A total of 10,554 subjects underwent gene-disease association analysis, including (i) a discovery sample of 681 African-American (AA) cases with alcoholism (37.2% females; 40.3±7.8 years) and 508 AA controls (66.7% females; 39.6±8.6 years), (ii) a primary replication sample of 1,409 European-American (EA) cases (37.3% females; 38.3±10.2 years) and 1,518 EA controls (70.7% females; 39.4±10.4 years), and (iii) a secondary replication sample of 6,438 Australian family subjects (51.9% females; 46.0±10.0 years; 1,645 affected subjects including 625 females). AA and EA samples came from merged SAGE (dbGaP study accession phs000092.v1.p1) and COGA (dbGaP: phs000125.v1.p1) datasets [5], [6], and Australian sample was OZ-ALC (dbGaP: phs000181.v1.p1) dataset [7]. These datasets were originally collected mainly for study of alcoholism. All Australian subjects were of European ancestry. Affected subjects met lifetime DSM-IV criteria for alcohol dependence [8], and Australian subjects were also measured for alcohol consumption by a quantitative scale. Controls were defined as individuals who had been exposed to alcohol (and possibly to other drugs) at sufficient amounts for a sufficient time, but had never become addicted to alcohol or other illicit substances (lifetime diagnoses).
