Brain-derived neurotrophic factor Val/Met polymorphism and bipolar disorder. Association of the Met allele with suicidal behavior of bipolar patients.
OBJECTIVE
The substitution of valine by methionine in the brain-derived neurotrophic factor (BDNF Val/Met) gene alters the intracellular trafficking and regulated secretion of BDNF. This study tested whether the BDNF Val/Met polymorphism is associated with bipolar disorder in Korean subjects, and whether clinical features vary according to genotype.


METHODS
The allelic and genotypic distributions of BDNF Val/Met were determined in a population of 169 bipolar patients and 251 normal controls. Between-genotype comparisons of clinical features were performed without a priori knowledge of the genotype of individual patients.


RESULTS
Allelic distributions did not differ significantly between bipolar patients and controls (chi(2) = 0.400, p = 0.821). However, the rate of suicide attempts among the Val/Val (11.3%), Val/Met (28.8%) and Met/Met (38.9%) genotype groups were significantly different (chi(2) = 9.879, p = 0.007). Relative to patients with the Val/Val genotype, those with the Met/Met genotype had a 4.9-fold higher risk of suicide attempts (95% CI, 1.7-14.7).


CONCLUSIONS
These findings suggest that BDNF Val/Met is related to the suicidal behavior of bipolar patients, and may have clinical relevance as a biological indicator of bipolar patients at risk of suicide.
Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Byungsu
B
Kim
Chang Yoon
CY
Kim
Jin Pyo
JP
Hong
Seong Yoon
SY
Kim
Chul
C
Lee
Yeon Ho
YH
Joo
D000328:Adult; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000235:genetics* / Q000523:psychology; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D016009:Chi-Square Distribution; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006103:Granuloma, Lethal Midline / Q000235:genetics*; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics*; D008875:Middle Aged; D013405:Suicide / Q000523:psychology; D014633:Valine / Q000235:genetics*
D019208:Brain-Derived Neurotrophic Factor; D008715:Methionine; D014633:Valine