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J L Weber

Publications and source records attributed to J L Weber.

At least 91 records · Page 5Linked to original sources
PubMed1993

Genetic and physical map of 11 short tandem repeat polymorphisms on human chromosome 6.

A linkage map of 11 short tandem repeat polymorphisms was constructed for human chromosome 6. The order from p to qter was F13A1-D6S105-D6S254-D6S251-D6S252-D6S24 9-(ARG1-D6S87)-D6S250-D6S255-D6S253. For the region spanned by the 6q markers, the male map distance was less than half the female map distance (58 and 126.3 cM, respectively). Two-point linkage analysis was also used to position the markers relative to markers in the CEPH public database. Physical mapping of these markers was completed using a somatic cell hybrid panel that contained varying segments of chromosome 6. Two of the markers mapped to the short arm of chromosome 6; the remainder were spaced over 86.5 cM of the long arm from 6q13 to 6qter. The linkage and physical maps were completely consistent.

Base Sequence↗
PubMed1993

A PCR-based linkage map of human chromosome 1.

A genetic linkage map of human chromosome 1 based entirely on PCR-typable markers has been developed using 38 simple sequence repeat (SSR) polymorphisms. These SSRs include 36 dinucleotide repeats and 2 tetranucleotide repeats. The average heterozygosity at these markers was 0.73 and ranged from 0.52 to 0.95. Multipoint linkage analysis was used to develop a map of these 38 markers in which the relative placement of each locus is supported by likelihood odds > 1000:1. This PCR-based map was anchored at the centromere by the D1Z5 alpha-satellite polymorphism, and the ends of the map were defined by D1Z2 and D1S68, which are the most distal loci in the CEPH consortium map of chromosome 1. The sex-averaged, male, and female maps extend for 328, 273, and 409 cM, respectively. The average distance between markers on the sex-averaged map is 8 cM, and the largest interval is 32 cM. This map of highly informative PCR-based markers will provide a rapid means of screening human chromosome 1 for the presence of disease genes.

Base Sequence↗
PubMed1993

A continuous linkage map of 22 short tandem repeat polymorphisms on human chromosome 12.

A continuous linkage map consisting of 22 short tandem repeat polymorphisms has been constructed for human chromosome 12 using 23 non-CEPH pedigrees. The markers were distributed at an average distance of 9.35 cM (3.1-33.9 cM). Eighteen of the markers could be positioned uniquely with a likelihood of > 1000:1. The physical locations of some of the markers suggest that the map covers 85-95% of the chromosome. This framework map of 18 markers has a female length of 213 cM and a male length of 131 cM. Female recombination frequencies were greater than male recombination frequencies except in the distal portion of the short arm. The map provides confirmatory evidence for orders established previously on CEPH pedigrees and uniquely positions 4 additional markers (CD4, ATPSB, D12S56, PLA2).

Chromosome Mapping↗
PubMed1993

Genetic linkage of mild pseudoachondroplasia (PSACH) to markers in the pericentromeric region of chromosome 19.

Pseudoachondroplasia (PSACH) is a dominantly inherited form of short-limb dwarfism characterized by dysplastic changes in the spine, epiphyses, and metaphyses and early onset osteoarthropathy. Chondrocytes from affected individuals accumulate an unusual appearing material in the rough endoplasmic reticulum, which has led to the hypothesis that a structural abnormality in a cartilage-specific protein produces the phenotype. We recently identified a large family with a mild form of pseudoachondroplasia. By genetic linkage to a dinucleotide repeat polymorphic marker (D19S199), we have localized the disease gene to chromosome 19 (maximum lod score of 7.09 at a recombination fraction of 0.03). Analysis of additional markers and recombinants between the linked markers and the phenotype suggests that the disease gene resides within a 6.3-cM interval in the immediate pericentromeric region of the chromosome.

Achondroplasia↗
PubMed1993

Assignment of a gene locus involved in craniosynostosis to chromosome 5qter.

