Reference 
Allele Change 
Risk Allele 
Statistical Values 
Author Comments 
Result of Statistical Analysis 
Li D, 2006 
2/3/4/5/7 repeat 

2R: overall P(Z) Pvalue=0.6059, heterogeneity P(Q) Pvalue=......
2R: overall P(Z) Pvalue=0.6059, heterogeneity P(Q) Pvalue=0.2157, publication bias P(T) Pvalue=0.204, overall OR=0.97; Heterogeneity test between design types, P(Q) Pvalue=0.9574, Heterogeneity test between sample ethnicities, P(Q) Pvalue=0.8673. 3R: overall P(Z) Pvalue=0.9507, heterogeneity P(Q) Pvalue=0.3767, publication bias P(T) Pvalue=0.891, overall OR=0.99; Heterogeneity test between design types, P(Q) Pvalue=0.5912, Heterogeneity test between sample ethnicities, P(Q) Pvalue=0.5213. 4R: overall P(Z) Pvalue=0.0042, heterogeneity P(Q) Pvalue=0.0513, publication bias P(T) Pvalue=0.07, overall OR=0.9; Heterogeneity test between design types, P(Q) Pvalue=0.01, Heterogeneity test between sample ethnicities, P(Q) Pvalue=0.1345. 5R: overall P(Z) Pvalue=0.0053, heterogeneity P(Q) Pvalue=0.2067, publication bias P(T) Pvalue=0.29, overall OR=1.68; Heterogeneity test between design types, P(Q) Pvalue=0.2958, Heterogeneity test between sample ethnicities, P(Q) Pvalue=0.9445. 7R: overall P(Z) Pvalue=2E12, heterogeneity P(Q) Pvalue=0.0314, publication bias P(T) Pvalue=0.062, overall OR=1.34; Heterogeneity test between design types, P(Q) Pvalue=0.0017.
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2 repeat and 3 repeat showed no significant association, 4 r......
2 repeat and 3 repeat showed no significant association, 4 repeat, 5 repeat and 7 repeat showed a significant association with ADHD
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Significant

Mill J, 2003 


TRANSMIT Pvalue>0.05
TRANSMIT Pvalue>0.05

no evidence of biased transmission to ADHD probands was foun......
no evidence of biased transmission to ADHD probands was found
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Nonsignificant

Swanson JM, 1998 
27 repeats 
7repeat 
HRR P<0.035 (df=1)
HRR P<0.035 (df=1)

The result provides additional evidence that the DRD4 gene i......
The result provides additional evidence that the DRD4 gene is associated with a refined phenotype of ADHD.
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Significant

Rowe DC, 1998 
29 repeats 
7repeat 
Genotype frequency test: P=0.0151 for ADHDC type; P=0.0319 ......
Genotype frequency test: P=0.0151 for ADHDC type; P=0.0319 for ADHDIA type. Correlations of continuous symptom counts: in total sample, r=0.19 (P<0.01), race adjusted r=0.19 (P<0.01) for HI symptoms; race/age adjusted r=0.16 (P<0.01), r=0.21 (P<0.01), race adjusted r=0.20 (P<0.01) for IA symptoms. In any diagnosis sample, race adjusted r=0.16 (P<0.05) for HI symptoms; r=0.22 (P<0.01), race adjusted r=0.21 (P<0.01) for IA symptoms.
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In an association test, the 7repeat allele occurred more fr......
In an association test, the 7repeat allele occurred more frequently in children with ADHDinattentive type than in control children. In genetically discordant sibling pairs, the sibling with a greater number of 7repeat alleles displayed more inattentive symptoms than his/her cosibling with fewer 7repeat alleles. For ADHDcombined type, the 7repeat allele frequency was greater than that in the control sample. However, a quantitative transmission disequilibrium test yielded no significant linkage of the 7repeat allele with hyperactiveimpulsive symptoms. A categorical TDT yielded no significant findings.
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Significant

Smalley SL, 1998 
28 repeats 
7repeat 
TDT test and attributable risk (AR): P=0.03, AR=1.5 for Tota......
TDT test and attributable risk (AR): P=0.03, AR=1.5 for Total sample; P=0.02, AR=1.6 for DSMIIIR definite; P=0.03, AR=1.5 for DSMIV definite; P=0.15, AR=1.6 for Inattentive; P=0.11, AR=1.4 for Hyper/combined; P=0.04, AR=1.5 for Affected males; P=0.4, AR=1.3 for Affected females; P=0.07, AR=1.5 for Caucasian only.
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Using the TDT in the total sample, the 7 allele is different......
Using the TDT in the total sample, the 7 allele is differentially transmitted to ADHD children (P=0.03) while the mean test revealed no evidence of increased IBD sharing among ASPs.
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Significant

