The human dopamine transporter gene: the 5'-flanking region reveals five diallelic polymorphic sites in a Caucasian population sample.

The 5'-flanking region of the human dopamine transporter (hDAT) was systematically screened for variants by single strand conformation analysis (SSCA) between -1586 and +97 basepair (bp) relative to the transcription start site. Five diallelic polymorphisms were found, which were shown to be due to single base substitutions: T-67A, G-660C, C-839T, C-1169G, T-1476G. In a population sample of 119 unrelated Caucasians, allele frequencies of the rarer allele were 47% for -67T, 3% for -660C, 45% for -839T, 50% for -1169G, and 8% for -1476G, respectively. Among 15 observed haplotypes, seven haplotypes collected a frequency of about 96% in our sample. T-67A, C-839T, C-1169G, T-1476G were related to potential transcriptional recognition sites. These findings and the occurrence of distinct haplotypes at the hDAT promoter locus in a Caucasian population sample make this region a promising target in the context of linkage and association studies in certain diseases.