Abstract
Objective: The neurotrophine “brain derived neurotrophic factor” (BDNF) which is expressed in the brain is responsible for neuronal survive and functioning also plays a role in pathophysiology of alcohol dependence that show multifactorial and polygenic heredity. In the current study, we aimed to identify whether the functional Val66Met [G196A; (rs6265)] polymorphism in BDNF gene has effect upon tendency to alcoholism in Turkish male and female alcohol dependent cases. Methods: Genotype distribution and allele frequency of BDNF Val66Met polymorphism was identified via PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) method in 110 alcoholic cases (10 female, 100 male) and 376 healthy subjects (148 female, 228 male) constituting our study and control groups, statistical analyses were revealed by chi-square and ANOVA tests. Results: The distribution of the mutant AA genotype was 3.6% to 1.6% and frequency of the A allele was 16.0% to 15.0% in the study group when compared to control group. Our results didn’t show any significant differences in genotype distribution and allele frequencies of polymorphism neither between the study and control groups nor between female case and female controls and male alcoholics and male controls. The power of the study for genotype analysis was set at 80.2%. Conclusion: These results indicate that the polymorphic A allele of BDNF gene is not related with alcoholism in Turkish subjects. But since AA genotyped male subjects’ starting ages of alcohol usage and pathological drinking were detected to be earlier among other genotypes, this gave rise to a conclusion that BDNF polymorphism might be important in the alcoholism phenotype.

Key words: alcohol dependence, brain derived neurotrophic factor, BDNF Val66Met, polymorphism

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Türk alkol baðýmlýlarýnda beyin kaynaklý nörotrofik faktör Val66Met polimorfizminin alkol baðýmlýlýðýna yatkýnlýk üzerine etkisi

Özet
Amaç: Multifaktöriyel ve poligenik kalýtým gösteren alkol baðýmlýlýðýnýn patofizyolojisinde, beyinde ifade edilen ve nöronal yaþam ile iþlevsellikten sorumlu bir nörotrofin olan “beyin kaynaklý nörotrofik faktör” (BDNF) geni de rol almaktadýr. Çalýþmamýzda, BDNF genindeki iþlevsel Val66Met [G196A; (rs6265)] polimorfizminin Türk kadýn ve erkek alkol baðýmlýsý olgularýnýn alkol baðýmlýlýðý yatkýnlýðý üzerine etkisinin olup olmadýðýnýn belirlenmesi amaçlanmýþtýr. Yöntem: Çalýþma ve kontrol gruplarýný oluþturan 110 alkol baðýmlýsý olgu (10 kadýn, 100 erkek) ve 376 saðlýklý bireyde (148 kadýn, 228 erkek) BDNF Val66Met polimorfizminin genotip daðýlýmý ve alel sýklýðý PZR-RFLP (Polimeraz Zincir Reaksiyonu-Restriksiyon Fragment Uzunluk Polimorfizmi) yöntemiyle belirlenmiþ, istatistiksel analizler ki-kare ve ANOVA testleriyle gerçekleþtirilmiþtir. Bulgular: Çalýþma grubunu oluþturan olgular, kontrol grubu olgularýyla karþýlaþtýrýldýðýnda; mutant AA genotipinin daðýlýmý %3.6’ya karþý %1.6 iken, A alelinin sýklýðý %16.0’a karþý %15.0 olarak belirlenmiþtir. Bulgularýmýza göre, çalýþma grubu ve kontrol grubu, kadýn olgular ile kadýn kontroller ve erkek olgular ile erkek kontroller arasýnda genotip daðýlýmý ve alel sýklýðý açýsýndan anlamlý bir fark bulunmamaktadýr. Çalýþmanýn gücü genotip analizi açýsýndan %80.2 olarak hesaplanmýþtýr. Sonuç: Bu bulgular, BDNF geni polimorfik A alelinin Türk olgularda alkol baðýmlýlýðýyla iliþkisinin olmadýðýný göstermektedir. Ancak AA genotipli erkek olgularýn alkol kullanmaya ve sorunlu içiciliðe baþlama yaþýnýn diðer genotiplere göre daha erken olduðunun belirlenmesi, alkol baðýmlýlýðý fenotipinde BDNF polimorfizminin önemli olabileceðini düþündürmektedir.

Anahtar Kelimeler: Alkol baðýmlýlýðý, beyin kaynaklý nörotrofik faktör, BDNF Val66Met, polimorfizm