Intellectual Developmental Disorder, Autosomal Recessive 4, also known as autosomal recessive intellectual developmental disorder 4, is related to chronic bilirubin encephalopathy. An important gene associated with Intellectual Developmental Disorder, Autosomal Recessive 4 is MRT4 (Mental Retardation, Non-Syndromic, Autosomal Recessive, 4). Related phenotypes are intellectual disability and global developmental delay