[Polymorphic variants in the cluster of genes encoding trace amine receptors and cognitive functioning in patients with schizophrenia spectrum disorders and healthy controls].

Objective: To evaluate the association of polymorphisms in the TAAR1-9 gene cluster on chromosome 6 with cognitive functions in patients with schizophrenia spectrum disorders and healthy controls.

Material and methods: Patients with schizophrenia spectrum disorders (n=216) and healthy people without a family history of mental disorders (n=240) completed a battery of cognitive tests, from which individual indices of cognitive functioning were derived. Associations of the cognitive index with 22 polymorphisms in the TAAR genes were assessed using ANCOVA controlling for sex, age, genetic structure of the sample, and polygenic risk scores of schizophrenia and intelligence.

Results: An interaction effect between group and genotype on the cognitive index was found at the rs3813355 site in the TAAR5 gene (F=6.68; p=0.010; η²_p=0.02). A post hoc analysis revealed genotype-related differences in the patient group. Homozygotes for the common A allele had a milder cognitive deficit than carriers of the minor G allele (t=2.75; p=0.032; Cohen's d=0.38). The effect of genotype on cognitive index remained significant after the inclusion of disease duration and negative symptoms in the model (F=7.99; p=0.005; η²_p=0.04). Of the individual cognitive indicators, associations with genotype were found for working memory and attention (F=8.25; p=0.005; η²p=0.05), cognitive flexibility (F=5.82; p=0.017; η²_p=0.05) and verbal episodic memory (F=6.75; p=0.011; η²_p=0.05).

Conclusion: The results are consistent with the assumption of the role of the TAAR5 genetic polymorphism in the variability of cognitive deficits in patients with schizophrenia.