Association between BDNF val⁶⁶ met genotype and episodic memory

The val66 met polymorphism of brain derived neurotrophic factor (BDNF) has been associated with variability in episodic memory [Egan et al., 2003]. In an attempt to replicate this finding, we genotyped 206 individuals (92 affected with schizophrenia or a related disorder and 114 unaffected relatives) from the Maudsley Family Study for the BDNF val66 met polymorphism. We analyzed the effect of this polymorphism on episodic memory using the Wechsler Memory Scale, revised version (WMS-R) by regression analysis between the WMS delayed score of logical memory and genotype (corrected for age, sex, and IQ). We found the met66 allele conferred a lower score on the WMS delayed measure (R2 = 0.014 P = 0.09), which was not significant. When cases and unaffected relatives were analyzed separately, met66 was associated with a lower score on the WMS delayed measure in the relatives only (R2 = 0.077 P = 0.01), which is consistent with previous findings.