Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012872 (DNA marker)
 929 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The search for the Huntington's disease (HD) gene has prompted construction of a complete long-range restriction map of a 2.5-Mb candidate region, distal to the DNA marker D4S10. To facilitate the procurement of cloned DNA from this candidate region, we have augmented the existing regional mapping panel of somatic cell hybrids with hybrid HHW1071 containing a t(4p16;12) chromosome from a patient with Wolf-Hirschhorn syndrome. This translocation maps between D4S180 and D4S127, subdividing the HD candidate region and setting a proximal limit to the Wolf-Hirschhorn syndrome region. Using the expanded mapping panel, we have regionally assigned 14 independently cloned cosmids, five proximal to the t(4;12) breakpoint in the same region as D4S10 and nine distal to the breakpoint. By a combination of overlap with previously mapped cosmids and pulsed-field gel analysis, each of these cosmids has been positioned on the long-range restriction map of 4p16.3, increasing the clone coverage of the candidate region to approximately 40%. Single-copy probes from mapped cosmids were used to identify eight new DNA polymorphisms spanning the HD candidate region. These new DNA markers should prove valuable for analysis of recombination and linkage disequilibrium in HD, as well as for preclinical diagnosis of the disorder.
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PMID:New DNA markers in the Huntington's disease gene candidate region. 168 79

The DNA marker locus D21S13, localized in the 21q11.1-q21 region, has been closely linked to familial Alzheimer's disease. We constructed a physical map of 1.7 Mb around D21S13 using probes pGSM21 and pGSE9. The results indicated that pGSM21 contains recognition sites for at least three rare-cutting restriction enzymes. The clustering of rare-cutting restriction sites is indicative of the presence of an HTF (HpaII tiny fragment) island. Restriction site mapping and methylation analysis proved that pGSM21 contains a methylation-free HTF island. Furthermore, a cDNA correlate has been isolated confirming that pGSM21 is part of an expressed sequence. Today, the gene associated with pGSM21 is the gene closest to the centromere on the 21q arm.
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PMID:The pericentromeric 21 DNA marker pGSM21 (D21S13) contains an expressed HTF island. 169 97

The polymorphic DNA marker D20S14 was previously mapped to human chromosome 20 and shown to be linked to two other DNA markers, D20S5 and D20S6, located at 20p12. This segment has been implicated in several human diseases. Because of its importance, we mapped the D20S14 locus to 20p12----p11.2 by radioactive in situ hybridization.
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PMID:The polymorphic DNA sequence D20S14 is assigned to human chromosome 20p12----p11.2 by in situ hybridization. 173 66

The long-QT syndrome (LQT; Ward-Romano syndrome) is a cardiac disorder that is inherited as an autosomal dominant trait. Affected family members suffer from recurrent syncope and sudden death due to ventricular arrhythmias. Recently, we identified a DNA marker on the short arm of chromosome 11 (the Harvey ras-1 locus [H-ras-1]) that was completely linked to the LQT locus in one large family. In the study presented here, we performed linkage investigations on six new and unrelated families with LQT. The LQT locus was again completely linked to the H-ras-1 locus in all families examined, with a combined lod score of 5.25 at a recombination fraction of 0. This work confirms our previous assignment of the LQT locus to chromosome 11p and supports the hypothesis that LQT is genetically homogeneous. As no obligate recombinants were identified in either this or our previous study, the H-ras-1 protooncogene remains a candidate for the LQT disease gene. Identification of LQT families with locus homogeneity is an important step in the development of a refined genetic map of this locus and will help determine whether the H-ras-1 marker would be of general use for presymptomatic diagnosis of this potentially fatal, but treatable, disorder.
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PMID:Consistent linkage of the long-QT syndrome to the Harvey ras-1 locus on chromosome 11. 174 60

Screening purpose-built libraries with minisatellite probes, we have isolated 36 bovine variable number of tandem repeat markers (VNTRs) characterized by a mean heterozygosity of 59.3 within the American Holstein breed. Matching probabilities and exclusion powers were estimated by Monte-Carlo simulation, showing that the top 5 to 10 markers could be used as a very efficient DNA-based system for individual identification and paternity diagnosis. The isolated VNTR systems should contribute significantly to the establishment of a bovine primary DNA marker map. Linkage analysis, use of somatic cell hybrids, and in situ hybridization demonstrate that these bovine VNTRs are scattered throughout the bovine genome, without evidence for proterminal confinement as in the human, and that at least some of them are organized as clusters. Moreover, Southern blot analysis and in situ hybridization demonstrate conservation of sequence and map location of minisatellites within Bovidae.
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PMID:Characterization of a set of variable number of tandem repeat markers conserved in bovidae. 176 84

