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At least 433 records · Page 24Linked to original sources
PubMed1982

The locus for apolipoprotein E (apoE) is linked to the complement component C3 (C3) locus on chromosome 19 in man.

By two-dimensional electrophoresis of human serum a genetically determined polymorphism of apolipoprotein E (apoE) can be demonstrated. Three alleles occur with appreciable frequency in Caucasian populations. In the present study the segregation of apoE and complement component C3 (C3) types in material from Norwegian families has been studied. Linkage has convincingly been demonstrated between the two loci with a lod score of 3.00 in males at a recombination fraction of 13%. As it is known that the C3 locus is situated on chromosome 19 in man, apoE can be located to this specific chromosome. Positive linkage data do not, to our knowledge, at present exist with regard to other apolipoproteins.

Adult↗
PubMed1997

Mapping genes controlling hematocrit in the spontaneously hypertensive rat.

The genes that determine the baseline hematocrit level in humans and experimental animals are unknown. The spontaneously hypertensive rat (SHR), the most widely used animal model of human essential hypertension, exhibits an increased hematocrit when compared with the normotensive Brown Norway (BN-Lx) strain (0.54 +/- 0.02 vs. 0.44 +/- 0.02, p < 0.01). Distribution of hematocrit values among recombinant inbred (RI) strains derived from SHR and BN-Lx progenitors was continuous, which suggests a polygenic mode of inheritance. The narrow heritability of the hematocrit was estimated to be 0.32. The Eno2 marker on Chromosome (Chr) 4 showed the strongest association (p < 0.0001) with the observed variability of hematocrit among RI strains. The erythropoietin (Epo) gene, originally reported to be syntenic with Eno2, has been mapped to Chr 12, thus excluding it as a potential candidate gene for the increased hematocrit in the SHR. The current linkage data extend homologies between rat, mouse, and human chromosomes.

Animals↗
PubMed1998

A male-female bias in type 1 diabetes and linkage to chromosome Xp in MHC HLA-DR3-positive patients.

It is generally assumed that the male:female (M:F) ratio in patients with type 1 (insulin-dependent) diabetes mellitus (IDDM) is 1. A recent survey, however, revealed that high incidence countries (mainly European) have a high M:F ratio and low incidence ones (Asian and African) have a low M:F ratio. We have now analysed the M:F ratio according to genotype at the major locus, the major histocompatibility complex (MHC; IDDM1). There are two main IDDM1 susceptibility haplotypes, HLA-DR3 and -DR4, which are present in 95% of Caucasian cases. We report here that in medium/high incidence Caucasian populations from the United States of America, United Kingdom and Sardinia (1307 cases), the bias in male incidence is largely restricted to the DR3/X category of patients (X not = DR4) with a M:F ratio of 1.7 (P=9.3x10(-7)), compared with a ratio of 1.0 in the DR4/Y category (Y;DR3). This is additional evidence for significant heterogeneity between the aetiology of 'DR4-associated' and 'DR3-associated' diabetes. We analysed linkage of type 1 diabetes to chromosome X, and as expected, most of the linkage to Xp13-p11 was in the DR3/X affected sibpair families (n=97; peak multipoint MLS at DXS1068=3.5, P=2.7x10(-4); single point MLS=4.5, P=2.7x10(-5)). This is evidence for aetiological heterogeneity at the IDDM1/MHC locus and, therefore, in the search for non-MHC loci in type 1 diabetes, conditioning of linkage data by HLA type is advised.

Adolescent↗
PubMed1979

Genetic mapping of the locus controlling structural variations of murine C3 in the chromosome 17.

Backcross progeny, (NC X TF/GnLe)F1 X TF/GnLe, was tested for C3 allotype controlled by C3-1 and the expression of mutant gene tf, repeated loss and regrowth of hair. The recombination frequency between these two loci both located in chromosome 17 of the mouse was 24%. Taken together with our previous linkage data, C3-1 is now localized to a position 11 cm more distal than H-2 on chromosome 17.

Animals↗
PubMed1990

Correlation between meiotic behavior and breakpoints with respect to G-bands in two X-4 mouse translocations: T(X;4)7R1 and T(X;4)8R1.