Cheuk DK, 2006(a) 


2R: Pvalue=0.07, OR=0.52; TDT Pvalue=0.65; 4R: Pvalue=0.2......
2R: Pvalue=0.07, OR=0.52; TDT Pvalue=0.65; 4R: Pvalue=0.2, OR=1.51; TDT Pvalue=0.33; 3R/5R/6R: no Pvalue; 7R: Pvalue=0.66, OR=2.01; TDT Pvalue=0.99;
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not significantly associated with ADHD
not significantly associated with ADHD

Nonsignificant

Castellanos FX, 1998 
27 repeats 
7R 
chisquare Pvalue=0.81, X^{2} (1df) =0.06 for the f......
chisquare Pvalue=0.81, X^{2} (1df) =0.06 for the frequency of 7R allele between cases and controls, Pvalue=0.66, X^{2} (1df) =0.19 for the frequency of short (25 repeats) vs long (6 or 7 repeats); genotypic chisquare Pvalue=0.31, X^{2} (8df) =9.35, Pvalue=0.25, X^{2} (1df) =1.31 for the frequency of genotype 4.4 vs 4.7
More...

There was no significant differences between patients and ps......
There was no significant differences between patients and psychiatrically screened controls in the frequency of the DRD*7R allele nor in any other of the DRD4 alleles; patients and controls did not differ significantly in frequency of individual genotypes, in the frequency of genotype 4.4 vs 4.7 or in the frequency of short vs long alleles
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Nonsignificant

Smith KM, 2003 


Genotype groupings chisquare Pvalue=0.148, Allele grouping......
Genotype groupings chisquare Pvalue=0.148, Allele groupings chisquare Pvalue=0.11
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revealed a trend towards a lower frequency of the 4/4 genoty......
revealed a trend towards a lower frequency of the 4/4 genotype in the ADHD group
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Nonsignificant

Faraone SV, 1999 
28 repeats 
7R 
TDT Pvalue=0.03 indicating that one or more alleles were pr......
TDT Pvalue=0.03 indicating that one or more alleles were preferentially transmitted to the ADHD child; chisquare Pvalue=0.007, X^{2}=7.4, df=1 for 7repeat allele; logistic regression Pvalue=0.01, Z=2.5 for 7repeat allele as a predictor of the diagnosis of ADHD
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suggested an association between ADHD and the DRD4 7repeat ......
suggested an association between ADHD and the DRD4 7repeat allele; the number of 7repeat alleles predicted the diagnosis of ADHD
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Significant

Comings DE, 1999 
28 repeats 

chisquare Pvalue=0.0003, X^{2}(6df)=25.50 for alle......
chisquare Pvalue=0.0003, X^{2}(6df)=25.50 for allele counts; chisquare Pvalue=0.194, X^{2}(1df)=1.68 for frequency of the 7 allele or 5 to 8 alleles in ADHD compared with controls; chisquare Pvalue=0.010, X^{2}(1df)=6.64 for 24 versus 58 alleles
More...

the distributions were significant for ADHD when the total s......
the distributions were significant for ADHD when the total set of alleles was compared in a 2x7 chisquare test of total controls versus index groups; none of the subject groups were significant for the frequencies of the 7 alleles; the results were significant for ADHD by pooling the 5, 6, 7, and 8 alleles
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Significant

SanchezMora C, 2011 


chisquare test Pvalue>0.05 for allele and genotype frequen......
chisquare test Pvalue>0.05 for allele and genotype frequencies from each separate site; metaanalysis: Pvalue=0.78, OR=0.97 for 4R4R genotype versus others; Pvalue=0.52, OR=1.12 for 7R7R genotypes versus others; Pvalue=0.53, OR=0.87 for 4R7R genotypes versus others
More...

no significant association between the 48bp VNTR and ADHD wa......
no significant association between the 48bp VNTR and ADHD was identified in any of the European samples when studied separately; no association between the VNTR polymorphism and adult ADHD was seen in the full ADHD sample in the metaanalysis
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Nonsignificant

