Intellectual, adaptive and behavioural characteristics in four patients with 18p deletion syndrome.

Background: The association of behavioural phenotype assessment with cytogenomic characterisation may provide a better comprehension of genotype–phenotype correlations in syndromes caused by chromosomal abnormalities, such as 18p deletion syndrome. Method: We report on four Brazilian patients with 18p deletion syndrome characterised by cytogenomic techniques and detailed neuropsychological evaluation. Intellectual, adaptive and behavioural characteristics were assessed through the Wechsler's Scales, the Vineland‐II Scale and the Child Behaviour Checklist, respectively. Socio‐economic measures including main caretaker educational level and family income as defined by Brazilian criteria for social class classification were also collected to evaluate a possible contribution of environmental factors in neurocognitive variability. Results: Two out of four patients showed intellectual disability (IQ < 70). Wechsler's scale results suggest that in our sample, interpretation of social situations based on observation of non‐verbal behaviour constitute a cognitive strength while judgement of social rules and language skills associated with word knowledge and verbal fluency may be a cognitive weakness. Concerning adaptive behaviour, motor and socialisation domains showed to better develop than communication and daily living skills on the Vineland‐II Scale. Only one patient presented internalising behavioural problems based on the Child Behaviour Checklist. Our results also suggested that socio‐economic status may contribute to overall patient development. Conclusion: Our results suggest that some 18p deletion syndrome patients may present average intellectual performance and that the segment deletion size and some families' socio‐economic conditions may influence cognitive development. [ABSTRACT FROM AUTHOR]