. 2013 Jan 22;3:tre-03-105-1843-1. doi: 10.7916/D8Q23Z0Z

Table 1. Association Study Cohort Sizes in Essential Tremor (ET) Genetics Research.

Study	ET n	Control n	ET Cohort Source	Overall Result
ETM1
HS1-BP3 828C→G variant	49	92	United States	Negative
Shatunov et al, 2005⁶³	49	92	United States	Negative
HS1-BP3 828C→G variant	73	304	United States	Positive
Higgins et al, 2006⁶¹	73	304	United States	Note initial 2005 report from same group with G variant in ET cases in 2 of 21 US ET families, not ET or unaffecteds in the other families, and not 150 US controls or 73 ET Singaporean cases
HS1-BP3 828C→G variant	222	132	United States	Negative
Deng et al, 2005⁶²	222	132	United States	Negative
ETM2
ETM2 sequence variants	30	30	Korean	Positive
Kim et al, 2005³⁷	30	30	Korean	Positive
ETM2 polymorphisms	61	68	Czech	Negative
Zahorakova et al, 2010³⁸	61	68	Czech	Negative
DRD3 312A→G variant	104	116	Latvian	Negative
Inashkina et al, 2008³⁹	104	116	Latvian	Negative
DRD3 312A→G variant	116	158	Italian	Negative
Vitale et al, 2008⁷⁰	116	158	Italian	Negative
DRD3 312A→G variant	163	192	Singaporean	Negative
Tan et al, 2007⁶⁸	163	192	Singaporean	Negative
DRD3 312A→G variant	201	282	Spanish	Positive
Garcia-Martin et al, 2009⁶⁶	201	282	Spanish	Positive
DRD3 312A→G variant	276	184	United States	Positive
Jeanneteau et al, 2006⁶⁵	30	50	French	Positive
DRD3 312A→G variant	299	528	German, Danish, French	Negative
Lorenz et al, 2009⁶⁹	299	528	German, Danish, French	Negative
DRD3 312A→G variant	433	272	United States	Negative
Blair et al, 2008⁶⁷	433	272	United States	Negative
LINGO genes
LINGO1 rs9652490 and rs11856808	109	430	Chinese Han	Negative
Zuo et al, 2010⁵⁴	109	430	Chinese Han	Negative
LINGO1 rs9652490	117	160	Chinese	Negative
Wu et al, 2011⁵⁷	117	160	Chinese	Note combining with Tan et al⁵³ plus unpublished data into 307 ET and 804 control, meta-analysis positive
LINGO1 rs9652490	141	130	Latvian	Positive
Radovica et al, 2012⁵²	141	130	Latvian	9 other SNPs including rs11856808 negative
LINGO4 variants	150	300	Chinese Han	Negative
Liang et al, 2012⁵⁹	150	300	Chinese Han	Negative
LINGO1 rs9652490	190	733	Singaporean	Positive
Tan et al, 2009⁵³	190	733	Singaporean	Positive
LINGO1 rs9652490 and rs11856808	226	1117	Spanish	Negative
Lorenzo-Betancor et al, 2011⁵⁵	226	1117	Spanish	Negative
LINGO1 SNPs	257	265	United States	Positive for rs9652490 and others
Clark et al, 2010⁵¹				Negative for rs11856808 and others out of 15 SNPs total
Clark et al, 2010⁵¹				Note meta-analysis combining 3 or 4 published cohorts⁴⁶^,⁵⁰^,⁵¹^,⁵³ also positive
LINGO1 rs9652490 and rs11856808	259	479	French Canadian	Negative
Bourassa et al, 2011⁵⁶	259	479	French Canadian	Negative
LINGO2 variants	327	499	Chinese, Singaporean	Positive for rs7033345 and rs10812774 of 8 variants
Wu et al, 2011⁵⁸	327	499	Chinese, Singaporean	Positive for rs7033345 and rs10812774 of 8 variants
LINGO1 SNPs	332	574	German, French	Positive for rs9652490 and 1 other
Thier et al, 2010⁴⁸	332	574	German, French	Negative for rs11856808 and others out of 10 SNPs total
LINGO1 rs9652490	356	428	North American	Positive
Vilarino-Guell et al, 2010⁵⁰	356	428	North American	Positive
GWAS	452	14,394	Icelandic	Positive for LINGO1 rs9652490 and rs11856808 in initial cohort; rs9652490 only in confirmatory cohorts
Stefansson et al, 2009⁴⁶	281	1188	Austrian, German, United States
LINGO1 and LINGO2 variants	1247	642	North American	Positive for LINGO1 rs9652490 and 4 others of 16 total, and LINGO2 rs1412229 alone of 21.
Vilarino-Guell et al, 2010⁴⁹	1247	642	North American
*SNCA*
REP1 length	46	100	United States	Positive
Tan et al, 2000⁷⁵	46	100	United States	Positive
SNCA variants	106	90	Italian	Negative
Pigullo et al, 2003⁹⁰	106	90	Italian	Negative
SNCA variants	647	1285	North American	Negative
Ross et al, 2011⁹¹	647	1285	North American	Negative
Other variants
GABAAR subunit genes variants	200	250	Spanish	Negative
Garcia-Martin et al, 2011⁹⁴^,⁹⁵	200	250	Spanish	Negative
GABAAR subunits and GABA transporter genes variants	503	818	German, Dutch	Negative
Thier et al, 2011⁹³	503	818	German, Dutch	Negative
HNMT rs11558538	204	295	Spanish	Positive
Ledesma et al, 2008⁹⁶	204	295	Spanish	Positive
HNMT rs11558538	338	409	North American	Negative
Keeling et al, 2010⁹⁷	338	409	North American	Negative

Studies are grouped under genetic categories, and listed by first author and year of publication. Within hypothesis groups, studies are ordered by ET n. If the study combined cohorts in one analysis then the full ET n is used. If the same study used different cohorts in different analyses, the larger ET n is listed first. ET cohort source is geographical; some papers have further details on ethnicity. North American = United States and Canada. Overall result considers the main thrust of the study, with a few further notations; see text for comments on age of onset influences, and cited references for full study results details including specific genetic variants tested, haplotype analyses, methods.

Abbreviations: DRD3, dopamine D3 receptor gene; ET, essential tremor; ETM, Hereditary Essential Tremor, Online Mendelian Inheritance of Man (OMIM) locus designation; GABA, gamma-aminobutyric acid; GABAAR, gamma-aminobutyric acid A receptor; HNMT, histamine N-methyltransferase gene; HS1-BP3, HS1 binding protein 3 gene; LINGO, leucine-rich repeat- and Ig domain-containing Nogo receptor-interacting protein; numbered italicized LINGOs are genes encoding LINGO proteins; REP1, mixed dinucleotide repeat sequence in the SNCA promoter region; SNCA, gene encoding α-synuclein; SNPs, single nucleotide polymorphisms; US, United States.