[Behavioral phenotypes and cognitive characteristics in mental retardation].

The authors in a review article deal with characteristic cognitive and behavioral features appearing in mental retardations, which later are referred as behavioral phenotypes. Nyhan (1972) introduced the term "behavioral phenotype" to describe outwardly observable behavior so characteristic of children with genetic disorders that its presence suggests the underlying genetic condition. The behavioral phenotype is a characteristic pattern of motor, cognitive, linguistic and social abnormalities that is consistently associated with a biological/neurodevelopmental disorder. This does not mean that the behavior is present in all instances but that the probability of its occurrence is increased. In the future, more may be learned about brain mechanisms and gene-brain interactions by comparing those with behavioral involvement with others with the same syndrome but without the behavioral features.