Uniprot Description A life-threatening, autosomal recessive neurometabolic disorder characterized by severe neurological impairment. Classic ISOD manifests in the first few hours to days of life and is characterized by intractable seizures, feeding difficulties, rapidly progressive encephalopathy, microcephaly, and profound intellectual disability. Children usually die during the first few months of life. Mild ISOD manifests in infancy or early childhood and is characterized by ectopia lentis that is variably present, developmental delay and regression, movement disorder characterized by dystonia and choreoathetosis, ataxia, and rarely acute hemiplegia due to metabolic stroke.