{{Rsnum
|rsid=3135391
|Gene=HLA-DRA
|Chromosome=6
|position=32443210
|Orientation=minus
|GMAF=0.06612
|Gene_s=HLA-DRA,LOC100289398
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 66.4 | 29.2 | 4.4
| HCB | 96.4 | 3.6 | 0.0
| JPT | 100.0 | 0.0 | 0.0
| YRI | 93.2 | 6.8 | 0.0
| ASW | 87.7 | 12.3 | 0.0
| CHB | 96.4 | 3.6 | 0.0
| CHD | 99.1 | 0.9 | 0.0
| GIH | 96.0 | 4.0 | 0.0
| LWK | 93.6 | 6.4 | 0.0
| MEX | 87.9 | 12.1 | 0.0
| MKK | 95.5 | 4.5 | 0.0
| TSI | 84.3 | 14.7 | 1.0
| HapMapRevision=28
}}[[rs3135391]] is highly correlated with the [[HLA-DRB1]]*1501 allele. The risk allele (T),  is associated with a 3 to 6 fold higher risk for developing [[multiple sclerosis]], and is the most significantly associated risk factor for MS. [[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892470/ PMC2892470]]
In one study, for example, the odds ratio was reported to be 3.04 (p < 1 x 10e-78).[PMID 20593013]

The HLA-DRB1*1501 allele has also been associated with other [[autoimmune disease]]s, such as [[systemic lupus erythematosis]] ([[SLE]]) ([http://www.nature.com/ng/journal/v38/n10/fig_tab/ng1885_T1.html see]) and possibly [[narcolepsy]]. The HLA-DRB1*1501 allele is fairly common; for example, it occurs in 15-30% of individuals of Northern European ancestry. [[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892470/ PMC2892470]]

An interesting series of correlations have been woven together to suggest that a possible way to lower the risk of [[rs3135388]](T) carriers developing multiple sclerosis would be to ensure sufficient [[vitamin D]] production, presumably through sunlight exposure, during as yet unknown critical periods in development. {{doi|10.1371/journal.pgen.1000369}}

{{PMID Auto
|PMID=19143815
|Title=MHC fine mapping of human type 1 diabetes using the T1DGC data.
|OA=1
}}

{{PMID Auto
|PMID=19846760
|Title=Mapping of multiple susceptibility variants within the MHC region for 7 immune-mediated diseases.
|OA=1
}}

[[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892470/ PMC2892470]] A major histocompatibility Class I locus contributes to multiple sclerosis susceptibility independently from HLA-DRB1*15:01.

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
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{{on chip | FTDNA2}}
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{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}