{{Rsnum
|rsid=3923809
|Gene=BTBD9
|Chromosome=6
|position=38473194
|Orientation=plus
|GMAF=0.4031
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene_s=BTBD9
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 50.4 | 44.2 | 5.3
| HCB | 12.7 | 47.0 | 40.3
| JPT | 12.7 | 46.4 | 40.9
| YRI | 44.5 | 45.9 | 9.6
| ASW | 47.4 | 43.9 | 8.8
| CHB | 12.7 | 47.0 | 40.3
| CHD | 21.3 | 47.2 | 31.5
| GIH | 28.7 | 50.5 | 20.8
| LWK | 56.4 | 39.1 | 4.5
| MEX | 31.0 | 50.0 | 19.0
| MKK | 61.9 | 33.5 | 4.5
| TSI | 47.1 | 47.1 | 5.9
| HapMapRevision=28
}}This SNP, located in an intron of the [[BTBD9]] gene, has a variant that is seen somewhat more frequently in individuals with [[restless legs syndrome]]. The risk allele is [[rs3923809]](A); carriers of two such alleles, i.e. those with [[rs3923809(A;A)]] genotypes, are estimated to be 1.9 fold more likely to have [[restless legs syndrome]] than [[rs3923809(G;G)]] individuals. The authors of this study suggest that perhaps half of the cases of restless legs syndrome may involve the [[rs3923809]] risk genotypes. {{PMID|17634447}}

Consistent with this finding, another report about [[rs3923809]] links the (G) minor allele to a lower frequency of [[restless legs syndrome]] with an overall odds ratio of 0.57 (CI: 0.48-0.68). {{PMID|17637780}}

Note that 70-80% of all individuals in European populations carry one or two copies of the (A) major allele, yet [[restless legs syndrome]] is thought to affect less than 10% of all adults. Therefore, although an individual may be at higher risk based on their genotype, the genotype by itself certainly isn't able to predictably cause [[restless legs syndrome]].

The association between [[rs3923809]] and RLS has been replicated in three European populations, and shows the most consistent effect across populations of several SNPs studied.{{PMID|19279021|OA=1
}}

The results of a 2013 study of Korean patients suggest that the role of [[BTBD9]] in the pathogenesis of [[restless legs syndrome]] is more universal across populations than previously reported and more efforts should be focused on the role of epistasis in the genetic architecture of restless legs syndrome. A significant association was found for [[rs3923809]] and [[rs9296249]] in [[BTBD9]].  {{PMID|24293752}}

{{GWAS Summary
|SNP=rs3923809
|PubMedID=17634447
|Condition=Restless legs syndrome
|Gene=BTBD9
|Risk Allele=A
|pValue=1.00E-017
|OR=1.9
|95CI=1.50-2.20
}}

{{omim
|desc=RESTLESS LEGS SYNDROME, SUSCEPTIBILITY TO, 6
|id=611185
|rsnum=3923809
}}
{{PMID Auto
|PMID=19223043
|Title=Exploring the genetic link between RLS and [[ADHD]]
}}

{{PharmGKB
|RSID=rs3923809
|Name_s=
|Gene_s=BTBD9
|Feature=
|Evidence=PubMed ID:17634447; Web Resource:http://www.genome.gov/gwastudies/
|Annotation=GWAS Results: A genetic risk factor for periodic limb movements in sleep (Initial Sample Size: 306 cases, 15,664 controls; Replication Sample Size: 311 cases, 1,895 controls; Risk Allele: rs3923809-A).
|Drugs=
|Drug Classes=
|Diseases=Restless Legs Syndrome
|Curation Level=Non-Curated
|PharmGKB Accession ID=PA162356673
}}

{{PharmGKB
|RSID=rs3923809
|Name_s=
|Gene_s=BTBD9
|Feature=
|Evidence=PubMed ID:17634447
|Annotation=In a GWAS of Icelandic cases and controls, rs3923809 was found to be associated with Restless Legs Syndrome and periodic limb movements in sleep. This association was replicated in another Icelandic sample and in a U.S population.
|Drugs=
|Drug Classes=
|Diseases=Restless Legs Syndrome
|Curation Level=Curated
|PharmGKB Accession ID=PA162356144
}}

{{GET Evidence
|impact=pathogenic
|qualified_impact=Insufficiently evaluated pathogenic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs3923809
|overall_frequency_n=50
|overall_frequency_d=128
|overall_frequency=0.390625
|n_genomes=33
|n_genomes_annotated=0
|n_haplomes=48
|n_articles=1
|n_articles_annotated=0
|in_gwas=Y
|in_pharmgkb=Y
|autoscore=2
|webscore=N
}}

{{PMID|24293752}} Association of restless legs syndrome variants in Korean patients with restless legs syndrome.

{{PMID Auto
|PMID=23361623
|Title=The BTBD9 gene may be associated with antipsychotic-induced restless legs syndrome in schizophrenia
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}