic protocol and an app, Treatable-ID. A 2.5-year study in a tertiary setting treatable inborn errors of metabolism were identified as cause of intellectual disability in more than 5% of the children studied. It also showed that implementation of the diagnostic protocol reduced unnecessary costs and diagnostic delay. These results should motivate clinicians to aim diagnostic assessment of an individual with intellectual disability at treatable inborn errors of metabolism. Such an approach prevents brain damage, improves development and health and gives patients hope.