Serotonergic changes have been associated with alcoholism, while serotonin receptors type 1B (5-HT1B) play an important role in regulating serotonergic neurotransmission.
In conclusion, our findings point to an association between functional variants in the promoter region of the HTR1B gene and alcohol dependence, supporting previous neurobiological evidences of the involvement of HTR1B variations in alcohol-related phenotypes.
Genes that have been previously associated with depression, AD, or other addiction-related phenotypes - such as CDH13, CSMD2, GRID1, and HTR1B - were implicated by nominally significant SNPs.
Our study suggests that neither the 5-HTTLPR gene nor the 5-HT1BG861C polymorphism alone is a risk factor for antisocial alcoholism in Taiwan's Han Chinese population, but that the interaction between both genes may increase susceptibility to antisocial alcoholism.
In conclusion, our findings point to an association between functional variants in the promoter region of the HTR1B gene and alcohol dependence, supporting previous neurobiological evidences of the involvement of HTR1B variations in alcohol-related phenotypes.
Our study suggests that neither the 5-HTTLPR gene nor the 5-HT1B G861C polymorphism alone is a risk factor for antisocial alcoholism in Taiwan's Han Chinese population, but that the interaction between both genes may increase susceptibility to antisocial alcoholism.
We further explored correlation of this 5HT1B gene variant between anxiety-depression alcoholism (ANX/DEP ALC) and antisocial alcoholism (antisocial ALC) subgroups because of the high comorbidity of anxiety-depression, antisocial personality disorder, and AD.
A silent polymorphism (G to C substitution) in the gene encoding the autoreceptor 5-HT1B was linked to antisocial alcoholism in Finnish and an American Indian populations [Lappalainen et al., 1998: Arch Gen Psychiatry 55:989-994].
No significant association of the genotype or allele frequencies of the h5-HTR(1B)G861C locus was observed with diagnoses of alcoholism, bipolar disorder, schizophrenia or a history of a suicide attempt.
The present study evaluated LD across three polymorphic systems at HTR1B and haplotype frequencies and allelic association of these systems with both SD generally and alcohol dependence (AD) specifically, with or without a comorbid antisocial diagnosis.
The 5-HT(1B) receptor gene may thus not be a key component in the genetic background underlying alcohol dependence in human and alcohol preference in rodents, although these results should be considered as preliminary according to the small size of our sample.
Although the association in our study might be due to a type I error, the higher degree of HTR1B allele sharing within both populations could also argue for another alcoholism-relevant gene within the proximity of the HTR1B gene on human chromosome 6.
In the Southwestern American Indian tribe, significant sib pair linkage of antisocial alcoholism to HTR1BG861C (P=.01) was again observed, and there was also significant linkage to D6S284 (P=.01).