Table 1.

Summary of genetic variants found in early seminal studies.

	Ancestry	Samples	Study type	Genetic variants	OR, P values	Functions
Sigurdsson et al., 2005 [21]	Swedish, Finnish	589 cases 377 controls	FB and CC association	rs2004640	OR = 1.59   P = 7.1 × 10−7	Altered exon 1 spicing
Graham et al., 2006 [22]*	Argentina, Spain, Sweden, USA	1661 cases 2508 controls	CC association	rs2004640	OR = 1.45 P = 4.4 × 10−16	Altered exon 1 splicing
		555 trio pedigrees,		Risk haplotype	OR = 1.78 P = 1.4 × 10−19	Altered exon 1 splicing, exon 6 in, short poly-A
Graham et al., 2007 [23]**	USA, UK, Sweden	2188 cases	FB and CC association	Protective haplotype 1	OR = 0.76 P = 5.0 × 10−8	Nonaltered exon 1 splicing, exon 6 in, long poly-A
		3596 controls		Protective haplotype 2	OR = 0.76 P = 2.8 × 10−5	Nonaltered exon 1 splicing, exon 6 del, short poly-A
Sigurdsson et al., 2008 [28]***	Sweden	485 cases 563 controls	CC association	CGGGG/−	OR = 1.69 P = 4.6 × 10−9	Promoter indel
				rs10488631	OR = 2.07 P = 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.