genetic alcoholism
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Genetic
Alcoholism
Submitted
by:
Lovely Garg
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Definition ofAlcoholism
Alcoholism is a primary, chronic
disease with genetic,
psychosocial, and environmentalfactors influencing its
development and manifestations
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INTRODUCTION
Alcohol dependence is a complex
disorder
Many pathways lead to thedevelopment of alcohol dependence
Many genes are likely involved in the
development of alcohol dependence
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Why study the genetics ofAlcoholism
The genetic risk for alcoholism is high; it runs
in families.
Identifying genetic factors that influence risk
and protection for alcoholism may lead to
better interventions.
But, study is difficult because the influence is
not monogenic alcoholism does not exhibit a
Mendelian pattern of inheritance
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Variance of Risk
Environment
40%
Genetics
60%
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Major cause of death
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Data supporting geneticinfluences
4-Fold increase in close relatives
(e.g. Children, Siblings)
Identical v/s Fraternal twinsAdopted away children still have a 4-
fold increase in risk
Work with genetic animal models
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Rate of Alcoholism as a Function of Family
History Among Current Drinkers
0
10
20
30
40
%alcoholic
Females
Males
Rate of Alcoholism as a Function of Family
History Among Current Drinkers
0
10
20
30
40
%alcoholic
Females
Males
Source: Dawson
et al., 1992
FHP2 = hxalcoholism1st degreerelativesonly.
FHN= nofam hx of
alcoholism
FHP1= hxalcoholism
2nd or 3rd
degree
relatives
only
FHP3 = hxalcoholism1st degreerelatives +either 2nd/3rddegree
relatives
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Alcoholics among relatives of
alcoholics
0
10
20
30
40
Genera
lPopul
ation
Pate
rnalal
coholis
m
Mate
rnalal
coholis
m
Fratern
altwin
s
Identic
altwin
s
Percent
alcoholic
Male
Female
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What Genes have been found
from human Research
-aminobutyric acid type A (GABAA) receptor
genes.
A muscarinic cholinergic receptor gene
(CHRM2).
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The GABAA Receptor
GABA is a widely-distributed inhibitorychemical in the brain that dampens nerve cellactivity.
The GABAA receptor is a pentameric moleculethat forms a chloride ionophore.
Alcohol enhances the effects of GABA by
acting at the GABAA receptor.
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GABA Genes and Alcohol
Human Chr 5; Mouse Chr 11:GABRA1 (Gabra1), GABRA6 (Gabra6),GABRB2, and GABRG2 (Gabrg2)
Human Chr 15: GABRG3 Human Chr 4: GABRA2
The ones shown in both CAPS and lower case
are supported by evidence from both humanand mouse studies
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Other Genes
Too many to list, and with varying levels ofsupport.
Examples:
CHRM2
muscarinic cholinergic receptor
DRD2 dopamine D2 receptor
GAL the neuropeptide, galanin
OPRM1 mu opioid receptorhTAS2R16 a taste receptor for bittersubstances
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