Biomedical subjects

G M Lathrop

Publications and source records attributed to G M Lathrop.

At least 19 recordsLinked to original sources

PubMed1992

Antibiotic treatment of venereal disease and Reiter's syndrome in a Greenland population.

OBJECTIVE: To assess the effects of antibiotic treatment of urethritis or cervicitis on the incidence of recurrences of articular symptoms in Reiter's syndrome patients. METHODS: Retrospective evaluation of the medical charts of 109 patients living in Greenland. RESULTS: Thirty-seven percent of the episodes of genitourinary tract inflammation that were not treated or were treated with penicillin were followed by arthritis, compared with 10% of those treated with tetracycline or erythromycin. CONCLUSION: Antibiotics active against Chlamydia trachomatis reduced the risk of postvenereal arthritis in the population studied.

Adult↗

PubMed1992

Genetic linkage analysis of bipolar affective disorder in an Old Order Amish pedigree.

We have used genetic linkage analysis in an effort to identify a gene responsible for bipolar affective disorder (BAD) in an Old Order Amish pedigree. The initial study of this pedigree showed strong evidence for linkage of the chromosome 11p15 markers HRAS1 and the insulin gene (INS) to BAD, whereas a second report found no evidence for linkage. We have independently determined the INS and HRAS1 genotypes from 81 individuals in this pedigree. A polymerase chain reaction (PCR) assay was used to score INS alleles that are difficult to distinguish from one another by conventional agarose gel electrophoresis. In addition, we used four separate diagnostic models to score individuals with psychiatric illness as either affected or unaffected. No evidence of significant linkage between BAD and the markers was found with either two-point or multipoint analysis regardless of which diagnostic model was used. However, exclusion of the region of chromosome 11 between INS and RAS1 as a possible location for the BAD gene in this family depended on the diagnostic model. Further genetic linkage studies with additional DNA markers that span the genome are necessary to determine the chromosomal location of the BAD gene in this family.

Base Sequence↗

PubMed1992

Rat gene mapping using PCR-analyzed microsatellites.

One hundred and seventy-four rat loci which contain short tandem repeat sequences were extracted from the GenBank or EMBL data bases and used to define primers for amplification by the polymerase chain reaction (PCR) of the microsatellite regions, creating PCR-formatted sequence-tagged microsatellite sites (STMSs). One hundred and thirty-four STMSs for 118 loci, including 6 randomly cloned STMSs, were characterized: (i) PCR-analyzed loci were assigned to specific chromosomes using a panel of rat x mouse somatic cell hybrid clones. (ii) Length variation of the STMSs among 8 inbred rat strains could be visualized at 85 of 107 loci examined (79.4%). (iii) A genetic map, integrating biochemical, coat color, mutant and restriction fragment length polymorphism loci, was constructed based on the segregation of 125 polymorphic markers in seven rat backcrosses and in two F2 crosses. Twenty four linkage groups were identified, all of which were assigned to a defined chromosome. As a reflection of the bias for coding sequences in the public data bases, the STMSs described herein are often associated with genes. Hence, the genetic map we report coincides with a gene map. The corresponding map locations of the homologous mouse and human genes are also listed for comparative mapping purposes.

Animals↗

PubMed1992

Confirmation of genetic linkage between atopic IgE responses and chromosome 11q13.

Genetic linkage between atopic IgE responses and chromosome 11q13 (D11S97) has been previously reported in a limited number of extended families. Difficulties of phenotyping in the older family members, poor family structure in some families, and genetic heterogeneity were proposed as possible explanations for the variability in lod scores. To test this finding a second linkage study of 64 young nuclear families was undertaken and gave a two point lod score of 3.8 at theta = 0.07 (assuming theta m = theta f). A test of genetic heterogeneity in the nuclear families shows that atopic IgE responses are linked to this locus in 60 to 100% of families (approximate 95% confidence limits).

Adolescent↗

PubMed1992

Postvenereal Reiter's syndrome in Greenland.

Reiter's syndrome is very frequent in the Inuit of Greenland, because of high frequencies of venereal disease and HLA-B27. The authors report the results of the epidemiologic work and of the study of the effects of antibiotic treatment of venereal infection. In Reiter's syndrome patients, treatment of venereal infections by erythromycin or tetracycline was associated with a significant reduction in the rate of postvenereal arthritic flares.

Anti-Bacterial Agents↗

PubMed1991

Paramyotonia congenita and hyperkalemic periodic paralysis are linked to the adult muscle sodium channel gene.

The hyperkalemic periodic paralyses are a clinically heterogeneous group of autosomal dominant syndromes characterized by episodic paralysis associated with an elevated serum potassium level. Affected individuals in the same family tend to have homogeneous symptom complexes, although phenotypic variation is present among different families. For example, myotonia is absent in some pedigrees, present in others, and, in a third variant, paramyotonia congenita, myotonia coexists with cold-induced paralysis. Electrophysiological studies have demonstrated variant-specific abnormalities in skeletal muscle membrane sodium conductance. We tested the hypothesis that hyperkalemic periodic paralysis (without myotonia) and paramyotonia congenita are tightly linked to the tetrodotoxin-sensitive adult skeletal muscle sodium channel gene on chromosome 17q23-25 in two large pedigrees. The DNA polymorphisms detected in the growth hormone skeletal muscle sodium channel complex (GH1-SCN4A) and by flanking polymorphic markers (D17S74 and D17S40) demonstrated no recombinants between the disease phenotypes and this complex. Phenotypic variation in the hereditary hyperkalemic periodic paralyses may result from allelic heterogeneity at the tetrodotoxin-sensitive adult skeletal muscle sodium channel locus.

