Exploring the cognitive phenotype of Kabuki (Niikawa-Kuroki) syndrome.

Background Kabuki syndrome (KS) is a Mendelian disorder, characterised by short stature, facial dysmorphisms and developmental delay and/or intellectual disability. Clarification of the neurocognitive profile in KS may provide directions for education and treatment interventions for KS. Previous studies on cognitive functioning in KS are scarce and have mainly focused on the general level of intelligence. The few more extensive studies suggested weaknesses in language skills, visuoconstruction, perceptual reasoning and speed of information processing. Other relevant domains such as memory, executive functioning and social cognition have not been studied yet. Method This is the first study in which cognitive functioning within multiple domains is systematically explored in 29 participants with KS (age range: 5-48 years) and compared to both norm groups (healthy population) and an appropriate control group of 15 individuals with other genetic syndromes (age range: 6-28 years). Results Compared to the norm groups of the cognitive test manuals, as expected, participants with KS show a weaker performance on all cognitive tests. Comparison with the more appropriate genetic control group indicates weaknesses in visuoconstruction and visual memory and no weaknesses in planning, cognitive flexibility or social cognition. Verbal memory seems to be a relative strength. Conclusions Individuals with KS suffer from specific weaknesses in visuoconstruction, in addition to their intellectual disability/developmental delay. These impairments in visuoconstruction plausibly result from problems in visual perceptual processing, which highlight the importance of the use of auditory cues instead of visual cues in targeted educational support and psychosocial interventions.