Tahir E, 2000 (b) 
28 repeat 
7repeat 
TDT onetailed Pvalue=0.047
TDT onetailed Pvalue=0.047

suggestive evidence for DRD4*7 was found
suggestive evidence for DRD4*7 was found

Significant

TovoRodrigues L, 2011 
4, 7 repeat 

Haplotypic distribution analysis by Fisher's exact test: Pv......
Haplotypic distribution analysis by Fisher's exact test: Pvalue=0.031 for 7R rare haplotypes, Pvalue=0.086 for 4R; variability test, Pvalue=0.01 for 7R haplotype distribution, Pvalue=0.149 for 4R; nucleotide changes test, Pvalue=0.008 for total substitutions of 7R ADHD group, Pvalue=0.043 for nonsynonymous substitutions of 7R ADHD group.
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An excess of rare variants were observed in the 7R alleles o......
An excess of rare variants were observed in the 7R alleles of ADHD patient when compared with controls. This difference was not observed in 4R allele. Furthermore, nucleotide changes that predict synonymous and nonsynonymous substitutions were more common in the 7R sample.
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Significant

Eisenberg J, 2000 
28 repeat 

HRR Pvalue<0.1
HRR Pvalue<0.1

No preferential transmission of the long DRD4 alleles was ob......
No preferential transmission of the long DRD4 alleles was observed
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Nonsignificant

Barr CL, 2000 (b) 
27 repeat 

TDT onesided Pvalue=0.045, TDT twosided Pvalue=0.090
TDT onesided Pvalue=0.045, TDT twosided Pvalue=0.090

It is significant using the onesided P value but not the tw......
It is significant using the onesided P value but not the twosided P value
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Significant

Bidwell LC, 2011 
24, 7 repeat 
7repeat 
FBATGEE: total ADHD, Pvalue=0.007 for 4repeat allele (pos......
FBATGEE: total ADHD, Pvalue=0.007 for 4repeat allele (positive association), Pvalue=0.05 (negative association) for 7repeat allele; Inattentive, Pvalue=0.007 (positive association) for 4repeat allele, Pvalue=0.21 for 7repeat allele; Hyperactive/impulsive, Pvalue=0.003 (positive association) for 4repeat allele, Pvalue=0.08 for 7repeat allele
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the 4repeat allele significantly associated with common ADH......
the 4repeat allele significantly associated with common ADHD phenotype and both the inattentive and hyperactiveimpulsive symptom dimensions.
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Significant

Muglia P, 2000 
7/non7repeat 
7repeat 
casecontrol: allele chisquare test Pvalue=0.01; familyba......
casecontrol: allele chisquare test Pvalue=0.01; familybased: TDT Pvalue=0.15; combined z score=2.68, Pvalue=0.003
More...

casecontrol analysis showed a significantly higher presence......
casecontrol analysis showed a significantly higher presence of the 7repeat in the adult ADHD patients vs. controls. TDT test in nuclear families showed a trend toward a increased transmission of the 7repeat from the heterozygous parents to the affected offspring. After combined, the overall significance was stronger.
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Significant

Hawi Z, 2000 (a) 
28 repeat; short(24)/long(58) 

HHRR Pvalue=0.95 for allele 7repeat; Pvalue=0.95 when com......
HHRR Pvalue=0.95 for allele 7repeat; Pvalue=0.95 when comparing short repeats and long repeats
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no significant evidence for biased transmission
no significant evidence for biased transmission

Nonsignificant

Kotler M, 2000 
28 repeats, short(25)/long(68) 

HRR test: Pvalue=0.02 for current 49 triads, Pvalue=0.05 f......
HRR test: Pvalue=0.02 for current 49 triads, Pvalue=0.05 for combined 98 triads; Pvalue=0.17 for ADHD combined type; Pvalue=0.15 for inattentive type
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there is a significant excess of the DRD4 long repeat in the......
there is a significant excess of the DRD4 long repeat in the HRR control group
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Significant

