Evidence for linkage disequilibrium between the dopamine transporter and bipolar disorder.
A role for the dopamine transporter (DAT) in bipolar disorder is implicated by several lines of pharmacological evidence, as well as suggestive evidence of linkage at this locus, which we have reported previously. In an attempt to identify functional mutations within DAT contributing a susceptibility to bipolar disorder, we have screened the entire coding region, as well as significant portions of the adjacent non-coding sequence. Though we have not found a definitive functional mutation, we have identified a number of single nucleotide polymorphisms (SNPs) that span the gene from the distal promoter through exon 15. Of the 39 SNPs that are suitable for linkage disequilibrium (LD) studies, 14 have been analyzed by allele-specific PCR in a sample of 50 parent-proband triads with bipolar disorder. A haplotyped marker comprised of five SNPs, spanning the region between exon 9 and exon 15, was constructed for each individual, and transmission/disequilibrium test (TDT) analysis revealed this haplotype to be in linkage disequilibrium with bipolar disorder (allele-wise TDT p = 0.001, genotype-wise TDT p = 0.0004). These data replicate our previous finding of linkage to markers within and near DAT in a largely different family set, and provide further evidence for a role of DAT in bipolar disorder. Published 2001 Wiley-Liss. Inc.
Greenwood
T A
TA
Departments of Psychiatry, University of California, San Diego and San Diego VA Medical Center, San Diego, California.
Alexander
M
M
Keck
P E
PE
McElroy
S
S
Sadovnick
A D
AD
Remick
R A
RA
Kelsoe
J R
JR
D000483:Alleles; D001714:Bipolar Disorder / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D050483:Dopamine Plasma Membrane Transport Proteins; D005091:Exons; D005192:Family Health; D005260:Female; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D005819:Genetic Markers; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human