Evidence of association of KIBRA genotype with episodic memory in families of psychotic patients and controls

The first genome-wide association study of human memory identified an association between a common T/C polymorphism of the KIBRA gene (rs17070145) and episodic memory performance in normal individuals; subsequent studies have implicated the same polymorphism in Alzheimer’s disease. Since impaired neurocognitive performance, including memory, may be both a core feature of schizophrenia and a candidate endophenotype, we attempted to replicate this association in a total sample of 544 subjects (including patients with psychosis, their unaffected relatives as well as normal individuals). In the combined sample there was a significant association between the KIBRA T allele and better performance in the single principle component of the memory measures, which included immediate and delayed logical and visual memory from the Wechsler Memory Scale (p = 0.019). In the unaffected individuals (patients’ relatives and healthy controls) we observed an association of KIBRA with immediate and delayed logical memory (p = 0.020 and 0.025, respectively), while in patients with psychosis with delayed visual memory (p = 0.05). This study replicates the association between the KIBRA gene and episodic memory and suggests a possibly differential effect of the polymorphism in psychotic and non-psychotic individuals.