Table 1: Summary of genetic variants found in early seminal studies.

AncestrySamplesStudy typeGenetic variantsOR,
values
Functions

Sigurdsson et al., 2005 [21]Swedish,
Finnish
589 cases
377 controls
FB and CC associationrs2004640 OR = 1.59  
= 7.1 10−7
Altered exon 1 spicing

Graham et al., 2006 [22]*Argentina,
Spain,
Sweden,
USA
1661 cases
2508 controls
CC associationrs2004640OR = 1.45
= 4.4 10−16
Altered exon 1 splicing

555 trio
pedigrees,
Risk haplotypeOR = 1.78
= 1.4 10−19
Altered exon 1 splicing, exon 6 in, short poly-A
Graham et al., 2007 [23]**USA, UK,
Sweden
2188 casesFB and CC associationProtective haplotype 1OR = 0.76
= 5.0 10−8
Nonaltered exon 1 splicing, exon 6 in, long poly-A
3596 controlsProtective haplotype 2OR = 0.76
= 2.8 10−5
Nonaltered exon 1 splicing, exon 6 del, short poly-A

Sigurdsson et al., 2008 [28]*** Sweden485 cases
563 controls
CC associationCGGGG/−OR = 1.69
= 4.6 10−9
Promoter indel
rs10488631OR = 2.07
= 9.4 10−10
Altered exon 1 splicing, exon 6 in, short poly-A

*The populations were mostly of European ancestry.
**Only the haplotype analysis is shown here. SNP rs2070197 was found to be a proxy for the risk haplotype.
***SNP rs10488631 is in high LD with rs2070197 and was used as a proxy for the risk haplotype. OR and P values are obtained from nonconditional analysis.
FB: family based, CC: case-control, OR: odds ratio, P: P value, poly-A: poly-adenylation, in: insertion, del: deletion, indel: insertion/deletion, LD: linkage disequilibrium.