Adult↗

PubMed1991

A detailed multipoint map of human chromosome 4 provides evidence for linkage heterogeneity and position-specific recombination rates.

Utilizing the CEPH reference panel and genotypic data for 53 markers, we have constructed a 20-locus multipoint genetic map of human chromosome 4. New RFLPs are reported for four loci. The map integrates a high-resolution genetic map of 4p16 into a continuous map extending to 4q31 and an unlinked cluster of three loci at 4q35. The 20 linked markers form a continuous linkage group of 152 cM in males and 202 cM in females. Likely genetic locations are provided for 25 polymorphic anonymous sequences and 28 gene-specific RFLPs. The map was constructed employing the LINKAGE and CRIMAP computational methodologies to build the multipoint map via a stepwise algorithm. A detailed 10-point map of the 4p16 region constructed from the CEPH panel provides evidence for heterogeneity in the linkage maps constructed from families segregating for Huntington disease (HD). It additionally provides evidence for position-specific recombination frequencies in the telomeric region of 4p.

Chromosome Mapping↗

PubMed1991

Linkage analysis in spinal muscular atrophy, by six closely flanking markers on chromosome 5.

The proximal spinal muscular atrophies (SMA) represent the second most common autosomal recessive disorder, after cystic fibrosis. The gene responsible for chronic SMA has recently been mapped to chromosome 5q by using genetic linkage studies. Among six markers mapping to this region, five were shown to be linked with the SMA locus in 39 chronic SMA families each containing at least two affected individuals. Multilocus analysis by the method of location score was used to establish the best estimate of the SMA gene location. Our data suggest that the most likely location for SMA is between loci D5S6 and D5S39. The genetic distances between these two markers are estimated to be 6.4 cM in males and 11.9 cM in females. Since meiosis were informative with D5S39 and D5S6 in 92% and 87% of SMA families, respectively, it is hoped that the present study will contribute to the calculation of genetic risk in SMA families.

Chromosome Mapping↗

PubMed1990

Gene mapping.

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Chromosome Mapping↗

PubMed1990

Minisatellite linkage maps in the mouse by cross-hybridization with human probes containing tandem repeats.

Tests of 29 human variable number of tandem repeat probes in inbred mouse lines showed that 80% (23/29) cross-hybridize, and 48% (14/29) produce multiple band, minisatellite polymorphisms (fingerprint patterns). Mini-satellite-type polymorphisms detected by 11 probes were characterized in eight different strains; on average, 240 polymorphic differences were detected between pairs of strains. Reproducible fingerprint patterns permit the study of the segregation of the minisatellite polymorphisms in experimentally designed crosses. As an example, we constructed primary minisatellite genetic linkage maps containing 346 polymorphic bands, distributed in 101 groups of closely linked systems, from genotypes on a recombinant inbred panel (C57BL/6J X DBA/2J); 38 of the groups were assigned by linkage to 15 autosomal chromosomes. The minisatellite genetic maps of C57BL/6J and DBA/2J can be applied in other linkage studies involving these strains.

Animals↗

PubMed1990

Simultaneous localization of cosmids and chromosome R-banding by fluorescence microscopy: application to regional mapping of human chromosome 11.

A technique for nonradioactive in situ hybridization on human metaphase chromosomes has been developed to localize human cosmid clones. The simple procedure using two fluorescent dyes (fluorescein and propidium iodide) allows the simultaneous identification of chromosomal R-bands and hybridization signal in a single screening of the slides. This technique has been used for rapid correlation of the genetic and physical map of chromosome 11q13-qter in the region of genes responsible for ataxia-telangiectasia and tuberous sclerosis.

Cell Line↗

PubMed1990

Combined segregation and linkage analysis of genetic hemochromatosis using affection status, serum iron, and HLA.

Characterizing the distribution of parameters of iron metabolism by hemochromatosis genotype remains an important goal vis-à-vis potential screening strategies to identify individuals at genetic risk, since a specific marker to detect the abnormal gene has not been identified as yet. In the present investigation, we analyze serum iron values in ascertained families using a method which incorporates both segregation of the clinical affection status and the HLA linkage information to identify the underlying genotypes. The analysis is performed using an extension of the model presented by Bonney et al., comprising regressive models for segregation analysis and the multipoint linkage strategy implemented in LINKAGE. The gene was found to be completely recessive with respect to both clinical manifestations and serum iron abnormalities, with significant differences in expression by sex. Clinical manifestations were present for all male homozygotes in this data set, suggesting that the recessive hemochromatosis genotype is fully penetrant at all ages in males. This was not the case for younger females. Significant genotype-specific age and sex effects were found for serum iron values. It is interesting that deletion of the HLA marker information did not affect our ability to resolve the genetic model when we analyzed a bivariate phenotype. This serves as a reminder that a search for relevant biological markers can be equally important in discerning the genetic etiology of a disease trait, as a search for linked genetic markers.

Age Factors↗

PubMed1989