Cognitive correlates of a functional COMT polymorphism in children with 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11DS) is a common microdeletion syndrome associated with a markedly elevated risk of schizophrenia in adulthood. Cognitive impairments such as a low IQ and deficits in attention and executive function are common in childhood. The catechol O-methyltransferase (COMT) gene maps the deleted region and is involved in the degradation of dopamine, a neurotransmitter thought to be important in cognition and development of schizophrenia. Thus, we examined the correlation neurocognitive deficits and a common polymorphism Val¹⁵⁸Met in the COMT gene in a cohort of children with 22q11DS. Our results show that children with 22q11DS who have the Met allele have higher IQ and achievement scores and perform better on measures of prefrontal cognition, such as the Continuous performance Task, as compared with those with the Valallele. These results confirm that the hemizygous COMT Val¹⁵⁸Met genotype impacts upon cognition in children with 22q11DS.