Table 3. Family-Based Association - GABRA SNP rs279871 and CD/AUD Phenotypes and Power Calculations.

Phenotype	Offset	Allele	Allele freq	famnum	Z	P
CD	0.l	1/A	0.53	164	−0.70	0.48
CD sx ct	0	1/A	0.53	180	0.11	0.91
AD	0.1	1/A	0.53	147	0.20	0.84
AUD	0.1	1/A	0.53	158	−0.65	0.52

Power Calculations
Model	Odds Ratio	Power
Additive	1.02	5%
	2.00	86%
	3.90	99%
Multi	1.02	5%
	2.00	98%
	3.90	100%
Recessive	1.02	5%
	2.00	35%
	3.90	74%
Dominant	1.02	5%
	2.00	66%
	3.90	99%

CD = at least 3 DSM-III-R conduct disorder criteria (lifetime); CD sx ct = DSM-III-R conduct disorder symptom count corrected for age within sex; AD = DSM-IV-defined alcohol dependence (lifetime); AUD = DSM-IV-defined alcohol use disorder (lifetime). Power Calculation assumptions included: (1) population prevalence of disease = 0.1; (2) α = 0.05 ; (3) an A-allele frequency of 0.53; and (4) disease locus = marker locus. CD Phenotype = categorical outcome variable, requiring at least three DSM-III-R conduct disorder criteria; Odds Ratio refers to the increased odds of meeting the three conduct disorder symptom threshold based on genotypic differences; Power refers to the probability of concluding there is a genetic association, given a true association exists (and given described assumptions).