Craniosynostosis, the abnormal development of the calvarial sutures, occurs as an autosomal dominant trait in many clinically distinct syndromes. We performed linkage analysis of a provisionally novel type of autosomal dominant craniosynostosis in a large three generational family. Linkage was established between the craniosynostotic locus and D5S211, a locus defined by the short tandem repeat polymorphism (STRP) marker Mfd 154 in distal 5q. The maximum LOD score, Zmax, was 4.8 at a recombination fraction of zero. No significant linkage was found with markers located 30 cM and more proximal to D5S211. The findings assign the craniosynostotic locus in this family to a telomeric region in the long arm of chromosome 5. Linkage analysis with Mfd 154 in other autosomal dominant craniosynostotic syndromes should reveal whether these disorders are caused by mutations of genes at the same or at different loci.

Adult↗
PubMed1993

Autosomal dominant supravalvular aortic stenosis: localization to chromosome 7.

Supravalvular aortic stenosis (SVAS) is a localized or diffuse congenital narrowing of the ascending aorta which may occur sporadically, as a familial defect, or in association with Williams syndrome. Familial cases suggest an autosomal dominant gene defect but the underlying molecular basis of SVAS is unknown. In this study, we sought to localize the genetic defect in familial SVAS by linkage analysis in a large three generation family. A total of 44 polymorphic markers were examined for linkage, including 17 Southern blot-based RFLPs, 2 PCR-based RFLPs, and 25 microsatellites, primarily of the (CA)n repeat type. We report linkage of the disease phenotype to a highly informative (CA)n repeat marker, Mfd 50, at locus D7S440 which has been localized to chromosome arm 7q. Using a 100% penetrance model, which was more conservative than lower values of penetrance, a peak LOD score of 4.66 at a recombination frequency of 0.043 was found. A number of candidate genes have been localized to this region, including collagen 1A2, laminin B1, and elastin. Based on our preliminary linkage data, the abnormal microscopic appearance of aortic elastic fibers in SVAS, and analogous animal and human diseases associated with elastic fiber and vascular abnormalities, there is indirect evidence suggesting elastin as a possible candidate gene for this disorder.

Aortic Valve Stenosis↗
PubMed1993

A microsatellite-based index map of human chromosome 11.

We have constructed a continuous index map of 25 microsatellite markers on human chromosome 11. The markers have been typed in 40 CEPH families, have heterozygosities of 69% or higher and can be typed by PCR. The odds against inversion of adjacent marker loci order are at least 10(5):1. The sex average map covers a total of 162 cM with no gap exceeding 15 cM. Total lengths for female and male maps are 205 and 123 cM, respectively. By use of a hybrid cell panel or by in situ hybridization, 16 of the markers have also been mapped cytogenetically, providing a good correlation of the index map with the cytogenetic map. The map will facilitate high resolution mapping of additional polymorphic loci and of disease genes on chromosome 11.

Chromosome Mapping↗
PubMed1993

Mutation of human short tandem repeats.

A total of 20,000 parent-offspring transfers of alleles were examined through the genotyping within 40 CEPH reference families of 28 short tandem repeat polymorphisms (STRPs) located on chromosome 19. Forty-seven initial mutation events were detected in the STRPs using DNA from transformed lymphoblastoid cell lines, but less than half (39%) could be verified using DNA from untransformed cells. None of the cases where three alleles were observed in a single individual could be verified using DNA from untransformed cells. The average mutation rate for the chromosome 19 STRPs after correction for events which would not be detectable as Mendelian errors was 1.2 x 10(-3) per locus per gamete per generation. This rate may have been inflated by somatic as opposed to germline events. Observed mutation rates for individual STRPs ranged from 0 to 8 x 10(-3). The average mutation rate for tetranucleotide STRPs was nearly four times higher than the average rate for dinucleotide STRPs. For determination of the mode of mutation, events involving STRPs on other chromosomes were also examined. Of the events which were verified using DNA from untransformed lymphocytes or which were likely among those for which DNA from untransformed cells was not available: none were located at the sites of meiotic recombination, 91% involved the gain or loss of a single repeat unit, and 15 occurred in the male germline compared to 4 in the female germline (p = 0.01).

Base Sequence↗
PubMed1993

Second polar body incorporation into a blastomere results in 46,XX/69,XXX mixoploidy.

A case of 46,XX/69,XXX mixoploidy is described. The patient had a normal 46,XX diploid karyotype in lymphocytes but a triploid 69,XXX cell line in most of her fibroblasts. In order to learn more about the underlying mechanism resulting in mixoploidy, we studied short tandem repeat polymorphisms (STRPs) in lymphocyte DNA of the patient's parents and in both lymphocyte and fibroblast DNA of the proband. The findings showed maternal origin of the supernumerary chromosome complement and are best explained by second polar body incorporation into a blastomere.

