Norwegian Sami differs significantly from other Norwegians according to their HLA profile.

This study reports extensive genomic data for both human leukocyte antigen (HLA) class I and II loci in Norwegian Sami, a native population living in the northwest of Europe. The Sami have a distinct culture and their own languages, which belong to the Uralic linguistic family. Norwegian Sami (n = 200) were typed at the DNA level for the HLA-A, -C, -B, -DRB1 and -DQB1 loci, and compared with a non-Sami Norwegian population (n = 576). The two populations exhibited some common genetic features but also differed significantly at all HLA loci. The most significantly deviating allele frequencies were an increase of HLA-A*03, -B*27, -DRB1*08 and -DQB1*04 and a decrease of HLA-A*01, C*01, -DRB1*04 and -DQB1*02 among Sami compared with non-Sami Norwegians. The Sami showed no deviation from Hardy-Weinberg equilibrium. The hypothesis of selective neutrality was rejected at all loci except for the A- and C- loci for the Sami. HLA haplotype frequencies also differed between the two populations. The most common extended HLA haplotypes were A*02-B*27-C*01-DR*08-DQB1*04 in the Sami and A*01-B*08-C*07-DR*03-DQB1*02 in the other Norwegians. Genetic distance analyses indicated that the Norwegian Sami were highly differentiated from other Europeans and were most closely related to Finns whose language also belongs to the Uralic linguistic family. In conclusion, the Norwegian Sami and the non-Sami Norwegians were significantly different at all HLA loci. Our results can be explained by the fact that the two populations have different origins and that the Sami population has remained smaller and more isolated than its neighbors.

Low frequency of the disease-associated DRB1*15-DQB1*06 haplotype may contribute to the low prevalence of multiple sclerosis in Sami.

This study confirms a low frequency of multiple sclerosis (MS) among Sami. Only 12 Sami with a diagnosis of MS were identified in the Norwegian Sami population, which represents a significantly lower prevalence of MS in Sami (30/10(5)) compared with other Norwegians (73-164/10(5)). The clinical characteristics as well as the results of human leukocyte antigen (HLA)-DRB1 and -DQB1 typing of the Sami MS patients are reported, showing that three (27%) of the Sami MS patients carried the MS-associated HLA-DRB1*15-DQB1*06 haplotype. Interestingly, the DRB1*15-DQB1*06 haplotype had a significantly reduced frequency among Sami controls (0.086) compared with non-Sami Norwegian controls (0.163) (P(corrected) = 0.015). The low frequency of the disease-associated DRB1*15-DQB1*06 haplotype in the Sami population may contribute to the low prevalence of MS in Sami, in addition to other yet unidentified genetic and environmental factors.

Ethnic variations of IL-10 polymorphisms in a Sami and Norwegian population.

Interleukin-10 (IL-10) production is genetically determined and influenced by different polymorphisms in the promoter region of IL-10. These polymorphisms may contribute to the risk and clinical outcome of various infectious and immunological-related diseases. The Samis are the aboriginal inhabitants of Norway and Fennoscandinavia and are ethnically different from the Norwegians. Different distribution of various immune-related diseases among the Samis compared with Norwegians have been reported. This is the first study to evaluate the distribution of IL-10 polymorphisms in the Sami population. Two hundred healthy Samis were genotyped for polymorphisms in the promoter region of IL-10 at region -1082 (G/A), -819 (T/C) and -592 (A/C). The allele frequencies, genotypes and haplotypes were compared with 187 healthy Norwegians. A significantly higher number of the Samis than the Norwegians had the ATA/ATA genotype, whereas the Norwegians displayed a higher frequency of the GCC/GCC genotype (P=0.0057). There was a significant difference in haplotypes in the two populations with a P=0.0024. These findings may be important for the distribution and clinical outcome of various infectious and immune-related disorders in the two populations.

Detection of one single mutation predicts thiopurine S-methyltransferase activity in a population of Saami in northern Norway.

Thiopurine S-methyltransferase (TPMT) activity exhibits genetic polymorphism. The purpose of this investigation was to identify TPMT mutant alleles in the Saami population as a basis of developing genotyping tests for prediction of TPMT activity. The most predominant allele in Saamis (n = 194) was the TPMT*3C allele (A719G mutation) representing 92% of the mutant alleles, with an estimated allelic frequency of 3.3%. The most frequent allele in Caucasians (n = 66) living in the same geographic area was the TPMT*3A (A719G and G460A mutations) representing 91% of the mutant alleles, with an estimated allelic frequency of 3.4%. A test for one mutation, A719G, may prospectively identify more than 90% of the Saami individuals who require reduction in thiopurine dose to avoid hematopoietic toxicity. In a Norwegian population, comprising both the major Caucasian population and a minor Saami population, the same genotyping tests (eg, tests for the A719G and G460A mutations) may be used.

