developmental disability (MONDO_0005287, a Monarch Disease Ontology term) can be described as follows. Disorders in which there is a delay in development based on that expected for a given age level or stage of development. These impairments or disabilities originate before age 18, may be expected to continue indefinitely, and constitute a substantial impairment. Biological and nonbiological factors are involved in these disorders. (From American Psychiatric Glossary, 6th ed).