genetic alcoholism

7/30/2019 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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genetic alcoholism