Abnormalities, Multiple↗
PubMed1993

Confirmation of chromosome 9p linkage in familial melanoma.

Malignant melanoma occurs as a familial cancer in 5%-10% of cases where it segregates in a manner consistent with autosomal dominant inheritance. Evidence from cytogenetics, fine-mapping studies of deletions in melanomas, and recent linkage studies supports the location of a human melanoma predisposition gene on the short arm of chromosome 9. We have carried out linkage analysis using the 9p markers IFNA and D9S126 in 26 Australian melanoma kindreds. Multipoint analysis gave a peak lod score of 4.43, 15 cM centromeric to D9S126, although a lod score of 4.13 was also found 15 cM telomeric of IFNA. These data confirm the existence of a melanoma susceptibility gene on 9p and indicate that this locus most probably lies outside of the IFNA-D9S126 interval. No significant heterogeneity was found between families, when either pairwise or multipoint data were analyzed using HOMOG.

Adult↗
PubMed1993

Evidence for human meiotic recombination interference obtained through construction of a short tandem repeat-polymorphism linkage map of chromosome 19.

An improved linkage map for human chromosome 19 containing 35 short tandem repeat polymorphisms (STRPs) and one VNTR (D19S20) was constructed. The map included 12 new (GATA)n tetranucleotide STRPs. Although total lengths of the male (114 cM) and female (128 cM) maps were similar, at both ends of the chromosome male recombination exceeded female recombination, while in the interior portion of the map female recombination was in excess. Cosmid clones containing the STRP sequences were identified and were positioned along the chromosome by fluorescent in situ hybridization. Four rounds of careful checking and removal of genotyping errors allowed biologically relevant conclusions to be made concerning the numbers and distributions of recombination events on chromosome 19. The average numbers of recombinations per chromosome matched closely the lengths of the genetic maps computed by using the program CRIMAP. Significant numbers of chromosomes with zero, one, two, or three recombinations were detected as products of both female and male meioses. On the basis of the total number of observed pairs of recombination events in which only a single informative marker was situated between the two recombinations, a maximal estimate for the rate of meiotic STRP "gene" conversion without recombination was calculated as 3 x 10(-4)/meiosis. For distances up to 30 cM between recombinations, many fewer chromosomes which had undergone exactly two recombinations were observed than were expected on the basis of the assumption of independent recombination locations. This strong new evidence for human meiotic interference will help to improve the accuracy of interpretation of clinical DNA test results involving polymorphisms flanking a genetic abnormality.

Base Sequence↗
PubMed1993

Linkage analysis in Dutch familial atypical multiple mole-melanoma (FAMMM) syndrome families. Effect of naevus count.

Familial atypical multiple mole-melanoma (FAMMM) syndrome is characterized by the familial occurrence of malignant melanoma of the skin in combination with multiple atypical precursor naevi. In the present study we performed linkage analysis in seven Dutch FAMMM families to define the relationship between the ultimate phenotype melanoma and the postulated precursors, atypical (dysplastic) naevi. Various models were defined, varying from melanoma only to various combinations of melanoma and atypical naevi, reflecting the FAMMM phenotype. Using 124 microsatellite markers spread across all autosomes, hints for linkage were obtained between several chromosome 9p markers and a melanoma locus (D9S171; odds for linkage, 275:1). In a model including melanoma and a florid manifestation of atypical naevi a considerably higher lod score was obtained with D9S171 (odds for linkage, 4365:1); models including milder manifestations yielded less support. We conclude that, also in the Dutch FAMMM families, a melanoma gene is located on the short arm of chromosome 9 and that multiple atypical naevi, at least in certain cases, seems to be a component of the FAMMM phenotype.

Adult↗
PubMed1993

[Mid-term results of balloon percutaneous valvuloplasty in the treatment of aortic valve stenosis in children and adolescents].

