Table 1.

Selection of SNPs showing:their allele frequencies in different ethnic populations, reference to the polymorphism report and comment on possible associations with cardiac adverse events

SNP	Allele frequency (%)	Population	Reference	Location	Comments
R176W	<1	White American	Ackerman et al. (2003) N-terminus	N-terminus	Also found in internal screening of 9 terodiline induced TdP cases (Ford et al. (2000). Found in LQTS patients (Laitinen et al., 2000)
R181Q	<1	Black American	Ackerman et al. (2003)	N-terminus
Del187-189	<1	Black American	Ackerman et al. (2003) N-terminus P347S	N-terminus
P347S	<1 2 <1	White American Caucasian Caucasian	Ackerman et al. (2003),Splawski et al. (2000) N-terminus	N-terminus	Identified in subject with cisapride/clarithromycin induced QT prolongation (Paulussen et al., 2004)
K897T	16.5 4.2 4 3	White American Black American Asian Hispanic	Ackerman et al. (2003) C-terminus	C-terminus	Associated with increased risk of cardiac mortality (Linna et al. (2006). Proposed to modify clinical expression of A1116V SNP (Crotti et al., 2005)
A915V	2.2	Asian	Ackerman et al. (2003) C-terminus P917L	C-terminus
P917L	<1 <1	White American Caucasian	Ackerman et al. (2003) C-terminus	C-terminus	Identified in LQTS population (Splawski et al., 2000)
R1047L	3 1.8 <1	Caucasian White American Black American	Ackerman et al. (2003) AstraZeneca, unpublished observation	C-terminus	Association with Dofetilide induced TdP described (Sun et al., 2004)
A1116V	<1	Caucasian	AstraZeneca, unpublished observation	C-terminus	Also identified in case study of cardiac arrest caused by ventricular fibrillation (Crotti et al., 2005)

LQTS, long QT syndrome; SNP, single nucleotide polymorphism; TdP, Torsades de Pointes; WT, wild-type.