The neurocognitive phenotype of the 22Q11.2 deletion syndrome: Selective deficit in visual-spatial memory

The 22q 11.2 deletion syndrome (velocardiofacial/DiGeorge syndrome) is asso ciated with a high frequency of learning disabilities. Although previous wo rk has demonstrated that verbal skills are typically better preserved than non-verbal skills on both IQ and academic achievement testing in children w ith this syndrome, such measures are not sufficiently specific to determine a selective cognitive deficit. As part of an ongoing prospective study of patients with this syndrome, 29 children aged 5-17 with confirmed 22q 11.2 deletions were assessed with a comprehensive neuropsychological test batter y, including matched tasks of verbal and visuospatial memory. Results indic ate that 22q patients displayed a selective deficit in visual-spatial memor y, which was mirrored by deficits in arithmetic and general visual-spatial cognition. Further, a dissociation between visual-spatial and object memory was observed, indicating further selectivity of this pattern of deficit, a nd providing evidence for the dissociability of these components of visual cognition. These results indicate that children with 22q11.2 deletions disp lay a specific neurocognitive phenotype, and suggest that this region of Ch romosome 22q11 may harbor a gene or genes relevant to the etiology of nonve rbal learning deficits.