The genetic epidemiology of hypertension: a review of past studies and current results for 948 persons in 48 Utah pedigrees.
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Adolescent↗
Biomedical subjects
L B Jorde
Publications and source records attributed to L B Jorde.
Historical epidemiology of smallpox in Aland, Finland: 1751-1890.
We analyze a 140-year series of smallpox deaths in the Aland Islands, Finland. Vaccination, introduced in 1805, dramatically reduced the annual number of smallpox deaths. It also influenced the age distribution of smallpox deaths, changing smallpox from a childhood disease before 1805 to one which affected both adults and children after 1805. This appears to be due to the fact that Alanders were usually vaccinated only once during childhood and often lost their immunity during adulthood. Spectral analysis of the prevaccination time series of smallpox deaths demonstrates a strong seven-year periodicity, reflecting the amount of time necessary to build up a cohort of nonimmune individuals. After the introduction of vaccination, the periodicity changes to eight years. The probability that a parish in Aland was affected by a smallpox epidemic is shown to be highly correlated with migration patterns and parish population sizes.
Finland↗
Genetic distances between the Utah Mormons and related populations.
Gene frequency data, consisting of six red cell antigen loci, nine electrophoretic systems, and HLA-A and -B are reported for the Utah Mormon population. These are compared statistically to gene frequencies from at U.S. population, 13 European populations, and seven populations from three religious isolates. The Mormon gene frequencies are similar to those of their northern European ancestors. This is explained by the large founding size of the Mormon population and high rates of gene flow. In contrast, the religious isolates (Amish, Hutterites, and Mennonites) show marked divergence from their ancestral populations and each other, due to isolation and random genetic drift. The HLA loci and electrophoretic loci presented here yield sets of genetic distances that are highly correlated (r = .734) and that both correspond closely to the actual geographic distances among the European populations. The genetic distances based on red cell antigen loci correspond less closely to the geographic distances and exhibit lower correlations with both the HLA and electrophoretic loci (r = .524 and r = .565, respectively).
Alleles↗
Lack of association of diagonal earlobe crease with other cardiovascular risk factors.
The relationship between diagonal earlobe crease and coronary risk factors, controlling for age and sex effects, was tested in 686 persons. A positive correlation (rho=.86, P<.001) is obtained between age and percentage of persons with earlobe creases in each one-year age interval; no sex difference is seen. To test for associations between cardiovascular risk factors and earlobe creases, 67 persons with creases are compared with 67 controls (matched by age and sex) without creases, using the following variables: diastolic and systolic blood pressures, cigarette smoking, weight, height, scapular skinfold thickness, serum cholesterol level, high-density lipoprotein level, intracellular sodium, sodium-lithium countertransport, plasma renin level and the presence of diabetes and hypertension. None of these variables differs significantly between cases and controls, indicating that the previously documented association between earlobe crease and coronary heart disease may be independent of these risk factors. Although coronary heart disease has often been shown to aggregate in families, no familial aggregation is found for earlobe creases.
Adolescent↗
Phenotypic heterogeneity in neural tube defects: a clue to causal heterogeneity.
We report here retrospective data on 991 liveborn and stillborn infants with neural tube defects (NTDs) born to Utah residents from January 1, 1940 to December 31, 1979. Data were obtained from multiple sources including approximately 1.25 million vital statistics records and several hundred physician and hospital charts. Causal heterogeneity among NTD patients is presumed because 6% of our cases have other congenital anomalies not part of the NTD field defect. A significant association of NTDs with oral clefts is noted. Sex ratios and empiric recurrence risks for isolated NTDs and NTDs associated with other major malformations are also calculated.
Abnormalities, Multiple↗
Epidemiology and genetics of neural tube defects: an application of the Utah Genealogical Data Base.
The distribution and prevalence of births with neural tube defects in Utah from 1940 to 1979 are analyzed with regard to prevalence rates, secondary sex ratios, seasonality, yearly rates, and time-space clustering. The overall prevalence rate of 1.00 per thousand live births is comparable to that of other populations in the western United States. Analysis of sex ratios indicates a substantially higher proportion of females than males. No significant secular trends or time-space clustering are observed. No seasonality is seen for spina bifida; however, the anencephaly cases are delivered more frequently in the early spring and fall months. Following linkage of the neural tube defect cases to the Utah Genealogical Data Base, application of the genealogical index method shows substantial familial clustering of the disease. The average inbreeding coefficient of the neural tube defect cases is not elevated over that of matched controls. The empirical recurrence risk for the disease is calculated to be 3%, and the heritability estimate is 70%. Likelihood analysis of pedigrees containing spina bifida occulta and spina bifida cystica indicates that they may segregate as an autosomal dominant trait with a penetrance of 75%.
Anencephaly↗
Infant mortality patterns in Aland, Finland.
