Transferrin C subtypes in different ethnic groups.
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Ethnicity↗
Biomedical subjects
C Sikström
Publications and source records attributed to C Sikström.
Transferrin C subtypes and spontaneous abortion.
The transferrin C subtypes were studied in relation to spontaneous abortion and a number of different genetic markers and traits. Among mothers with a history of spontaneous abortion an increased frequency of the C2 gene and especially of the C2 type was found. A correlation was found between the maternal C2 type and the placental alkaline phosphatase variant F, which previously has been shown to be associated with spontaneous abortion. The mechanism behind the intrauterine selection implied is unlikely to be immunological incompatibility between mother and fetus. No association was found with ABO and Rh blood groups, Hp and Gc serum groups, the pregnancy zone protein (PZ), red cell acid phosphatase types and birth weight.
Abortion, Habitual↗
Transferrin variants as markers of migrations and admixture between populations in the Baltic Sea region.
Transferrin (TF) types were examined by isoelectric focusing in an attempt to elucidate migrations and admixture between populations in the Baltic Sea region. A highly significant heterogeneity between populations was found with respect to TF*C subtypes as well as the rare TF variants B2, B0-1 and DCHI. With the exception for Estonia, increased frequencies of the TF*C3 allele were observed east of the Baltic Sea. The island of Gotland in the middle of the Baltic Sea also showed a high TF*C3 frequency indicating an eastern influence. The TF*DCHI allele, a marker of eastern (Finno-Ugric) influence, was found in Finland and Estonia and on the island of Gotland, but not in mainland Sweden and in the Baltic peoples (Latvians and Lithuanians). These results indicate the presence of a Finno-Ugric, most likely Estonian or Livonian, genetic influence in the Gotland population.
Alleles↗
New DNA polymorphisms define ethnically distinct haplotypes in the human transferrin receptor gene.
In a study of transferrin receptor (TFR) polymorphism in different ethnic groups using PCR and restriction cleavage we found a new Hin6I polymorphism in intron 7 and confirmed a tentative BanI polymorphism in exon 4 reported by Evans and Kemp [Gene 1997;199:123-131]. In all ethnic groups there was a complete and highly significant (p < 10(-10)) linkage disequilibrium where all BanI 1 alleles were linked to Hin6I 1 alleles. Furthermore in the European populations, but not in the Chinese, there was a close correlation between the three BanI-Hin6I haplotypes and the alleles of a previously described three-allelic RsaI polymorphism in the TFR gene studied by Southern blotting. There were distinct ethnic differences in TFR allele and haplotype frequencies. Thus the Saamis were significantly different from the other European ethnic groups, and the Lithuanians had a significantly increased frequency of the BanI 2-Hin6I 1 haplotype, suggesting that this marker may be informative in tracing prehistoric migrations and admixture by Baltic peoples. The new TFR polymorphisms and haplotypes may also be useful markers in studies of interactions with the transferrin and hemochromatosis genes, the genetic influence on body iron stores and disease associations.
Alleles↗
Transferrin C subtypes and myocardial infarction.
Transferrin C subtypes were studied in 124 patients who were survivors of myocardial infarction and population controls to test the hypothesis that the TFC2 type is associated with an increased risk for myocardial infarction. The TFC2 type showed, however, only a marginal increase among the patients (p = 0.038), whereas the TF*C3 allele (p = 0.0004) and the types carrying the TFC3 variant, TFC3-1 and C3-2, displayed a highly significant increase (p = 0.0002).
Female↗
Orosomucoid polymorphism in Finns, Swedes and Swedish Saamis.
Genetic polymorphism of orosomucoid (ORM) was studied by isoelectric focusing and immunoblotting in Finns, Swedes and Swedish Saamis. The ORM2 locus was found to be monomorphic in all three ethnic groups. In the Swedish sample the frequency of the ORM1*2 allele (0.414) was within the range found in other European populations, whereas Finns (0.282) and Saamis (0.210) showed significantly lower ORM1*2 frequencies. The extremely low ORM1*2 frequency in the Saamis further underlines the genetic uniqueness of this population. The ORM1*2 frequency in Saamis resembles those in Asiatic Mongoloid populations, but this is unlikely to reflect an Asiatic influence, since the accumulated knowledge on genetic markers in the Saamis show no unequivocal evidence for an Asiatic influence in this population.
