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Results for “Data Linkage”

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At least 109 records · Page 6Linked to original sources
PubMed1987

Further linkage data on Norrie disease.

We obtained a LOD score of +1.61 using DNA marker L1.28 in 5 generations of a family with Norrie disease, raising the total LOD score to +5.42. There have been no recombinations between the 2 loci in any family to date, making the marker useful for genetic counseling.

Blindness↗
PubMed1999

Comparison of GENEHUNTER and MFLINK for analysis of COGA linkage data.

We compared the NPLALL statistic from GENEHUNTER with two-point and three-point MALODs and MFLODs from MFLINK for all autosomal markers in the Collaborative Study on the Genetics of Alcoholism (COGA) data set. In general MFLINK produced more significant results than GENEHUNTER and implicated two regions containing candidate genes (ADH3 and DRD2). Many regions of interest identified in other studies reported at this workshop produced MALODs significant at p < or = 0.05, but these would not have been picked up by GENEHUNTER unless a less significant threshold were used.

Alcoholism↗
PubMed1997

A meta-analysis of chromosome 18 linkage data for bipolar illness.

We find a meta-data set (715 families, up to 1,124 sib pairs) for bipolar illness to have a strong signal in a 10 cM region around D18S40, and excess paternal sharing on the q arm near marker D18S64. We describe a method for meta-analysis of microsatellite marker data using affected sib-pair (ASP) methodology. Inherent difficulties in such analysis include heterogeneity of allele frequencies and protocol design, measurement errors in genotyping, and map construction. Using identity-by-descent (IBD) allele sharing as the dependent variable, a logistic regression to test for heterogeneity finds only mild heterogeneity, and a limited parent-of-origin effect.

Alleles↗
PubMed1988

Inheritance and linkage data for an unusual combination of genes (at the LKE, PI and C6 loci) in a single large sibship.

Analysis of the groups of a large sibship showed that the locus for the blood group LKE is not closely linked to the loci for MNS, Rh, HLA, Pi, Gm and C6 and is genetically independent of the loci for P1, K, Xg, Au, secretor, and C3. The locus for the Auberger (Au) blood group was shown to be genetically independent of the locus for the blood group Kell and of the loci for C3, C6, Gc, HLA, Pi and Gm groups.

Blood Group Antigens↗
PubMed2000

Correcting for ascertainment bias of relative-risk estimates obtained using affected-sib-pair linkage data.

Locus-specific sibling relative risk is often estimated using affected-sib-pair lod score analysis of affected sibships and may be used to decide whether to continue or discontinue the search for additional susceptibility genes. We showed that relative-risk estimates obtained using affected-sib-pair data are asymptotically unbiased when each pair is given a weight inversely proportional to the sibship ascertainment probability. Here we show by simulation that the extent of the bias of relative risks estimated using the incorrect ascertainment weights is small for dominant models, but large for single-locus recessive models and some two-locus heterogeneity models. Since in practice the ascertainment scheme is often unknown, we investigate methods for jointly estimating ascertainment and relative risks from affected-sibship data. Given a sufficient sample size, a reasonable estimate of relative risk may always be obtained using only affected pairs from sibships with two affected and no unaffected siblings. This estimate, which has a large variance, may then be used in a three-stage procedure (which we call the alpha method) to estimate consistently both the ascertainment probabilities and the relative risks with greater precision. We additionally propose correction factors to eliminate small-sample bias of relative risks and investigate the bias due to error in the estimate of disease locus location.

Bias↗
PubMed1986

Use of Neurospora spore killer strains to obtain centromere linkage data without dissecting asci.

Use of a centromere-linked Spore killer gene Sk reduces manyfold the labor involved in obtaining tetrad data that would otherwise require ordered dissection of intact linear eight-spored asci. Heterozygous crosses are made for Spore killer (SkK X SkS) and for markers to be tested. In such crosses only SkK ascospores survive. The four viable (SkK) and four aborted (SkS) ascospores of each ascus are ejected from the perithecium as a physically disordered group. The four surviving SkK ascospores of individual asci are germinated and scored. SkK segregates from SkS at the first meiotic division. If both marker alleles are represented in the surviving products, they must therefore have segregated from one another at the second division. Four-spore (Fsp) genes have been used to eliminate one postmeiotic nuclear division, so that only two ascospores per ascus need to be scored. The Spore killer method has been useful for mapping closely linked genes in centromere regions, for identifying genes that are far out on chromosome arms, for obtaining information on meiotic crossing-over, and for comparing linkages in different species.