Kustanovich V, 2004 

7 repeat 
GRR=1.4, TDT Pvalue=0.137
GRR=1.4, TDT Pvalue=0.137

not significantly associated with ADHD
not significantly associated with ADHD

Nonsignificant

Das M, 2011 
27R 

ETDT Pvalue=0.7, X^{2}(1df)=0.14, RR=1; allelic fre......
ETDT Pvalue=0.7, X^{2}(1df)=0.14, RR=1; allelic frequencies COCAPHASE Pvalue=0.83, X^{2}=0.04 for 2R. ETDT Pvalue=1, X^{2}(1df)=0, RR=1.1; allelic frequencies COCAPHASE Pvalue=0.81, X^{2}=0.06 for 3R. ETDT Pvalue=0.47, X^{2}(1df)=0.51, RR=1.1; allelic frequencies COCAPHASE Pvalue=0.92, X^{2}=0.008 for 4R. ETDT Pvalue=0.31, X^{2}(1df)=1.05, RR=0.42; allelic frequencies COCAPHASE Pvalue=0.38, X^{2}=0.77 for 5R. ETDT Pvalue=0.1, X^{2}(1df)=2.64, RR=2.27; allelic frequencies COCAPHASE Pvalue=0.16, X^{2}=2.01 for 6R. ETDT Pvalue=0.41, X^{2}(1df)=0.68, RR=2.22; allelic frequencies COCAPHASE Pvalue=0.55, X^{2}=0.35 for 7R.
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no significant contribution was noticed by either casecontr......
no significant contribution was noticed by either casecontrol or familybased analysis for 25R; no significant contribution was noticed by casecontrol analysis; ETDT analysis revealed higher transmission from parents to ADHD probands with higher relative risk for 6R and 7R.
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Nonsignificant

Holmes J, 2000 
27, 9 repeat 
7repeat 
Casecontrol analysis: overall Pvalue=0.01, Pvalue=0.001 f......
Casecontrol analysis: overall Pvalue=0.01, Pvalue=0.001 for allele 7; TDT analysis: overall Pvalue=0.31
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There was strong evidence of a difference in distribution. P......
There was strong evidence of a difference in distribution. Possession of the candidate allele 7 is significantly more common in ADHD cases than in the controls. But from the combined regression analysis (TDT analysis), there was no overall evidence of association between DRD4 and ADHD.
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Significant

ArcosBurgos M, 2004 (b) 
7 repeat 

twopoint LOD=3.18 under model I, twopoint LOD=4.74 under......
twopoint LOD=3.18 under model I, twopoint LOD=4.74 under model II, twopoint LOD=3.21 under model III, NPL Pvalue=0.4194, PDT smallest Pvalue=0.0578 for 7R
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Twopoint LOD scores were significantly negative; Nonparame......
Twopoint LOD scores were significantly negative; Nonparametrical analysis resulted in nonsignificant evidence for linkage
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Nonsignificant

McCracken JT, 2000 
7/non7repeat 
7repeat 
TDT Pvalue=0.297 for total sample
TDT Pvalue=0.297 for total sample

no significant evidence for biased transmission
no significant evidence for biased transmission

Nonsignificant

Brookes KJ, 2008(c) 
2/4/7 repeat 

2R: Pvalue=0.87, OR=1.08 in London; Pvalue=0.29, OR=0.68 i......
2R: Pvalue=0.87, OR=1.08 in London; Pvalue=0.29, OR=0.68 in Cardiff; Pvalue=0.11, OR=1.6 in Dublin; Pvalue=0.56, OR=0.92 in IMAGE; Pvalue=0.86, OR=0.97 in combined. 4R: Pvalue=0.37, OR=0.9 in London; Pvalue=0.23, OR=1.27 in Cardiff; Pvalue=0.04, OR=0.74 in Dublin; Pvalue=0.35, OR=0.92 in IMAGE; Pvalue=0.17, OR=0.92 in combined. 7R: Pvalue=0.33, OR=1.2 in London; Pvalue=0.91, OR=0.97 in Cardiff; Pvalue=0.2, OR=1.24 in Dublin; Pvalue=0.09, OR=1.19 in IMAGE; Pvalue=0.04, OR=1.18 in combined
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2R is not significantly associated in all samples; significa......
2R is not significantly associated in all samples; significant association was detected in Dublin sample for 4R; 7R is significantly associated with ADHD in the combined dataset
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Significant

Sunohara GA, 2000 

7repeat 
TDT test: Pvalue=0.045 for Toronto families, Pvalue=0.013 ......
TDT test: Pvalue=0.045 for Toronto families, Pvalue=0.013 for previously reported Irvine families, Pvalue=1.0 for new Irvine families, Pvalue=0.028 for combined Irvine families, Pvalue=0.006 for combined Irvine and Toronto families
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Biased transmission of the 7repeat allele from parents to A......
Biased transmission of the 7repeat allele from parents to ADHD probands and their affected siblings was observed in the 2 new samples of families collected in Toronto and Irvine and for these samples combined with the 52 families previously reported from Irvine.
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Significant

Nyman ES, 2007 


No available information.
No available information.