The meiotic synaptic behavior of male mice heterozygous for one of two X-4 translocations was examined to test a recently advanced hypothesis (Ashley, 1988) suggesting that it is possible to predict the synaptic behavior (nonhomologous vs. homologous) and recombinational parameters (suppression vs. nonsuppression of crossing-over) of a chromosome aberration from mitotic G-band breakpoint data. The hypothesis was based on prior observations of synaptic behavior in a series of X-autosome translocations in mice. The breakpoints of the translocation T(X;4)7R1 are both in G-light bands. As predicted by the hypothesis, synapsis was restricted to homology. In contrast, one breakpoint of the translocation T(X;4)8R1 lies in a "stippled" band of the standard diagrams of Nesbitt and Francke (1981). As predicted (Ashley, 1988), "stippled" bands are shown here to synapse nonhomologously, i.e., they behave as "G-dark." The linkage data, as they relate to the synaptic data and the predictions of the hypothesis, are also discussed.

Animals↗
PubMed2002

[Analysis of biases in epidemiological knowledge of road accidents in France].

BACKGROUND: In France, as in many countries, road casualty statistics are mostly based on police reports. It is generally recognized that these data are incomplete but no measurement has been made of the degree of under-reporting and thus of associated biases. This study aims to demonstrate and quantify these biases. METHODS: The study compares, after data linkage, the 10,202 people reported injured or killed in 1996 in the medical road accident victims Register in the Département du Rhône (France), with the 4,572 victims reported by the police during the same year and in the same area. This Département was chosen, as it is the only region in France where these two independent data sources coexist. Two types of possible biases are studied: injury severity classification bias and selection bias induced by underreporting. RESULTS: The study shows that the definition of "serious injury" used by the police exaggerates the severity of the victim's condition in over half the cases. This bias depends on road user group. This bias is maximum for pedestrians: compared to a slightly injured car occupant, a pedestrian with the same injury severity level has significantly more chance to be considered as severely injured (RR=1.78; 95% CI: 1.11-2.87). Conversely, significant selection biases are related to data collection by the police. The multivariate analysis shows that the underreporting of victims increases if no third party is involved (i.e. without any other vehicle or pedestrian), and reduces with injury severity. It also varies by road user group (with the largest underreporting for cyclists). Among the most seriously injured in accidents involving third parties, motor cyclists and car users are the most reported category and pedestrians the least (RR=0.80; 95% CI: 0.70-0.92). Biases in Register selection are much more limited and basically concern underreporting of victims of minor accidents who did not require medical care. CONCLUSIONS: This study confirms and quantifies misleading distortions in police statistics used to assess road accidents. These results concern the relevant indicators to be used to define road safety issues.

Accidents, Traffic↗
PubMed1996

The gene encoding collagen alpha1(V)(COL5A1) is linked to mixed Ehlers-Danlos syndrome type I/II.

The Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders in which cutaneous fragility and ligamentous laxity often combine with vascular, gastrointestinal, and skeletal deformities. There is considerable phenotypic overlap between the more common forms of EDS (types I and II), in which specific molecular defects have not yet been identified. Recently, genetic linkage has been demonstrated between the COL5A1 gene, which encodes the alphal chain of type V collagen, and EDS type II in a large British kindred. Using a polymorphic intragenic simple sequence repeat at the COL5A1 locus, we now demonstrate tight linkage to EDS type I/II in a three-generation family, giving a LOD score (log10 of the odds for linkage) of 4.07 at zero recombination. The variation in expression in this family suggests that EDS types I and II are allelic, and the linkage data support the hypothesis that mutation in COL5A1 can cause both phenotypes.

Aged↗
PubMed1984

Isolation of transposon Tn551 insertions near chromosomal markers of interest in Staphylococcus aureus.

