Search results for " Linkage"
showing 10 items of 174 documents
Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.
2003
Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screenng in specific invitro fertilization (IVF) patient groups, along with FISH analysis of spematozoa in intertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 y…
Determinants of homonym and synonym rates of record linkage in disease registration.
1996
AbstractReliable record linkage is an essential component of the quality of population-based disease registration. Quality assessment of disease registries should, therefore, include quantitative approaches to describe the extent of record-linkage errors. The homonym and synonym rates have been proposed for this purpose. The homonym rate quantifies the proportion of distinct patients excluded from registration due to erroneous linkage with other patients. The synonym rate quantifies the proportion of unrecognized duplicate notifications on patients already registered in the registry. This paper provides an algebraic assessment of the determinants of both rates. It is shown how the homonym a…
Effects of record linkage errors on disease registration
1998
Abstract:Reliable record linkage is a prerequisite for high-quality population-based disease registration. Rapid developments in computer processing have made record linkage both more efficient and more reliable in recent years. At the same time, concerns about confidentiality increasingly hinder record linkage in many disease registries. This paper provides basic algebraic models describing the effects of record linkage errors on monitoring disease incidence. Homonym errors, that is, erroneous linkage of records that pertain to distinct individuals, lead to underestimation of incidence in the registry population. The degree of underestimation strongly depends on the discriminating power of…
Phenotype Correlation and Intergenerational Dynamics of the Friedreich Ataxia GAA Trinucleotide Repeat
1997
Summary The Friedreich ataxia (FA) mutation has recently been identified as an unstable trinucleotide GAA repeat present 7–22 times in the normal population but amplified as many as > 1, 000 times in FA. Since it is an autosomal recessive disease, FA does not show typical features observed in other dynamic mutation disorders, such as genetic anticipation. We have analyzed the GAA repeat in 104 FA patients and 163 carrier relatives previously defined by linkage analysis. The GAA expansion was detected in all patients, most (94%) of them being ho-mozygous for the mutation. We have demonstrated that clinical variability in FA is related to the size of the expanded alleles: milder forms of the …
Mitochondrial DNA Portrait of Latvians: Towards the Understanding of the Genetic Structure of Baltic-Speaking Populations
2005
Summary Mitochondrial DNA (mtDNA) variation was investigated in a sample of 299 Latvians, a Baltic-speaking population from Eastern Europe. Sequencing of the first hypervariable segment (HVS-I) in combination with analysis of informative coding region markers revealed that the vast majority of observed mtDNAs belong to haplogroups (hgs) common to most European populations. Analysis of the spatial distribution of mtDNA haplotypes found in Latvians, as well as in Baltic-speaking populations in general, revealed that they share haplotypes with all neighbouring populations irrespective of their linguistic affiliation. Hence, the results of our mtDNA analysis show that the previously described s…
Elusive amines and cluster headache: mutational analysis of trace amine receptor cluster on chromosome 6q23.
2004
Cluster headache (CH) is characterised by unilateral pain and ipsilateral autonomic features. To date, no molecular genetic evidence has been shown for CH. Small pedigrees and low penetrance render the identification of the CH-gene quite difficult. Nonetheless the association of CH and migraine to a new class of amine, namely trace or elusive amines such as tyramine, octopamine and synephrine, has recently been demonstrated. In particular, in comparison to healthy control subjects, all these neurotransmitters have been found to be greatly elevated in CH sufferers in plasma and platelets both in active and remission periods. A cluster of gene-encoding G-protein-coupled receptors that bind an…
“The Linosa Study”: Epidemiological and heritability data of the metabolic syndrome in a Caucasian genetic isolate
2009
Abstract Background and aims Growing evidence suggests that the metabolic syndrome (MetS) has both a genetic and environmental basis. To evaluate the possibility of a further genetic analysis, we estimated prevalence rates and heritabilities for the MetS and its individual traits in the adult population of Linosa, a small and isolated Italian Island in the southern-central part of the Mediterranean Sea. Methods and results The Linosa Study (LiS) group consisted of 293 Caucasian native subjects from 51 families (123 parents; 170 offsprings). The MetS was defined according to NCEP/ATP III criteria and the following prevalence rates were calculated: hyperglycaemia 20.3%; central obesity 34.9%;…
Evaluation of Record Linkage Methods for Iterative Insertions
2009
Summary Objectives: There have been many developments and applications of mathematical methods in the context of record linkage as one area of interdisciplinary research efforts. However, comparative evaluations of record linkage methods are still underrepresented. In this paper improvements of the Fellegi-Sunter model are compared with other elaborated classification methods in order to direct further research endeavors to the most promising methodologies. Methods: The task of linking records can be viewed as a special form of object identification. We consider several non-stochastic methods and procedures for the record linkage task in addition to the Fellegi-Sunter model and perform an e…
Localization of quantitative trait loci for diapause and other photoperiodically regulated life history traits important in adaptation to seasonally …
2015
Seasonally changing environments at high latitudes present great challenges for the reproduction and survival of insects, and photoperiodic cues play an important role in helping them to synchronize their life cycle with prevalent and forthcoming conditions. We have mapped quantitative trait loci (QTL) responsible for the photoperiodic regulation of four life history traits, female reproductive diapause, cold tolerance, egg-to-eclosion development time and juvenile body weight in Drosophila montana strains from different latitudes in Canada and Finland. The F2 progeny of the cross was reared under a single photoperiod (LD cycle 16:8), which the flies from the Canadian population interpret a…
Breast cancer genome-wide association studies: there is strength in numbers.
2012
Breast cancer (BC) is a heterogeneous disease that exhibits familial aggregation. Family linkage studies have identified high-penetrance genes, BRCA1, BRCA2, PTEN and TP53, that are responsible for inherited BC syndromes. Moreover, a combination of family-based and population-based approaches indicated that genes involved in DNA repair, such as CHEK2, ATM, BRIP and PALB2, are associated with moderate risk. Therefore, all of these known genes account for only 25% of the familial aggregation cases. Recently, genome wide association studies (GWAS) in BC revealed single nucleotide polymorphisms (SNPs) in five novel genes associated to susceptibility: TNRC9, FGFR2, MAP3K1, H19 and lymphocyte-spe…