No evidence of association was seen.
No evidence of association was seen.

Nonsignificant

Qian Q, 2007 


Chisquare test: long and shortrepeat genotype analysis: P......
Chisquare test: long and shortrepeat genotype analysis: Pvalue=0.004 for Male ADHD, Pvalue=0.006 for male ADHDC, Pvalue=0.033 for male ADHDI, Pvalue=0.016 for male ADHD for refined phenotype, Pvalue=0.480 for female ADHD; long and shortrepeat allele analysis: Pvalue=0.021 for Male ADHD, Pvalue=0.031 for male ADHDC, Pvalue=0.055 for male ADHDI, Pvalue=0.027 for male ADHD for refined phenotype, Pvalue=0.033 for female ADHD
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When stratified by gender, the longrepeat genotypes and all......
When stratified by gender, the longrepeat genotypes and alleles were found more frequently in male ADHD probands than in male controls. The same results were found for males with the ADHDC subtype. In contrast, longrepeat alleles occurred less frequently in female ADHD subjects than in female controls
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Significant

Bakker SC, 2005 

7R 
allelic TDT Pvalue=0.50
allelic TDT Pvalue=0.50

no signs of a distorted transmissions of any of the single p......
no signs of a distorted transmissions of any of the single polymorphisms, or of single alleles
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Nonsignificant

Qian Q, 2004 
short(23R)/long(46R) 

casecontrol genotype X^{2} test: Pvalue=0.004 (OR=......
casecontrol genotype X^{2} test: Pvalue=0.004 (OR=2.846, 95%CI=1.3496.003) for maleADHD, Pvalue=0.006 (OR=3.964, 95%CI=1.38611.341) for maleADHDC, Pvalue=0.033 for maleADHDI, Pvalue=0.48 for femleADHD; casecontrol allele X^{2} test: Pvalue=0.021 (OR=1.572, 95%CI=1.0682.313) for maleADHD, Pvalue=0.031 (OR=1.665, 95%CI=1.0452.655) for maleADHDC, Pvalue=0.055 for maleADHDI, Pvalue=0.033 (OR=0.446, 95%CI=0.2100.949)for femleADHD; HHRR Pvalue=1; ETDT P>0.05
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no evidence of casecontrol differences in allelic frequenci......
no evidence of casecontrol differences in allelic frequencies, but the longrepeat genotypes and alleles were found more frequently in male ADHD probands than in male controls; no overall evidence of association between SLC6A31 and ADHD according to HHRR analysis; no preferential transmission of any allele were found by ETDT test.
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Significant

Faraone SV, 2001 

7R 
casecontrol metaanalysis: Pvalue<0.001, Z=5.2, combined e......
casecontrol metaanalysis: Pvalue<0.001, Z=5.2, combined estimate=1.9; combined estimate OR=1.72.0 in the sensitivity analysis; publication bias, Pvalue=0.81, statistic=0.2, t=0.2, df=7. familybased metaanalysis: Pvalue=0.02, Z=2.3, combined estimate=1.4; combined estimate OR=1.31.4 in the sensitivity analysis; publication bias, Pvalue=0.62, statistic=0.6, t=0.5, df=13
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both the casecontrol and familybased studies supported for......
both the casecontrol and familybased studies supported for the association between ADHD and DRD4 7 repeat; no evidence that this association was accounted for by any one study, and there was no evidence for publication bias.
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Significant

Gornick MC, 2007 
28 repeat 

2R: casecontrol test Pvalue=0.632, OR=1, TDT test Pvalue=......
2R: casecontrol test Pvalue=0.632, OR=1, TDT test Pvalue=0.622; 3R: casecontrol test Pvalue=0.758, OR=0.81; TDT test Pvalue=0.429; 4R: casecontrol test Pvalue=0.04, OR=0.82; TDT test Pvalue=0.758; 5R: casecontrol test Pvalue=0.108, OR=0.21; TDT test Pvalue=1; 6R: casecontrol test Pvalue=0.048; TDT test Pvalue=0.239; 7R: casecontrol test Pvalue=0.028, OR=1.19; TDT test Pvalue=0.628; 8R: casecontrol test Pvalue=0.163
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No frequency difference was found between case and control f......
No frequency difference was found between case and control for 2R, 3R, 5R, 6R and 8R; the controls had a higher frequency of the 4repeat allele, but the associationwas not confirmed in the TDT analyses; The DRD4 7repeat allele was significantly more frequent in ADHD cases than controls, but the associationwas not confirmed in the TDT analyses.
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Significant