A procedure was developed to isolate insertions of transposon Tn551 near other markers of interest on the chromosome of Staphylococcus aureus NCTC 8325. When an inoculum of strain 8325-4 carrying a thermosensitive mutant of plasmid pI258 (on which Tn551 resides) was inoculated into brain heart infusion agar plus erythromycin and grown to saturation at 43 degrees C, the transforming DNA extracted from this population of cells contained a random collection of different chromosomal insertions of Tn551; this DNA is referred to as pooled Tn551 DNA. When erythromycin-sensitive recipient strains containing chromosomal markers of interest were transformed with pooled Tn551 DNA, and the resulting Emr transformants were screened for coinheritance of the donor allele of the marker of interest, insertions of Tn551 were isolated near several markers, including fus-149, tet-3490, mec-4916, pig-131, ilv-129, pur-140, and uraA141. Many of the insertions were within the linkage groups that contained these markers, and several insertions occupied different positions between the linkage groups in heretofore undefined regions of the circular chromosomal map of S. aureus. These insertions of transposon Tn551 extend the known limits of the existing linkage groups, provide linkage data and map locations for markers not previously mapped, and provide a means to map markers which cannot be directly selected.

Chromosome Mapping↗
PubMed2003

Multigenic control of disease severity after virulent Mycobacterium tuberculosis infection in mice.

Following challenge with virulent Mycobacterium tuberculosis, mice of the I/St inbred strain exhibit shorter survival time, more rapid body weight loss, higher mycobacterial loads in organs, and more severe lung histopathology than mice of the A/Sn strain. We previously performed a genome-wide scan for quantitative trait loci (QTLs) that control the severity of M. tuberculosis-triggered disease in [(A/Sn x I/St) F1 x I/St] backcross-1 (BC1) mice and described several QTLs that are significantly or suggestively linked to body weight loss. In the present study we expanded our analysis by including the survival time phenotype and by genotyping 406 (A/Sn x I/St) F2 mice for the previously identified chromosomal regions of interest. The previously identified 12-cM-wide QTL on distal mouse chromosome 3 was designated tbs1 (tuberculosis severity 1); the location of the QTL on proximal chromosome 9 was narrowed to a 9-cM interval, and this QTL was designated tbs2. Allelic variants of the tbs2 locus appeared to be involved in control of both body weight loss and survival time. Also, the data strongly suggested that a QTL located in the vicinity of the H-2 complex on chromosome 17 is involved in control of tuberculosis in mice of both genders, whereas the tbs1 locus seemed to have an effect on postinfection body weight loss in female mice. Interestingly, these loci appeared to interact with each other, which suggests that there might be a basic genetic network for the control of intracellular parasites. Overall, linkage data reported here for F2 mice are in agreement with, and add to, our previous findings concerning the control of M. tuberculosis-triggered disease in the BC1 segregation.

Animals↗
PubMed2006

Association of schizophrenia and autoimmune diseases: linkage of Danish national registers.

OBJECTIVE: Individuals with schizophrenia and their relatives tend to have either higher or lower than expected prevalences of autoimmune disorders, especially rheumatoid arthritis, celiac disease, autoimmune thyroid diseases, and type 1 diabetes. The purpose of the study was to estimate the association of schizophrenia with these disorders as well as a range of other autoimmune diseases in a single large epidemiologic study. METHOD: The Danish Psychiatric Register, the National Patient Register, and a register with socioeconomic information were linked to form a data file that included all 7,704 persons in Denmark diagnosed with schizophrenia from 1981 to 1998 and their parents along with a sample of matched comparison subjects and their parents. The data linkage required that the autoimmune disease occur before the diagnosis of schizophrenia. RESULTS: A history of any autoimmune disease was associated with a 45% increase in risk for schizophrenia. Nine autoimmune disorders had higher prevalence rates among patients with schizophrenia than among comparison subjects (crude incidence rate ratios ranging from 1.9 to 12.5), and 12 autoimmune diseases had higher prevalence rates among parents of schizophrenia patients than among parents of comparison subjects (adjusted incidence rate ratios ranging from 1.3 to 3.8). Thyrotoxicosis, celiac disease, acquired hemolytic anemia, interstitial cystitis, and Sjögren's syndrome had higher prevalence rates among patients with schizophrenia than among comparison subjects and also among family members of schizophrenia patients than among family members of comparison subjects. CONCLUSIONS: Schizophrenia is associated with a larger range of autoimmune diseases than heretofore suspected. Future research on comorbidity has the potential to advance understanding of pathogenesis of both psychiatric and autoimmune disorders.

Age of Onset↗
PubMed1987

The Kidd (JK) blood group locus assigned to chromosome 18 by close linkage to a DNA-RFLP.