Cell Division↗
PubMed1990

Familial dyslexia: use of genetic linkage data to define subtypes.

Specific reading disability is an example of a complex behavioral disorder which is clinically heterogeneous. It is probably also heterogeneous at the levels of etiology and process (pathogenesis), but there may not be a 1:1:1 mapping of etiology to process to clinical outcome. Thus, classification of cases by clinical features may not lead to discovery of the underlying processes or etiologies, and it may be profitable to define subgroups by etiology. There is evidence for genetic etiology in some cases, but there is genetic heterogeneity as well. Possible genetic models for specific reading disability include polygenic, oligogenic, and single gene inheritance, and there are several types of genetic analysis that can be used to determine which of these modes of inheritance may be present. Identification of individual genes is possible in single gene and oligogenic disorders. Clinical studies and molecular analysis can then be used to determine gene function.

Adult↗
PubMed1990

Laryngeal cancer in Denmark: a nationwide longitudinal study based on register linkage data.

To identify high and low risk groups for laryngeal cancer in Denmark, all individuals aged 30-74 in the 1970 census were followed up over 10 years. Census data were linked with the Central Population Register to identify persons who died or emigrated during the follow up, and with the Danish Cancer Register to identify cases of laryngeal cancer. Individuals were categorised according to sex, age, and sociodemographic characteristics as declared on the census forms. A multivariate analysis was carried out by means of multiplicative Poisson models. The study showed that the risk of laryngeal cancer was strongly related to sociodemographic factors. The risk for skilled workers living in Copenhagen (relative risk (RR) 4.76, 95% confidence interval (CI) 3.61-6.28) was estimated to be almost five times higher than the risk for men self employed in agriculture and living in rural areas. The variation in the risk of laryngeal cancer is not fully explained by known variations in tobacco and alcohol consumption, and this study highlights additional risk factors particularly related to occupation and marital state.

Adult↗
PubMed2006

Extreme cause-specific mortality in a cohort of adult prisoners--1988 to 2002: a data-linkage study.

OBJECTIVES: Describe the standardized mortality ratio (SMR) and its trend in adults who have served time in prison. DESIGN: A retrospective cohort study of 85,203 adults imprisoned in New South Wales (NSW), Australia, between 1 January 1988 and 31 December 2002. METHODS: We obtained information on deaths by record linkage with the Australian National Death Index (NDI). Mortality rates were estimated using the person-time method. SMRs were calculated using sex, age, and calendar-specific death rates from the NSW population. Time trends in SMRs were assessed using the test for linear trends. RESULTS: The median overall follow-up of the cohort was 7.7 years. We identified 5137 deaths (4714 men, 423 women) among the cohort of which the vast majority (4834, 94%) occurred following release from custody. All-cause SMR was 3.7 (95% CI: 3.6-3.8) in men and 7.8 (95% CI: 7.1-8.5) in women. SMRs were substantially raised for deaths due to mental and behavioural disorders (men: 13.2, 95% CI: 12.3-14.0; women: 62.8, 95% CI: 52.7-74.9) and drug-related deaths (men: 12.8, 95% CI: 12.2-13.5; women: 50.3, 95% CI: 43.7-57.8). The SMR for death by homicide was 10.2 (95% CI: 8.9-11.7) in men and 26.3 (95% CI: 17.8-39.0) in women. Aboriginal men were 4.8 times, and Aboriginal women 12.6 times, more likely to die than the general NSW population. Over the study period on average all-cause SMR decreased significantly in men (p = 0.003) and women (p = 0.05) largely due to the decline in SMRs for drug-related deaths and suicide. CONCLUSION: In the largest study so far reported, mortality of male and female offenders was far greater than expected for all major causes, especially deaths caused by drug overdose. Despite some indication of a reduction in excess mortality in recent years, there remains an overwhelming need for enhanced responses to mental health and drug problems for people who have been in prison.

Adult↗