Cystic fibrosis (CF) screening by measurement of immunoreactive trypsin (IRT) lacks specificity: only 9% of hypertrypsinemic neonates have CF. We have studied retrospectively 114 hypertrypsinemic samples (including 37 CF) for KM.19 polymorphic DNA marker and made risk calculations. If the neonate is homozygous for KM.19 allele 2, the risk of CF rises to 55%; if homozygous for allele 1, the risk is very low (less than 1%) and if heterozygous, the risk is intermediate (4%). In a prospective study including 28,000 IRT tests, 76 neonates with IRT greater than 800 micrograms/L have been identified: 16 were homozygous for allele 2 (8 CF), 30 for allele 1 (1 CF), and 30 were heterozygotes (no CF). Deletion 508 was present in 10 neonates: 4 homozygotes (4 CF) and 6 heterozygotes (3 CF). Two CF did not carry any copy of deletion 508. We have studied 181 (presumably non-CF) neonates with IRT greater than 600 micrograms/L. The KM.19 genotypes distribution is significantly different from the one expected in the French population: homozygotes for allele 2 are more numerous. Furthermore, heterozygotes for deletion 508 are 1 in 15 (expected: 1 in 42). In conclusion, molecular biology in dried blood spots can enhance the specificity of CF neonatal screening, but IRT and genotype may not be independent.
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PMID:The application of PCR amplification and the polymorphic marker KM.19 to dried blood spots: comparison with deletion 508 for the confirmation of the neonatal screening test for cystic fibrosis. 178 24

To assess the association between recombination and nondisjunction of chromosome 21, we analyzed cytogenetic and DNA markers in 104 trisomy 21 individuals and their parents. Our DNA marker studies of parental origin were informative in 100 cases, with the overwhelming majority (94) being maternal in origin. This value is significantly higher than the 75%-80% maternal nondisjunction rate typically observed in cytogenetic studies of trisomy 21 and illustrates the increased accuracy of the molecular approach. Using the maternally derived cases and probing at 19 polymorphic sites on chromosome 21, we created a genetic map that spans most of the long arm of chromosome 21. The map was significantly shorter than the normal female linkage map, indicating that absence of pairing and/or recombination contributes to nondisjunction in a substantial proportion of cases of trisomy 21.
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PMID:Trisomy 21: association between reduced recombination and nondisjunction. 153

The von Recklinghausen neurofibromatosis (NF1) gene has been mapped to the pericentromeric region of chromosome 17 and various DNA markers have been identified in this region. We have performed a genetic analysis using an anonymous DNA marker, HHH202 (D17S33), tightly linked to the NF1 gene in seven NF1 Italian families. Only one family was fully informative for the HHH202/RsaI polymorphism. In this family this marker can be used for presymptomatic and prenatal diagnosis. However, it is necessary to use additional flanking markers in order to increase informativeness and to obtain better diagnostic accuracy.
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PMID:Molecular study in von Recklinghausen neurofibromatosis (NF1). 190 26

We describe 9-year-old twin girls who were thought to be monozygotic but who differed greatly in physical appearance and growth pattern. One twin had Ullrich-Turner syndrome (UTS), 45,X/46,XX mosaicism in peripheral blood, and only 45,X cells in skin fibroblasts. The phenotypically normal twin also had 45,X/46,XX mosaicism in blood but only 46,XX cells in cultured fibroblasts. Analysis of DNA marker patterns in blood lymphocytes and in skin fibroblasts confirmed monozygosity with a probability of 99.97%. This case is compared with other reported cases of discordance for UTS in twins. It is concluded that essentially all of the differences between the two twins can be explained by loss of an X chromosome early in embryogenesis with complete separation of 45,X and 46,XX cell lineages at the time of the twinning event. The presence of mosaicism in the peripheral blood of both twins is presumably due to anastomoses between the placentae resulting in a mixture of the two cell populations in the hematopoietic tissue.
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PMID:Monozygotic twins discordant for Ullrich-Turner syndrome. 195 67

The polymorphic DNA marker DXS304 detected by probe U6.2 has recently been shown to be closer to the fragile X locus than previously available markers. Its usefulness has however been limited by its relatively low heterozygosity. We have isolated, by cosmid cloning, a 67 kilobase region around probe U6.2 and have characterized a new probe (U6.2-20E) that detects BanI and BstEII restriction fragment length polymorphisms (RFLPs). The BanI RFLP has a heterozygosity of 0.49 and is in partial linkage disequilibrium with the previously described polymorphism, with a combined heterozygosity of 0.63. Furthermore, we have found that the U6.2 original probe, which probably detects an insertion-deletion polymorphism, is also informative in BanI digests. Thus, the two informative RFLPs at the DXS304 locus can be conveniently tested in a single hybridization with a single digest. An updated linkage analysis confirms that DXS304 is distal to the fragile X locus. This informative locus can now be used effectively for genetic mapping of the Xq27-q28 region, and for diagnostic applications in fragile X or Hunter syndrome families.
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PMID:New informative polymorphism at the DXS304 locus, a close distal marker for the fragile X locus. 196 34


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