The close linkage between the PstI-restriction fragment length polymorphism (RFLP) disclosed by the L2.7 genomic DNA probe and the Kidd blood group locus is described. The maximum lod score is +8.53 at recombination fraction theta = 0.03. The upper probability limit of the recombination fraction is theta 1 = 0.11. The L2.7 probe, previously assigned provisionally to chromosome 17, is by the present study assigned to chromosome 18. This also assigns the Kidd blood group locus (JK) to chromosome 18. Accepting previous deletion mapping, the shortest regions of overlap (SRO) for JK is 18q11-12, whereas one of our hybrids assigns L2.7 to 18p11-pter, suggesting centromeric localisation of the linkage group. JK has been assigned previously to chromosome 2 because of its provisional linkage to IGK which in turn has been mapped to 2p12. Our own JK-IGK linkage data do in fact support the previous positive lod scores at high recombination fractions (total lods +4.12 at theta1 = 0.30). No obvious explanation for the conflicting gene mapping data is found.

Blood Group Antigens↗
PubMed1996

Autosomal dominant spastic paraplegia with anticipation maps to a 4-cM interval on chromosome 2p21-p24 in a large German family.

Autosomal dominant familial spastic paraplegias (AD-FSP) are a group of genetically heterogeneous diseases characterised by a progressive spasticity of the lower limbs. Three loci have already been identified by genetic linkage studies on chromosomes 2p, 14q and 15q. Here we present linkage data from a large German family displaying AD-FSP with anticipation which confirms the existence of the FSP2 locus on chromosome 2p. The recombination events observed in our family define the critical region for the FSP2 gene to be within a 4-cM interval, flanked by markers D2S400 and D2S367. Moreover, clinical data from our family show evidence of anticipation, a phenomenon caused by trinucleotide expansion in several other neurodegenerative diseases.

Chromosome Mapping↗
PubMed1991

X-linked megalocornea. Ocular findings and linkage analysis.

A family with X-linked megalocornea (XMC) is presented. The most typical ocular features of the disease (cornea globosa, arcus lipoides, mosaic dystrophy of the cornea, pigment dispersion, and cataract) are described and their diagnostic value is discussed by reviewing the literature. Linkage data suggest that the XMC locus maps in the region Xq13-q25, most probably in Xq21-q22.

Adult↗
PubMed1990

An HhaI polymorphism is present in factor IX genes of Asian subjects.

Hemophilia B is caused by decreased factor IX procoagulant activity. An HhaI restriction site polymorphism near the factor IX gene has been detected by the polymerase chain reaction. Frequency and linkage data already observed in Caucasians are confirmed and the polymorphism is also prevalent in the factor IX genes of Black and Asian populations.

Asian People↗
PubMed2005

Do marginal changes in PHI membership accurately predict marginal changes in PHI use in Western Australia?

OBJECTIVE: Annual trends in the rate of utilisation of PHI in three different clinical categories were compared with published trends in PHI membership to assess the degree to which PHI membership predicts PHI use in Western Australia. METHODS: The WA Data Linkage System was used to extract all hospital morbidity records in Western Australia from 1981 to 2001. The adjusted annual incidence rate ratio of hospitalisation as a privately insured patient versus a public (Medicare) patient was estimated using Poisson regression in each clinical category across three age groups in each year. The rate ratios were graphed as segmented trend lines and compared with published data for trends in PHI membership. RESULTS: The most significant changes in the use of PHI versus the public system occurred between 1981 and 1984 overall clinical categories. These changes were consistent with those documented for PHI membership. From 1992 onwards, significant changes in the trend were observed in the surgical clinical category, compared with the medical and obstetric clinical categories. Further, the trend observed in the surgical clinical category at this time was inconsistent with that documented for PHI membership. Between 2000 and 2001, only the surgical clinical category showed a similar change in trend as that documented for PHI membership. CONCLUSION: Between 1981 and 1991 the timing and direction of changes in PHI membership were found to be congruent with that of PHI use in all three clinical categories. However, between 2000 and 2001 trends in PHI membership were only congruent with trends in PHI use in the surgical clinical category. We conclude that investigating marginal changes in PHI membership represents an incomplete method for assessing the effectiveness of policies aimed at reducing the pressure on the public system.

