UNLABELLED: A polymorphism involving a variable number of tandem repeats (VNTR) has been described in the 3' untranslated region of the gene (SLC6A3) coding for the dopamine transporter (DAT). This polymorphism has 2 common alleles, designated as 10-repeat (*10R) and 9-repeat (*9R), that have been linked with several human clinical phenotypes. Previous investigations of the effects of the SLC6A3 polymorphism on DAT availability in smaller samples of humans have yielded divergent results. METHODS: We assessed genotype at the SLC6A3 promoter VNTR polymorphism in 96 healthy European Americans (age range, 18-88 y) who also underwent SPECT with (123)I-2beta-carbomethoxy-3beta-(4-iodophenyl)tropane (beta-CIT) for measurement of striatal DAT protein availability. A ratio of specific to nondisplaceable brain uptake (i.e., V(3)'' = [striatal -occipital]/occipital), a measure proportional to the binding potential, was derived. For this analysis, 9-9 homozygotes and 9-10 heterozygotes were grouped as SLC6A3 *9R carriers and contrasted with SLC6A3 *10R homozygotes. RESULTS: The SLC6A3 *9R carriers had significantly higher striatal DAT availability (V(3)'') than did the SLC6A3 *10R homozygotes, controlling for age (F(1,93) = 6.25, P = 0.014, analysis of covariance). The *9R carriers (n = 41, 49.8 +/- 19.5 y) had a mean increase in striatal DAT availability of 8.9% relative to the *10R homozygotes (n = 53, 49.9 +/- 19.2 y). Striatal subregion analysis revealed that the effect of DAT genotype was significant for both the caudate and the putamen. CONCLUSION: These results support the interpretation of higher DAT levels in association with the *9R allele in European Americans and may relate to previously observed associations between DAT genotype and neuropsychiatric diseases.
UNLABELLED: A polymorphism involving a variable number of tandem repeats (VNTR) has been described in the 3' untranslated region of the gene (SLC6A3) coding for the dopamine transporter (DAT). This polymorphism has 2 common alleles, designated as 10-repeat (*10R) and 9-repeat (*9R), that have been linked with several human clinical phenotypes. Previous investigations of the effects of the SLC6A3 polymorphism on DAT availability in smaller samples of humans have yielded divergent results. METHODS: We assessed genotype at the SLC6A3 promoter VNTR polymorphism in 96 healthy European Americans (age range, 18-88 y) who also underwent SPECT with (123)I-2beta-carbomethoxy-3beta-(4-iodophenyl)tropane (beta-CIT) for measurement of striatal DAT protein availability. A ratio of specific to nondisplaceable brain uptake (i.e., V(3)'' = [striatal -occipital]/occipital), a measure proportional to the binding potential, was derived. For this analysis, 9-9 homozygotes and 9-10 heterozygotes were grouped as SLC6A3 *9R carriers and contrasted with SLC6A3 *10R homozygotes. RESULTS: The SLC6A3 *9R carriers had significantly higher striatal DAT availability (V(3)'') than did the SLC6A3 *10R homozygotes, controlling for age (F(1,93) = 6.25, P = 0.014, analysis of covariance). The *9R carriers (n = 41, 49.8 +/- 19.5 y) had a mean increase in striatal DAT availability of 8.9% relative to the *10R homozygotes (n = 53, 49.9 +/- 19.2 y). Striatal subregion analysis revealed that the effect of DAT genotype was significant for both the caudate and the putamen. CONCLUSION: These results support the interpretation of higher DAT levels in association with the *9R allele in European Americans and may relate to previously observed associations between DAT genotype and neuropsychiatric diseases.
Authors: A Meyer; D N Klein; D C Torpey; A J Kujawa; E P Hayden; H I Sheikh; S M Singh; G Hajcak Journal: Genes Brain Behav Date: 2012-06-28 Impact factor: 3.449
Authors: M Reimold; M N Smolka; A Zimmer; A Batra; A Knobel; C Solbach; A Mundt; H U Smoltczyk; D Goldman; K Mann; G Reischl; H-J Machulla; R Bares; A Heinz Journal: J Neural Transm (Vienna) Date: 2007-08-22 Impact factor: 3.575
Authors: Mindi A Styn; Tomoko Nukui; Marjorie Romkes; Kenneth Perkins; Stephanie R Land; Joel L Weissfeld Journal: Am J Med Genet B Neuropsychiatr Genet Date: 2009-03-05 Impact factor: 3.568