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Birth Rate↗
Spinal dysraphia as an autosomal dominant defect in four families.
Four families were selected randomly on the basis of the occurrence of spina-bifida cystica and/or spina bifida occulta in one or more family members. Sixty-three relatives were studied clinically and roentgenologically; their roentgenograms were evaluated blindly. Twenty-eight were clinically and roentgenologically normal; 35 were diagnosed as having spina bifida occulta (SBO), spina bifida cystica (SBC), vertebral anomalies, and/or external defects usually interpreted as evidence for SBO. Excluding one proband we found the frequency of SBO to be 19/51 (37%) and the frequency of all types of spinal/vertebral defects (excluding five probands) to be 30/58 (52%). The distribution of these defects in the four families was analyzed using likelihood methods corrected for random ascertainment. The log likelihood values for sporadic, recessive, and dominant models were -26.69, -20.95, and -18.90, respectively, indicating a higher likelihood of autosomal dominant inheritance than sporadic occurrence or recessive inheritance. The penetrance probability in this dominant model, estimated by maximum likelihood, is 0.749 +/- 0.100. Further examination of these data suggest that SBO and SBC represent different expressions of the same dominant gene in these kindreds.
Female↗
A nonparametric distance analysis of biochemical genetic data from the Aland Islands, Finland.
Biochemical genetic data from 3272 individuals from the Aland Islands, Finland, are analyzed using a recently developed set of nonparametric genetic distance measures. These measures are more robust than the traditional methods used in previous studies of this population. While there was general agreement in the results of the traditional and nonparametric approaches, some important differences were seen. In these cases, the nonparametric methods gave result more congruent with population history, geographic pripinquity, and migration patterns. Heterozygosity measures were also calculated for the Aland Islands population and compared to values obtained for Jewish populations. The total heterozygosity values were very similar.
Finland↗
The genetic structure of Iceland.
Gene frequencies and parent-offspring migration data from nine geographic subdivisions in Iceland are analyzed. Estimated values of FST show high genetic homogeneity. Genetic maps are studied and the results are interpreted in the light of social and historical patterns. Actual road distances between subdivisions provide a slightly better indication of geographic isolation by distance than do straight-line distances. A high correlation between genetic structure predicted by migration data and the structure estimated from gene frequencies is obtained.
Aged↗
The genetic structure of the Utah Mormons: migration analysis.
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Christianity↗
Genetic variation in Cumbrians.
Regional variation in the genetic constitution of the Cumbrian population is demonstrated in a survey of blood groups, red cell enzymes, and secretor status in a large sample of schoolchildren. In particular, the south and centre appear to be distinct from the remainder of Cumbria, but in different directions. The features of the central Lake District, tending towards gene frequencies observed in Norway, suggest that it may be a region in which the presence of a relict population is still detectable.
Adolescent↗
Marital migration and genetic structure in Kitee, Finland.
A genetic analysis of marital migration in Kitee, Finland, is presented. The data are based on 9970 marriages which took place between 1750 and 1877. The results of this analysis are compared with those of previous studies of the population of the Aland Islands, Finland. Analysis of inter-subdivision genetic kinship matrices shows that genetic heterogeneity in Kitee is substantially less than in Aland. This is due primarily to higher rates of migration, both between subdivisions and from outside the population, in Kitee compared to Aland. These differences in migration rates can in turn be attributed to greater geographic isolation in Aland and the contrasting social structures of the two populations. Because of differences in geographic structure and population distribution, geographic distance between subdivisions is a better predictor of inter-subdivision genetic kinship in Kitee than in Aland. The Aland Islands are known to have high frequencies of several otherwise rare genetic diseases; in addition, these diseases are distributed very non-randomly among Aland's subdivisions. The genetic structure results presented here suggest that Kitee should have a less unique distribution of genetic diseases.
Emigration and Immigration↗
Gene mapping in isolated populations: new roles for old friends?
Population isolates are increasingly being used in attempts to map genes underlying complex diseases. To further explore the utility of isolates for this purpose, we explore linkage disequilibrium patterns in polymorphisms from two regions (VWF and NF1) in three isolated populations from Finland. At the NF1 locus, the Finnish populations have greater pairwise disequilibrium than populations from Africa, Asia, or northern Europe. However, populations from 'New Finland' and 'Old Finland' do not differ in their disequilibrium levels at either the NF1 or the VWF locus. In addition, disequilibrium patterns and haplotype diversity do not differ between a sample from the Aland Islands, Finland, and a collection of outbred Centre d'Etude du Polymorphisme Humain families. These results show that linkage disequilibrium patterns sometimes differ among populations with different histories and founding dates, but some putative isolated populations may not significantly differ from larger admixed populations. We discuss factors that should be considered when using isolated populations in gene-mapping studies.
Chromosome Mapping↗