{{Genotype
| rsid = 1800795
| allele1 = C
| allele2 = C
|summary=less IL6; certain risks, see details
}}
[[rs1800795]] is a SNP in the promoter of the interleukin-6 [[IL6]] gene, affecting the levels made of this important [[cytokine]]. The (C;C) genotype is found almost exclusively in the caucasian populations. It was first described in 1998, when it was shown that the [[rs1800795]](C) allele produces less IL6 than the (G) allele, which supported the hypothesis that a protective genotype against systemic onset juvenile [[rheumatoid arthritis]] would be [[rs1800795]](C;C), and indeed, few juvenile RA patients had that genotype.[PMID 9769329]

The [rs1800795]](C) allele, generally associated with lower levels of IL6, has been associated with increased risk in these studies:

* [[rs1800795]] (C;C) and (C;G) Caucasians who are excessively heavy (body mass index ~33 +/- 5kg/m2) are at increased risk (odds ratio 5.2, p=0.003) for developing obesity-related metabolic disorders such as [[hypertension]], atherogenic dyslipidemia, and insulin resistance.[PMID 17998015]

* Among 571 patients with [[type-2 diabetes]], the [[rs1800795]](C) allele is correlated with higher body mass index, but it showed no correlation among non-diabetics.[PMID 15172007]

* A study of 238 Caucasians with [[type-2 diabetes]] concluded that [[rs1800795](C) carriers have an insulin resistance "IL-6-sensitive" phenotype and perhaps strategies to manage insulin resistance should be different between (C) carriers vs. (G;G) patients.[PMID 16140413]

* In patients with end-stage renal disease (ESRD) being treated by hemodialysis, [[rs1800795]](C) allele carriers had higher diastolic blood pressure (p=0.008) and a higher left ventricular mass index (p=0.026) than (G;G) homozygotes. Among diabetic patients in dialysis, the prevalence of left ventricular hypertrophy in (C) allele carriers was 87.5% vs. 36.3% among (G;G) genotypes (p= 0.02).[PMID 12846758]

* Among recipient of a kidney transplant, [[rs1800795]](C) allele carriers had worse three-year graft survival (71/104 = 68.3%; p=0.0059) with a 3.7-fold increased relative risk of graft loss compared to [[rs1800795]](G;G) genotypes (48/54 = 88.9%). The authors suggest that determining the [[rs1800795]] genotype may offer a new method for identifying patients at increased risk of allograft loss.[PMID 12371985]

* Among [[prostate cancer]] patients, the [[rs1800795]](C) allele is associated with more aggressive cancer and higher prostate-specific antigen levels compared to [[rs1800795]](G;G) homozygotes.[PMID 16006970]

* Although the [[rs1800795]](C) allele was not associated with a higher frequency of heart attacks, it did have an association with inflammation and infarcts detectable only by MRI, suggesting that [[rs1800795]](C) may chronically predispose an individual to develop atherosclerosis.[PMID 12482836]

* The combination of carrying at least one [[rs1800795]](C) and one [[rs1205]](T), a SNP in the C-reactive protein gene, led to higher risk of a [[stroke]] after cardiac surgery (odds ratio 3.3, CI: 1.4-8.1, p=0.0023) compared to individuals who were [[rs1800795]](G;G) and [[rs1205]](C;C).[PMID 16051899]

* The [[rs1800795]](C) allele was associated with higher postoperative IL6 levels and a less favorable clinical outcome following coronary revascularization surgery.[PMID 16183563]

* The [[rs1800795]](C;C) genotype was significantly higher in the group of 122 adult [[periodontitis]] patients than in controls (odds ratio 1.896, CI: 1.1-3.2, p=0.0283).[PMID 17209781]

* The degree of [[periodontitis]] was more severe in [[rs1800795]](C) carriers than (G) carriers.[PMID 17286759]

* The [[rs1800795]](C) allele was over-represented in patients with [[Alzheimer's disease]] compared to controls and the (C;C) genotype was associated with higher risk in women.[PMID 12928051]