A syndrome that involves significant neurodevelopmental features that do not fulfill the diagnostic requirements of any of the specific Transtornos do neurodesenvolvimento that is judged to be a direct pathophysiological consequence of a health condition not classified under mental and behavioural transtornos (e.g., autistic-like features in Rett syndrome; aggression and self-mutilation in Lesch-Nyhan syndrome, abnormalities in language development in Williams syndrome), based on evidence from the history, physical examination, or laboratory findings. This category should be used in addition to the diagnosis for the presumed underlying transtorno or disease when the neurodevelopmental problems are sufficiently grave to warrant specific clinical attention.