Carpentier, P. J., 2012 

7R 
genotypic Pvalue=0.16, adj OR=0.78, 95%CI=0.551.10; Pvalu......
genotypic Pvalue=0.16, adj OR=0.78, 95%CI=0.551.10; Pvalue=0.58, adj OR=1.10, 95%CI=0.791.52 with gender as the covariate
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No significant association was found for the risk allele car......
No significant association was found for the risk allele carriers in the ADHD_all group compared to the control group. The covariate Gender had no significant effect.
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Nonsignificant

Todd RD, 2001(b) 


ETDT Pvalue=0.86, X^{2}(7df)=3.3 in DSMIV inattent......
ETDT Pvalue=0.86, X^{2}(7df)=3.3 in DSMIV inattentive, ETDT Pvalue=0.12, X^{2}(6df)=10.0 in DSMIV combined, ETDT Pvalue=0.60, X^{2}(5df)=3.7 in DSMIV hyperactive/impulsive, ETDT Pvalue=0.81, X^{2}(7df)=3.8 in DSMIV any ADHD; allelewise Pvalue=0.41, corrected Pvalue=0.93 for Allele 2, allelewise Pvalue=1.00, corrected Pvalue=1.00 for Allele 3, allelewise Pvalue=0.58, corrected Pvalue=0.99 for Allele 4 and Allele 7, allelewise Pvalue=0.21, corrected Pvalue=0.68 for Allele 8 in DSMIV any ADHD; allelewise Pvalue=0.29, corrected Pvalue=0.81 for Allele 2, allelewise Pvalue=0.29, corrected Pvalue=0.82 for Allele 3, allelewise Pvalue=0.47, corrected Pvalue=0.96 for Allele 4, allelewise Pvalue=0.55, corrected Pvalue=0.98 for Allele 7, allelewise Pvalue=1.00, corrected Pvalue=1.00 for Allele 8 in DSMIV inattentive; allelewise Pvalue=0.82, corrected Pvalue=1.00 for Allele 2, allelewise Pvalue=0.10, corrected Pvalue=0.33 for Allele 3, allelewise Pvalue=0.89, corrected Pvalue=1.00 for Allele 4, allelewise Pvalue=1.00, corrected Pvalue=1.00 for Allele 7 in DSMIV combined; allelewise Pvalue=0.44, corrected Pvalue=0.68 for Allele 4, allelewise Pvalue=0.53, corrected Pvalue=0.77 for Allele 7 in DSMIV hyperactive/impulsive
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there was no evidence for biased transmission of any allele ......
there was no evidence for biased transmission of any allele for either polymorphism for the DSMIVdefined ADHD subtypes
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Nonsignificant

Mill J, 2001 

7R 
allelic TDT Pvalue=0.01, X^{2}=6.17, OR=1.73 in the......
allelic TDT Pvalue=0.01, X^{2}=6.17, OR=1.73 in the casecontrol analysis; TDT X^{2}=0.69 in the familybased analysis
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there was evidence of association in the casecontrol sample......
there was evidence of association in the casecontrol sample, but no evidence of linkage in the familybased UK sample
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Significant

Spencer, T. J., 2012 

7R 
Pvalue=NS, X^{2}=0.03
Pvalue=NS, X^{2}=0.03

the gene frequencies of each of the gene polymorphisms asses......
the gene frequencies of each of the gene polymorphisms assessed did not differ between the ADHD and control groups.
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Nonsignificant

Oades RD, 2008 


Pvalue= 0.014 for impulsive aggressive behavior
Pvalue= 0.014 for impulsive aggressive behavior

nominally significant association
nominally significant association

Significant

Lowe N, 2004 (a) 

