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.