Neuroimaging in inborn errors of metabolism

Abstract

Inborn errors of metabolism (IEM) are a group of more than 8000 monogenic inherited diseases, and according to the online database of IEM (“IEMbase”), around 1900 of them are recognized so far. Most often they are caused by pathogenic variants of nuclear genes, and a smaller proportion of them are caused by pathogenic variants of genes in mitochondrial DNA. The result of these mutations is either the accumulation of toxic or the lack of essential metabolic products. These disorders cause more or less specific clinical symptoms, as a result of the involvement of various organs or tissues, and most of them will also affect the central nervous system. Clinical symptoms can occur at any age, from intrauterine to late adulthood. The possibility of treatment and mitigation of consequences significantly depends on timely diagnosis. Neuroimaging with specific patterns of CNS involvement can narrow the differential diagnosis and direct further management of the patient. However, neuroradiological findings vary from normal findings to extensive changes, depending on a number of factors (type and duration of the disease, the amount of accumulated toxic metabolites, brain maturity, and the stage of the disease in which MRI is performed). Given the number of these disorders, it is not possible to include them all in thid short review, so the aim of this paper is to provide several examples with a typical neuroradiological presentation of IEMs.