Brain biomarkers of inborn errors of metabolism using fNIRS

Inborn errors of metabolism (IEM) are associated with mild to severe brain dysfunction. Studying biomarkers of the brain in this cohort is challenging not only because of the disorder’s complication but also due to the small and geographically dispersed population. On the other hand, most of these individuals are infants or children. We use functional near-infrared spectroscopy (fNIRS) to study brain abnormalities in patients with various IEMs at Children’s National Hospital and St Jude Children’s Research Hospital. As each disorder might affect different cortical regions, we employ a full-head imaging cap to obtain brain functional signals. Based on our findings, patients with the rare conditions we study demonstrate significant differences in brain activation compared to the control population. However, with large samples, we will compare one category of IEM to another to develop maps of cognitive function for each condition. Our current focus is on patients with Urea Cycle Disorders (UCD), Maple Syrup Urine Disorder (MSUD), and Glut1 Deficiency, all with different enzymatic deficiencies and brain regions of vulnerability but with some shared effects on executive function.