Adult↗
Transferrin types, iron-binding capacity and body iron stores.
Increased body iron stores and transferrin (TF) variants have been found to be associated with adverse health effects believed to be caused by oxygen free radicals. Previous attempts to establish a relationship between TF types, serum TF concentrations and iron-binding have been inconclusive. We have studied serum iron, total iron-binding capacity (TIBC), TF saturation and serum ferritin in relation to genetic TF types in a population sample (691 females and 639 males) from northern Sweden in an attempt to elucidate whether individuals with TF variants associated with adverse somatic and reproductive effects (TFC2 and C3) have increased body iron stores. As expected there was a highly significant sex difference, males manifesting increased body iron stores viz. increased levels of serum iron, TF saturation and serum ferritin, and a lower TIBC. There was no consistent and statistically significant association between the TFC2 variant and the parameters that indicate iron binding and storage. Thus the associations between TFC2 and somatic and reproductive damage appear to be independent of iron binding and body iron stores. TIBC (and TF levels) showed significant differences between TF types in females (p = 0.0015) but not in males. In females the TFC3 variant was associated with a significantly lower (p = 0.002) TIBC value. This decreased TIBC value was, however, not accompanied by an increased ferritin value, thus there was no unequivocal evidence for an association between TFC3 and increased body iron stores.
Alleles↗
Serum complement (C3, BF, C4) types in Swedish Saamis.
Serum complement (C3, BF, C4) types were examined in Swedish Saamis (Lapps). In agreement with previous studies, a very low frequency of the C3*F allele (0.033) was found. Compared to Swedes and other Caucasian populations, Swedish Saamis showed a significantly increased frequency of the BFS, C4A4 and C4B2 variants, and a lower frequency of C4 deficiency. BFS, C4A4 and C4B2 show haplotype associations and thus the frequency of the S-A4-B2 complotype is significantly increased among the Saamis. Although the serum complement constitution of the Saamis shows some similarity with that of Asiatic Mongoloid populations it is unlikely to be due to Asiatic ethnic influence. The marked genetic deviations of the Saamis from all other populations has often been interpreted as a result of the founder effect and genetic drift. In this particular case, however, immunogenetic adaptation appears to be a plausible alternative explanation for the deviations in genetic complement factors.
Adaptation, Biological↗
Population studies in northern Sweden. XIX. The orosomucoid polymorphism.
Genetic polymorphism of orosomucoid (ORM1) was studied by isoelectric focusing in 3,817 conscripts and blood donors from the countries of Norrbotten and Västerbotten in northern Sweden. The individuals were distributed according to place of birth into 23 subpopulations. There was a significant heterogeneity between the 23 subpopulations with respect to the allele frequencies (p = 1 x 10(-8)). The ORM1*2 allele varied between 27 and 46%, and a clineal variation was observed with decreasing ORM1*2 allele frequencies in the northern direction. Significant correlations were found between the frequencies of the ORM1 alleles and previously studied Finnish and Saamish marker genes. The geographical variation of ORM1 alleles was in close agreement with the pattern expected from the known mixture of Finns, Saamis, and Swedes in northern Sweden and further underlines the impact of ethnic heterogeneity on the genetic differentiation of the north Swedish population.
Alleles↗
PstI restriction fragment length polymorphism of the human intestinal alkaline phosphatase gene.
Restriction fragment length polymorphisms have previously been found in the placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (GCAP) genes, but not in the closely related intestinal alkaline phosphatase (IAP) locus. We here report on a PstI restriction fragment length polymorphism in IAP found in Finns and Swedes but not in Saamis. A probable T-->G mutation in position 175 of intron 11 would create a new cleavage site for PstI. The borderline frequency of the mutant allele (0.01) is in agreement with previous observations suggesting that IAP is considerably less polymorphic than PLAP and GCAP.