7 repeat 
TDT Pvalue=0.198, OR=1.35, 95% CI=0.882.07
TDT Pvalue=0.198, OR=1.35, 95% CI=0.882.07

not statistically significant
not statistically significant

Nonsignificant

Roman T, 2001 

7R 
allelic HRR Pvalue=0.54, X^{2}=0.37 in the total sa......
allelic HRR Pvalue=0.54, X^{2}=0.37 in the total sample, allelic HRR Pvalue=1, X^{2}=0 in the combined type for 7R; chisquare between probands and controls =11.55, Pvalue=0.03, chisquare between parents and controls=12.17, Pvalue=0.03; Pvalue=0.55, X^{2}=0.36 for other allele
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no preferential transmission for either the 7repeat allele ......
no preferential transmission for either the 7repeat allele or other alleles was observed, but an excess of the 7repeat allele was observed when both ADHD probands and their parents were compared with an ethnically matched control sample
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Significant

Gizer IR, 2009 


Metaanalysis model: Random: OR=1.33, 95% CI=1.151.54, Pva......
Metaanalysis model: Random: OR=1.33, 95% CI=1.151.54, Pvalue=0.00007; Qstatistic: Pvalue=0.0006, I^{2}=54
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significant but modest association
significant but modest association

Significant

Holmes J, 2002 

7R 
Onesided binomial Pvalue=0.05 for 7 allele; chisquare for......
Onesided binomial Pvalue=0.05 for 7 allele; chisquare for allelewise TDT=13.63, 4df, Pvalue=0.009; adjusted Pvalue using Monte Carlo methods=0.02
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the results suggested an association between the DRD4 7 repe......
the results suggested an association between the DRD4 7 repeat allele and ADHD
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Significant

Kirley A, 2004 

7R 
allelic TDT Pvalue=0.198, X^{2}=1.94 in all proband......
allelic TDT Pvalue=0.198, X^{2}=1.94 in all probands, TDT Pvalue=0.098, X^{2}=3.19 in combined subtype
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there was no association of the DRD4 7repeat allele in all ......
there was no association of the DRD4 7repeat allele in all probands and combined subtype
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Nonsignificant

Niederhofer H, 2008 

7R 
HRR Pvalue=0.88, OR=0.93; allelic TDT X^{2}=0.04, O......
HRR Pvalue=0.88, OR=0.93; allelic TDT X^{2}=0.04, OR=0.92 in 36 trios. HRR Pvalue=1.0, OD=1.01; allelic X^{2}=0.04, OD=0.94 in 36 trios and 13 duos
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none of the alleles was significantly associated with ADHD n......
none of the alleles was significantly associated with ADHD neither by HRR nor TDT; a nonsignificant result was obtained by both HRR and TDT for the risk allele (7R)
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Nonsignificant

Johansson S, 2008 


Overall Pvalue=0.31; allelic Pvalue=0.27, OR=0.90
Overall Pvalue=0.31; allelic Pvalue=0.27, OR=0.90

showed no association
showed no association

Nonsignificant

Manor I, 2002 (a) 
28 repeat 
short repeat 
TDT Pvalue=0.05 for 76 families, TDT Pvalue=0.0025 for com......
TDT Pvalue=0.05 for 76 families, TDT Pvalue=0.0025 for combined Petak Tikvah sample, TDT Pvalue=0.006 for combined all 178 familes; casecontrol analysis Pearson Pvalue=0.032 (1 df)
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preferential transmission were observed; small but significa......
preferential transmission were observed; small but significant excess of the short DRD4 repeat in the ADHD probands compared to the control subjects was observed
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Significant

Langley K, 2009 


Casecontrol analysis: Pvalue=0.001, OR=1.86 (95%CI=1.302.......
Casecontrol analysis: Pvalue=0.001, OR=1.86 (95%CI=1.302.65) for baseline ADHD; Pvalue=0.0001, OR=2.12 (95%CI=1.453.11) for persistent ADHD.
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significant association between the DRD4 48 bp VNTR 7repeat......
significant association between the DRD4 48 bp VNTR 7repeat allele and 'persistent ADHD'.
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Significant

Leung PW, 2005 
2R/Non2R 

allelic chisquare Pvalue=0.015, X^{2}(1df)=5.90
allelic chisquare Pvalue=0.015, X^{2}(1df)=5.90

a significant increase in the frequency of the 2R allele in ......
a significant increase in the frequency of the 2R allele in the Han Chinese ADHD probands
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Significant

Johnson KA, 2008 


X^{2}(1)=3.739, Pvalue=0.040
X^{2}(1)=3.739, Pvalue=0.040

significant association between possession of the 7repeat a......
significant association between possession of the 7repeat allele and diagnosis
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Significant

