Evidence of linkage in subtypes of alcoholism

We believed that subtyping alcoholism might be an efficient strategy for ma pping susceptibility genes. Cluster analysis is one of the possible statist ical techniques for such a purpose. We required that, ideally, the variable s to be used in cluster analysis should be: 1) related to alcoholism, 2) re lated to the severity of alcoholism, and 3) familial, i.e., correlated with in families. Only three variables met all three conditions. Those included age of onset of ALDX1, smoking, and TPQ-HA. A global score of symptoms of a lcoholism was systematically introduced as one of the variables composing a subset for cluster analysis, although this score did not show any familial aggregation. Our strategy led to a strong evidence of linkage at D15S230 i n only 20 families whose members are mainly characterized by heavy smoking. (C) 1999 Wiley-Liss, Inc.