Alkaline Phosphatase↗
Ethnic differences in enzyme and DNA polymorphisms of human tissue-specific alkaline phosphatases.
Enzyme and DNA polymorphisms and haplotypes of tissue-specific alkaline phosphatase genes were studied in Finns, Saamis and Swedes. In placental alkaline phosphatase (PLAP) restriction fragment length polymorphisms (RFLPs), found after digestion with RsaI and PstI, no significant population differences were observed. The PstI RFLP of the germ cell alkaline phosphatase (GCAP) locus showed significant allele frequency variations between Finns and Swedes (p = 0.014) and between Saamis and Swedes (p = 1 x 10(-4)). Electrophoretic enzyme variants of PLAP were studied in Finns and Swedes. The PLAP variant 18 (D in older nomenclature) was found at a polymorphic frequency in the Finnish sample. In all populations, strong linkage disequilibria were found between the RFLPs and between RFLPs and electrophoretic PLAP types. There was, however, one notable exception: between the RsaI RFLP of PLAP and the PstI RFLP of GCAP no linkage disequilibrium was found. Two new RFLPs were observed in the Finnish population sample, a RsaI mutant site in PLAP with a frequency of 0.02 and a KpnI mutant site outside and upstream of the PLAP gene with a frequency of 0.036. In accordance with findings in previous studies at the enzyme level, PLAP also appeared to be more polymorphic than GCAP and intestinal alkaline phosphatase at the DNA level.
Alkaline Phosphatase↗
RsaI and BclI polymorphism of the transferrin receptor gene.
Polymorphism of the transferrin receptor gene has previously not been observed. Here we report two new restriction fragment length polymorphisms (RFLPs) of the transferrin receptor gene. Digestion with RsaI revealed three variable fragments at 1.15, 1.05 and 0.85 kb. After cleavage with BclI, two polymorphic 2.8- and 2.3-kb fragments were found. There was strong linkage disequilibrium between the two RFLPs, and Saamis showed a highly significant difference from Finns and Swedes with respect to allele frequencies. The new polymorphisms of the transferrin receptor gene may be useful markers in population and linkage studies and in studies of associations with body iron stores and susceptibility to genotoxic damage and cancer.
Blotting, Southern↗
Placental alkaline phosphatase types and transplacental IgG transport.
Recently, results have been presented which suggest that placental alkaline phosphatase (PLAP) is an IgG receptor, and that the transplacental transport of IgG from mother to fetus is dependent on the fetal PLAP genotype. In order to confirm the relationship between the PLAP types and transplacental IgG transport, we studied fetal (cord serum) IgG levels in relation to PLAP types, quantitative variations in PLAP activity, maternal IgG levels and gestation length. Fetal IgG levels and the fetal/maternal IgG ratio showed no significant correlation with PLAP types and PLAP activity. Thus differences between PLAP types with respect to transplacental IgG transport are unlikely to play a selective role in the maintenance of the PLAP polymorphism. In accordance with results from previous studies, significant correlations were found with maternal IgG levels and gestation length. Perusal of the literature suggests that PLAP is mainly an IgG1 receptor.
Alkaline Phosphatase↗
DNA polymorphisms and haplotypes of human liver/bone/kidney alkaline phosphatase in Finns, Saamis and Swedes.
BclI and SstI restriction fragment length polymorphisms of human liver/bone/kidney or tissue-non-specific alkaline phosphatase were studied in population samples of Finns, Swedes and Swedish Saamis. No significant allele frequency differences were found between the three ethnic groups, but in comparison with a previously reported study of North American Caucasians, a highly significant difference was found with respect to BclI alleles. In contrast to previous findings, a significant linkage disequilibrium was found between BclI and SstI alleles.
Alkaline Phosphatase↗