Fourteen consecutive patients aged 10.2 +/- 4.2 years with congenital valvular aortic stenosis underwent percutaneous balloon aortic valvuloplasty (PBAV) which reduced the peak-to-peak LV-aortic pressure gradient from 81.2 +/- 16.7 mmHg to 27.5 +/- 12.5 mmHg and the maximal instantaneous Doppler gradient (Dopp G) from 70.0 +/- 13.4 mmHg to 31.4 +/- 12.3 mmHg. These 14 patients were followed up 3.6 +/- 1.1 years after PBAV. Control Doppler examination showed the Dopp G (34.8 +/- 15.4 mmHg) to be comparable to that measured just after PBAV (31.4 +/- 12.3 mmHg). One patient, the only one with a mediocre, immediate result, had to be operated 5.5 years after PBAV. Aortic regurgitation was observed on aortography before PBAV in 10 patients: it remained unchanged in 7 and was aggravated in 3 patients. Aortic regurgitation was observed for the first time after PBAV in 3 patients. At control Doppler examination, aortic regurgitation was present on color Doppler in all cases but was mild or minimal in 9 cases. In one patient, secondary aggravation of aortic regurgitation required aortic valve replacement (homograft) 3 years after PBAV. Four of the 16 PBAV (25%) were performed in these 14 patients were complicated by a femoral arterial thrombosis. This study shows that the good primary results of PBAV in the treatment of congenital valvular aortic stenosis in childhood and adolescence, are maintained at medium-term. The risk of creating severe aortic regurgitation is not completely negligible but does not seem to be out of proportion compared with surgical valvotomy.

Adolescent↗
PubMed1992

Genetic linkage evidence for a familial Alzheimer's disease locus on chromosome 14.

Linkage analysis was used to search the genome for chromosomal regions harboring familial Alzheimer's disease genes. Markers on chromosome 14 gave highly significant positive lod scores in early-onset non-Volga German kindreds; a Zmax of 9.15 (theta = 0.01) was obtained with the marker D14S43 at 14q24.3. One early-onset family yielded a lod score of 4.89 (theta = 0.0). When no assumptions were made about age-dependent penetrance, significant results were still obtained (Zmax = 5.94, theta = 0.0), despite the loss of power to detect linkage under these conditions. Results for the Volga German families were either negative or nonsignificant for markers in this region. Thus, evidence indicates a familial Alzheimer's disease locus on chromosome 14.

Alzheimer Disease↗
PubMed1992

Continuous linkage map of human chromosome 14 short tandem repeat polymorphisms.

Nine moderately to highly informative short tandem repeat polymorphisms were assigned to chromosome 14 using somatic cell hybrids and were mapped using linkage analysis. The nine markers formed a continuous linkage map covering almost the entire long arm from 14q11.2 to q32. The markers filled a large gap within previously reported linkage maps for this chromosome. Best order of the new loci from q11.2 to q32 was D14S50, D14S54, D14S49, D14S47, D14S52, D14S53, D14S55, D14S48, and D14S51. The order shown for all adjacent pairs of loci was very strongly favored with the exception of loci pair D14S55 and D14S48, for which the order was moderately favored. Map lengths for the nine loci were 142 cM in females and 72 cM in males. Female recombination frequencies exceeded male recombination frequencies in the middle and distal portions of the map.

Alleles↗
PubMed1992

North Carolina macular dystrophy is assigned to chromosome 6.

North Carolina macular dystrophy (NCMD) is an autosomal dominant macular dystrophy causing impaired central vision at an early age, is completely penetrant, and is present in a single large family. With the development of the hypervariable microsatellite (CA repeats) markers in the human genome, it was possible to relatively rapidly screen most of the genome for linkage to the NCMD gene. After utilizing 124 genetic markers, which excluded over 95% of the human genome, three Marshfield microsatellites located at 6q13-q21 were linked to the NCMD locus. Marshfield marker (MFD) 131 gave a lod score of Z(theta) = 4.36 at theta = 0.137; MFD 171 gave a Z(theta) = 8.42 at theta = 0.004; and MFD 97 gave a Z(theta) = 13.10 at theta = 0.017. Other retinal diseases have been reported on 6q stressing the importance of this region and possibly suggesting that these diseases may be allelic or located in part of a large macular gene family. Locating and characterizing the NCMD gene may be an important step in understanding this group of maculopathies as well as age-related macular degeneration (AMD), a common cause of blindness in the elderly.

Adult↗