Kim YS, 2005 

7R 
allelic TDT Pvalue=0.67; X^{2}=0.14 for 2R; X^{2......
}
allelic TDT Pvalue=0.67; X^{2}=0.14 for 2R; X^{2}=2 for 3R; X^{2}=2 for 3R; X^{2}=0.78 for 4R; X^{2}=0 for 4.5R; X^{2}=0.06 for 5R; X^{2}=0 for 6R; X^{2}=1 for 7R
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did not show preferential transmission of any allele
did not show preferential transmission of any allele

Nonsignificant

Ilott NE, 2010 


QTDT AT Pvalue=0.19, X^{2}=4.74, df=3, QTDT AW Pva......
QTDT AT Pvalue=0.19, X^{2}=4.74, df=3, QTDT AW Pvalue=0.35, X^{2}=3.26, df=3 at age 2; QTDT AT Pvalue=0.05, X^{2}=7.82, df=3, QTDT AW Pvalue=0.03, X^{2}=8.69, df=3 at age 3
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modest, nominally significant associations in the AT and AW ......
modest, nominally significant associations in the AT and AW tests at age 3
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Significant

Kirley A, 2002 

7 repeat 
HHRR: Pvalue=0.58 (RR=1.07, OR=1.15); TDT: Pvalue=0.677 (O......
HHRR: Pvalue=0.58 (RR=1.07, OR=1.15); TDT: Pvalue=0.677 (OR=1.17); TDT by presence of family history: Pvalue=0.441 (OR[95%CI]=2.2[0.4710.35]); TDT of Paternal and Maternal transmissions: Pvalue=0.207 (OR[95%CI]=0.44[0.121.57])
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no significant differences between transmitted and nontrans......
no significant differences between transmitted and nontransmitted alleles
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Nonsignificant

Brookes KJ, 2005 (a) 


allelic TDT Pvalue=0.55; HHRR Pvalue=0.55
allelic TDT Pvalue=0.55; HHRR Pvalue=0.55

global and allelespecific tests of association were nonsig......
global and allelespecific tests of association were nonsignificant
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Nonsignificant

Smith TF, 2010 


Comprehensive MetaAnalysis Pvalue=0.00005, OR=1.33
Comprehensive MetaAnalysis Pvalue=0.00005, OR=1.33

consistent with previous metaanalytic work, the DRD4 7R all......
consistent with previous metaanalytic work, the DRD4 7R allele was associated with AD/HD across studies
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Significant

Maher BS, 2002 


Pvalue=1.57E5, pooled OR=1.41; test of homogeneity Pvalue......
Pvalue=1.57E5, pooled OR=1.41; test of homogeneity Pvalue=0.40, Q=12.59, df=12
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positive association was demostrated with ADHD in the metaa......
positive association was demostrated with ADHD in the metaanalysis
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Significant

Carrasco X, 2006 


Fisher¡¯s exact test Pvalue=0.5621
Fisher¡¯s exact test Pvalue=0.5621

not significantly different from unaffected siblings
not significantly different from unaffected siblings

Nonsignificant

Nikolaidis A, 2010 


Comprehensive Metaanalysis Pvalue=0.0001, OR=1.64 in the C......
Comprehensive Metaanalysis Pvalue=0.0001, OR=1.64 in the Caucasian group; Comprehensive Metaanalysis Pvalue=0.014, OR=0.72 in the Middle Eastern group; Comprehensive Metaanalysis Pvalue=0.001, OR=2.41 in The South American group; Comprehensive Metaanalysis Pvalue=0.49, OR=1.65 in the Asian group
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the Caucasian group showed a positive relationship; the Midd......
the Caucasian group showed a positive relationship; the Middle Eastern group showed a negative relationship; the South American group also demonstrated a positive relationship and the Asian group demonstrated a positive but insignificant relationship
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Significant

Bhaduri N, 2006 (a) 
2 and 4 repeats/6 and 7 repeats 

HHRR Pvalue=0.0301, X^{2}=4.70, RR=1.81; TDT Pvalu......
HHRR Pvalue=0.0301, X^{2}=4.70, RR=1.81; TDT Pvalue=0.0588, X^{2}=3.57
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HHRR analysis showed a significant association; TDT analysis......
HHRR analysis showed a significant association; TDT analysis revealed a positive trend towards association
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Significant

Todd RD, 2005 
4R/7R 

data not shown in the publication
data not shown in the publication

no significant association was found with DSMIV defined ADH......
no significant association was found with DSMIV defined ADHD or ADHD subtypes
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Nonsignificant
