Child with Suspected Metabolic Disorder

Inborn errors of metabolism (IEMs) with neurological consequences encompass a wide range of inherited genetic disorders. These disorders can affect the brain, nervous system, and muscles along with other organ systems. The signs and symptoms are often non-specific but can also include more specific neurological symptoms such as seizures, ataxia, or other movement disorders. Many disorders present in the newborn period and are often identified through newborn screening (NBS) programs. Commonly available laboratory tests can suggest specific categories of metabolic disorders such as amino acid, organic acid, or acylcarnitine abnormalities. Enzymatic and/or molecular genetic testing are used to confirm specific diagnoses. Findings on brain magnetic resonance imaging (MRI) or computed tomography (CT) scans and other imaging studies, as well as biopsies can also be specific to various disorders. This chapter provides an approach to diagnosing these groups of inborn errors of metabolism, focusing on those disorders that can present with neurological symptoms. Key points (potential neurological signs/symptoms, other signs/symptoms, laboratory abnormalities, diagnostic tests, and management) are included. Such disorders are typically managed by biochemical genetic specialists but include many other specialists as well. Most importantly, the initial suspicion of an inborn error of metabolism and implementation of early management and treatment are critical to a successful outcome for these patients.