Dietary and nutrient intake of a Sami population living in traditional reindeer herding areas in north Norway: comparisons with a group of Norwegians.

The Samis are an ethnic minority living in the Northern region of Norway, Sweden, Finland and Russia. Traditionally the Samis made their living from reindeer herding with some fishing and agriculture. Earlier studies have shown that their diet consisted of large amounts of reindeer meat, some fish and wild berries with low intakes of other fruits, vegetables and dairy products. Due to the introduction of technical improvements like snowmobiles and terrain vehicles which makes moving with the herd less necessary, their lifestyle has changed. There is little documentation how this has affected their dietary habits. In this study, the dietary pattern and nutrient intake of a group of Samis (n = 75) living in traditional reindeer herding areas of North Norway were investigated and compared with that of a group of Norwegians (n = 65). Dietary information was obtained through an interview by a nutritionist using the dietary history method. The findings indicate that nutrient content of the Sami diet is adequate except for folic acid. Calcium and iron intake was slightly below recommended levels for Sami females. There seems to be some difference between the diet of the Samis and Norwegians. The Samis consume more meat, fat, table sugar and coffee and less fruits and vegetables. The dietary pattern of the Samis seems, however, to be changing toward a more typically Norwegian diet.

[Coronary heart diseases among Lapps and Norwegians in Finnmark]. / Koronar hjertesykdom hos samiskaettede og norskaettede i Finnmark.

The Finnmark Health Survey of 1987-88 showed that there was no significant difference in the prevalence of coronary heart disease between a Sámi population and a Norwegian population. Among men 40-59 years of age, a prevalence of myocardial infarction or angina pectoris or both, of 5.5%, was found both in Norwegians and in the predominantly Sámi population of Inner Finnmark. Among women, a prevalence of 3.1% and 3.3% was found among Norwegians and Sámis, respectively. The difference in results between males and females was less among Sámis than Norwegians, despite Sámi women having a lower risk factor level than Norwegian women. A clinical follow-up study done in 1992-93 showed no significant differences in serum lipid concentrations between the Sámi and the Norwegian population. Sámis had a lower familial occurrence of coronary heart disease than Norwegians. Waist to hip ratio was higher among Sámis than Norwegians.

Saami mitochondrial DNA reveals deep maternal lineage clusters.

The mitochondrial DNA of 62 Saami from the north of Norway was analyzed in the D loop hypervariable region I and II and sequences were compared to other gene pools. Two major (lineage 1 and 2) and two minor (lineage 3 and 4) maternal lineage clusters were found. Lineage 1 (56.9% of all hitherto analyzed Saami samples) contains a substantial number of branching haplotypes which are unknown in European gene pools. Lineage 2 (31.5%) and lineage 4 (3.6%) have few branching points and are present at a low rate throughout European gene pools. Lineage 3 (4.7%) has polymorphisms characteristic of circumpolar lineages.

Interethnic difference in thiopurine methyltransferase activity.

A number of metabolic pathways are subject to both genetic polymorphism and interethnic differences. A catabolic pathway of 6-mercaptopurine, red blood cell (RBC) thiopurine methyltransferase (TPMT) activity showed genetic polymorphism in Caucasians, but variation according to ethnicity has not been studied. We investigated if red blood cell thiopurine methyltransferase was subject to interethnic variation in a Saami (Lappish; n = 36) and a Caucasian population (n = 50). The Saami population sample had 29% higher thiopurine methyltransferase activity, 17.0 +/- 3.3 U/ml red blood cell compared with the Caucasian population sample, 13.1 +/- 2.9 U/ml red blood cell (p much less than 0.001). Probit plots and frequency distribution histograms supported bimodality consistent with genetic polymorphism in both study populations. Differences in chronic diseases, drug consumption, age, or gender could not explain the interethnic difference in red blood cell thiopurine methyltransferase activity. The higher red blood cell thiopurine methyltransferase activity in the Saami population group indicates that these subjects may require higher dosages of thiopurine drugs than Caucasians.

High serum selenium concentrations in reindeer breeding Lappish men.

This study investigated the relationship of serum selenium to its dietary sources in a group of Lappish men and a control population. Lappish men had higher serum selenium concentrations than non-Lappish men (1.79 vs 1.58 mumol/1; p = 0.003). Serum selenium correlated positively with consumption of reindeer meat, age and cholesterol. In linear regression models, however, being Lappish was the most significant predictor of high serum selenium. Lappish men ate more reindeer meat (p = 0.001) and less fish (p = 0.013) than men in the control group. Consumption of reindeer meat was also correlated with higher serum cholesterol levels. We conclude that high serum selenium concentrations in Lappish men may be important since low mortality from cancer is reported in this group.