Cloninger's type II is a severe, early-onset, male-limited, genetically influenced, impulsive form of alcoholism. We assessed the association of two gene polymorphisms (TaqI A DRD2 and 5-HTTpro) with Cloninger's typology, as defined by age at onset of alcohol-related problems, and family history of alcohol abuse, which is thought to be more frequent in type II alcoholics.

58 male alcohol dependent patients were discriminated according to age at onset of alcohol-related problems and interviewed about family history of alcoholism. Genomic DNA was extracted and PCR amplifying the studied polymorphisms were performed. The associations between DRD2 (A1 or A2 alleles), 5-HTTpro (L and S alleles), family history and typology were assessed by Pearson chi2 analyses.

While typology was not influenced by any of the studied polymorphisms, a higher rate of general family history of alcohol abuse was still observed in type II patients (χ2= 4.53; p = 0.033). Furthermore, the A1 allele of the DRD2 was significantly associated with paternal history of alcoholism (χ2= 4.66; p = 0.031) and male, first-degree, collateral history of alcoholism (χ2= 4.40; p = 0.036).

Age at onset as main discriminator between type I and type II does not seem to be influenced by TaqI A DRD2 and 5-5HTTpro polymorphisms. However, the A1 allele of the DRD2 may be a marker of male familial alcoholism, which is in line with previous studies showing association between TaqI A DRD2 with some clinical features of type II alcoholism.