Increased prevalence of systemic sclerosis in a native american tribe in oklahoma. Association with an amerindian HLA haplotype

Abstract

Objective. To investigate a high prevalence of systemic sclerosis (SSc; scleroderma) in a well-defined population of 21,255 Choctaw Indians residing in 8 southeastern Oklahoma counties who were "users" of Indian Health Services.Methods. A case-control study of 12 SSc cases and 48 matched non-SSc controls (4 per case) was conducted to investigate potential occupational, residential, and infectious exposures, as well as genetic factors which might predispose to SSc. HLA class I1 alleles were determined by DNA oligotyping, and class I and 111 alleles were defined serologically.Results. The prevalence of SSc in full-blooded Choctaws was at least 8/1,704, or 469/100,000 (95% confidence interval 195% CI] 203-930) over the 4-year interval 1990-1994 and was significantly higher than that among non-full-blooded Choctaws (6/19,551, or 31/100,000) (P = 0.00001, odds ratio [OR] = 15.4, 95% CI 4.9-49.8). The overall prevalence of SSc in Oklahoma Choctaws (66/100,000) also was significantly higher than that in other Native Americans in Oklahoma (9.5/100,000) (P = OR = 6.95, 95% CI Supported by granls from the Sclerodcrma Federation/ United Sclerodcrma Foundation, and the RGK Foundation.

Association of novel polymorphisms with the expression of SPARC in normal fibroblasts and with susceptibility to scleroderma

“…None of the patients or control subjects were known to be first-degree relatives. This population has the highest prevalence of SSc reported, and the clinical disease pattern is relatively homogeneous (20). In addition, in previous studies, we have reported a genetic association/linkage of the fibrillin 1 gene (FBNI) with SSc in this population (20,21).…”

Prevalence, incidence, survival, and disease characteristics of systemic sclerosis in a large US population

“…The highest prevalence of SSc has been reported in a Choctaw Native American group in Oklahoma (660 cases per million, based on 14 cases) (39). Genetic influences have been proposed to account for this increase but have not yet been definitively identified (39; for review, see ref.…”

Interstitial lung disease in South Africans with systemic sclerosis

“…It has an estimated worldwide prevalence between 50 and 300 per one million population. The incidence and prevalence varies geographically and amongst different ethnicities (1,3,16) . In a study carried out in South Africa at Chris…”

“…The non-HLA associated gene IRF8 has been linked to lcSSc and ACA (21) . Choctaw Native Americans have a unique HLA haplotype which is thought to confer SSc susceptibility (16) . These genetic associations may, with further elucidation, help to explain individual susceptibility to SSc, as well as help to explain the driving force behind associations between disease subtypes, laboratory features, and clinical outcomes, which are currently not clearly defined.…”

“…These autoantibodies vary with disease subtypes, outcomes, and the population involved, although there is overlap. The ATA is very common (71%) in the Choctaw Native Americans (16) , a population group with the highest rate of SSc worldwide. American…”