ADH1B*1, ADH1C*2, DRD2 (-141C Ins), and 5-HTTLPR are associated with alcoholism in Mexican American men living in Los Angeles.
BACKGROUND
The aim of the present study was to use a candidate gene approach to identify the genetic risk factors for alcoholism in Mexican Americans residing in the Los Angeles area. The genes selected include alcohol metabolizing genes and neurotransmitter genes, which have been shown in the literature to be associated with alcoholism in other ethnic groups.


METHODS
Thirteen allelic variants from seven genes were evaluated for their role in alcoholism using alcoholic (n = 200) and nonalcoholic (n = 251) Mexican Americans. Those polymorphic sites include alcohol dehydrogenase (ADH1B, ADH1C), aldehyde dehydrogenase (ALDH2), cytochrome P-450 2E1 (CYP2E1) TaqI, DraI, RsaI, dopamine D2 receptor (DRD2) TaqI A, B, intron 6, exon 7, -141C Ins/Del, serotonin transporter (5-HTTLPR), and GABAA receptor beta3 subunit (GABRbeta3).


RESULTS
The results demonstrate that Mexican Americans have extremely low allele frequency for both ALDH2*2 and ADH1B*2 and a relatively high frequency of ADH1C*2 and CYP2E1 c2 alleles. ADH1B*1, ADH1C*2, DRD2 (-141C Ins), and 5-HTTLPR were associated with alcoholism in Mexican Americans (p < 0.05). DRD2 Ins was associated with alcoholism in those alcoholics who carried the ADH1B*2 or ADH1C*1 protective alleles (p = 0.032 in genotype level and p = 0.015 in allele level). DRD2 TaqI A and B alleles were associated with early age of onset for drinking (p = 0.016 for TaqI A1 and p = 0.049 for TaqI B1 allele).


CONCLUSIONS
Together, the data reveal unique genetic patterns in Mexican Americans that may be in part responsible for the heightened risk for alcoholism and alcohol-associated health problems in this population.
Department of Psychiatry, Harbor-UCLA Medical Center, Torrance, CA, USA.
Tamiko
T
Konishi
Huai-Rong
HR
Luo
Maria
M
Calvillo
Matthew S
MS
Mayo
Keh-Ming
KM
Lin
Yu-Jui Yvonne
YJ
Wan
D000328:Adult; D000368:Aged; D000426:Alcohol Dehydrogenase / Q000235:genetics*; D000437:Alcoholism / Q000235:genetics*; D000483:Alleles; D005787:Gene Frequency / Q000235:genetics; D006801:Humans; D015141:Los Angeles; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics*; D017058:Mexican Americans / Q000235:genetics*; D008875:Middle Aged; D016254:Mutagenesis, Insertional; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D017448:Receptors, Dopamine D2; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; C489332:ADH1B protein, human; C420272:ADH1C protein, human; D000426:Alcohol Dehydrogenase