Cognitive profiles of genetic syndromes with intellectual disability

The study of similarities and differences in the cognitive profiles of persons with genetic-based Intellectual Disability is relevant to increase our understanding about the complex way in which genetic aspects affect cognitive processes. Genetic syndromes have been mainly studied with reference to withinprofile variability. The aim of our study was to compare cognitive syndrome profiles in order to detect those cognitive variables that better characterize each syndrome. Wechsler Intelligence Scale for Children was administered in a sample composed of 156 persons with mild or moderate Intellectual Disability, 94 males and 62 females, divided into four groups according to their genetic syndrome (Down or Trisomy-21, Williams, Prader-Willi, Fragile-X) The groups were paired on chronological and mental ages and levels of maladaptive behaviors. Variance analysis across syndromes, followed by a discriminant analysis, were performed for all the variables. Results showed that the delay in cognitive functions is higher in attentionconcentration and visuo-spatial constructive skills than in verbal skills. The genetic syndromes had different profiles, with a higher level for Prader-Willi than for Down and Fragile-X; the intra-profile disharmony was lower in Down and higher in Williams syndrome. Discriminant analysis allowed us to detect the best discriminating subtests in the classification of syndromes based on cognitive points of strengthand weakness. Our results supported the hypothesis that Intellectual Disability reflects the impaired functioning of a complex system in which some skills are damaged more than others. The question of "what discriminates better among syndromes" may be answered assuming a "modular" perspective of mind in disability. To analyze what abilities are specifically impaired in each syndrome, is useful to plan specific rehabilitation procedures.