Adolescent↗
PubMed1984

The Pk-3 gene determines both the heart, M1, and the kidney, M2, pyruvate kinase isozymes in the mouse; and a simple electrophoretic method for separating phosphoglucomutase-3.

We have found that in mice carrying Pk-3r, an allele leading to loss or activity of kidney pyruvate kinase, the activity of heart pyruvate kinase is also diminished. Electrophoretic studies on tissues from mice carrying Pk-3r and/or Pk-3b, an allele determining an electrophoretically detectable variant, show that Pk-3 affects the expression of both the heart, M1, and the kidney, M2, pyruvate kinase isozymes. These results, together with linkage data, indicate that both isozymes are determined by the same structural gene, Pk-3. We also report a simple method for separating phosphoglucomutase-3 (PGM-3) by electrophoresis on cellulose acetate plates.

Animals↗
PubMed2002

Visual acuity impairment and mortality in US adults.

OBJECTIVE: To examine the associations between reported visual impairment (VI) and mortality in a nationally representative sample of US adults. METHODS: The National Health Interview Survey is a multistage probability survey of the US civilian population. Adults within households were administered questions about VI and selected eye diseases (n = 116 796). Mortality linkage data with more than 96% of the 1986-1994 survey participants were available through December 31, 1997. Statistical analyses included Cox proportional hazards regression analysis. MAIN OUTCOME MEASURES: All-cause, cardiovascular disease-related, and cancer-related mortality. RESULTS: A total of 327 participants (0.3%) had severe bilateral VI; an additional 4754 (4%) had some VI and/or severe VI in at least one eye. Mortality linkage identified 8949 deaths. After controlling for survey design, age, race, marital status, educational level, reported health status, glaucoma, cataract, and retinopathy, women, but not men, with reported severe bilateral VI were at a significantly increased risk of death relative to their counterparts without VI (hazard ratio [95% confidence interval], 2.21 [1.61-3.02] and 1.33 [0.96-1.84], respectively); risk of mortality was also slightly but significantly elevated in women and men with some reported VI compared with those reporting no VI. Similar patterns of associations were found for cardiovascular disease-related mortality. Risk of cancer-related mortality was not associated with VI. CONCLUSION: Reported severe bilateral VI and, to a smaller extent, less severe VI are associated with an increased risk of all-cause mortality and cardiovascular disease-related mortality in US women; there is weaker evidence for an association between VI and mortality in US men.

Adolescent↗
PubMed1991

Linkage mapping of autosomal dominant retinitis pigmentosa (RP1) to the pericentric region of human chromosome 8.

Linkage mapping in a large, seven-generation family with type 2 autosomal dominant retinitis pigmentosa (ADRP) demonstrates linkage between the disease locus (RP1) and DNA markers on the short arm of human chromosome 8. Five markers were most informative for mapping ADRP in this family using two-point linkage analysis. The markers, their maximum lod scores, and recombination distances were ANK1 (ankyrin)--2.0 at 16%; D8S5 (TL11)--5.3 at 17%; D8S87 [a(CA)n repeat]--7.2 at 14%; LPL (lipoprotein lipase)--1.5 at 26%; and PLAT (plasminigen activator, tissue)--10.6 at 7%. Multipoint linkage analysis, using a simplified pedigree structure for the family (which contains 192 individuals and two inbreeding loops), gave a maximum lod score of 12.2 for RP1 at a distance 8.1 cM proximal to PLAT in the pericentric region of the chromosome. Based on linkage data from the CEPH (Paris) reference families and physical mapping information from a somatic cell hybrid panel of chromosome 8 fragments, the most likely order for four of these five loci and the diseases locus is 8pter-LPL-D8S5-D8S87-PLAT-RP1. (The precise location of ANK1 relative to PLAT in this map is not established). The most likely location for RP1 is in the pericentric region of the chromosome. Recently, several families with ADRP with tight linkage to the rhodopsin locus at 3q21-q24 were reported and a number of specific rhodopsin mutations in families with ADRP have since been reported. In other ADRP families, including the one in this study, linkage to rhodopsin has been excluded. Thus mutations at two different loci, at least, have been shown to cause ADRP. There is no remarkable clinical disparity in the expression of disease caused by these different loci.

Base Sequence↗