PubMed Health⌕ Search

Biomedical subjects

G Tromp

Publications and source records attributed to G Tromp.

At least 37 records · Page 2Linked to original sources
PubMed1996

Multiple defects in type III collagen synthesis are associated with the pathogenesis of abdominal aortic aneurysms.

Confluent skin fibroblast cultures were prepared from 40 patients diagnosed with and surgically treated for an abdominal aortic aneurysm. An analysis of secreted type I and type III collagen in the media of these fibroblast preparations revealed reduced secretion of type III collagen from six patients. DNA sequence analysis of the entire coding domain of the pro alpha 1 (III) collagen mRNA in skin fibroblast RNA from these six patients revealed a C to T substitution at nucleotide 607 in one of the probands that would result in the replacement of a leucine residue with phenylalanine in the second position of the first tripeptide repeat in the triple-helical domain of type III collagen. Allele-specific hybridization analysis of genomic DNA from this proband and family members indicated that this non-glycine substitution probably contributed to the aneurysmal phenotype in this patient. No coding sequence mutations were found in the other five patients. It is clear from this study, therefore, that aberrant synthesis of type III collagen, as a consequence of both a coding sequence mutation and other factors contributing to reduced secretion of type III procollagen, will result in the development of an aortic aneurysm in a significant percentage of patients with this disease.

Age of Onset↗
PubMed1996

Expression of mRNAs for lysyl oxidase and type III procollagen in cultured fibroblasts from patients with the Menkes and occipital horn syndromes as determined by quantitative polymerase chain reaction.

The Menkes syndrome and the occipital horn syndrome are two X-linked recessively inherited disorders characterized by abnormalities in copper metabolism. These abnormalities are associated with a reduction in the activity of lysyl oxidase (EC 1.4.3.13), an extracellular copper enzyme that initiates the crosslinking of collagens and elastin. We report here that the amount of lysyl oxidase mRNA, as studied by Northern blotting, and the number of lysyl oxidase mRNA molecules per picogram of RNA, as determined by a quantitative PCR method, were decreased in three cultured skin fibroblast lines from patients with the Menkes syndrome and two from patients with the occipital horn syndrome compared with four control cell lines. The decreased lysyl oxidase activity found in these disorders thus appears to be a least in part due to a pretranslational mechanism. No decrease was found in the number of the beta-actin mRNA molecules in the Menkes cell lines, but rather a slight increase, whereas a decrease was found in these molecules in the occipital horn cell lines. An additional abnormality found in the Menkes cell lines was a significant increase in the number of mRNA molecules for type III procollagen in two of the three cell lines investigated. The present and previous data indicate that the Menkes syndrome may involve several abnormalities in the expression of genes for connective tissue proteins.

Base Sequence↗
PubMed1996

Substitution of arginine for glycine at position 154 of the alpha 1 chain of type I collagen in a variant of osteogenesis imperfecta: comparison to previous cases with the same mutation.

A substitution of arginine for glycine at amino acid position 154 of the alpha 1(I) collagen chain was found in a father and his three children. The phenotype of the patients includes manifestations of types I and III/IV osteogenesis imperfecta, but appears to be milder than that of the previously described two unrelated patients that had the identical mutation in the alpha 1(I) collagen chain. The variability in the phenotype raises the possibility of epistatic loci or environmental effects on expression of the disorder.

Adult↗
PubMed1996

Direct sequencing of PCR products derived from cDNAs for the pro alpha 1 and pro alpha 2 chains of type I procollagen as a screening method to detect mutations in patients with osteogenesis imperfecta.

More than 150 mutations in the genes for type I procollagen have been found in unrelated patients with osteogenesis imperfecta (OI), but mutations have been difficult to define in many patients with the mildest forms of the disease. Here, we have used robotically automated sequencing of the cDNAs for type I procollagen to screen for mutations in 12 patients suspected of having nonlethal OI (types I, III, and IV). Single base mutations that changed codons for obligate glycine residues were found in seven of the patients. Altogether, we analyzed 4,379 bp of sequences of both alleles of the pro alpha 1 (I) collagen (8,758 bp of allelic sequences) and 4,200 bp of sequences of both alleles of the pro alpha 2(I) collagen (8,400 bp of allelic) from each patient.

Adult↗
PubMed1996

Familial abdominal aortic aneurysms: screening of 71 families.

OBJECTIVE: To find out the local prevalence of familial abdominal aortic aneurysms. DESIGN: Retrospective open study. SETTING: University hospital, Finland. SUBJECTS: 71 families of patients operated on for abdominal aortic aneurysm. INTERVENTIONS: Ultrasound screening, personal interviews and study of population registers, death certificates and hospital records. MAIN OUTCOME MEASURES: The diagnosis of asymptomatic abdominal aortic aneurysms. RESULTS: 148 of the 291 patients operated on replied to our letter (51%). The ultrasound examination was carried out on 123 siblings and detected abdominal aortic aneurysm in one sister (1/78 about 1%) and four brothers (4/45 about 9%). By the other methods data were obtained on 77 siblings (54 men and 23 women) of whom two sisters and six brothers were found to have abdominal aortic aneurysms. When the figures for the 71 families were combined, 10% of the brothers (10/99) and 3% of the sisters (3/101) had abdominal aortic aneurysms. These siblings were from 11 different families and so the prevalence of families with at least two affected persons was 16% (11/71). The index patient in 65 families was male and the prevalence of risk families (with two or more cases of aneurysm) in this group was 15% (10/65). The index case was a woman in six families giving a prevalence of 33% (2/6) (p = 0.2 between the groups). CONCLUSION: The screening of families of patients with abdominal aortic aneurysms should be restricted to the brothers of these patients.

Adult↗
PubMed1996

Genetic linkage of familial granulomatous inflammatory arthritis, skin rash, and uveitis to chromosome 16.

Blau syndrome (MIM 186580), first described in a large, three-generation kindred, is an autosomal, dominantly inherited disease characterized by multiorgan, tissue-specific inflammation. Its clinical phenotype includes granulomatous arthritis, skin rash, and uveitis and probably represents a subtype of a group of clinical entities referred to as "familial granulomatosis." It is the sole human model with recognizably Mendelian inheritance for a variety of multisystem inflammatory diseases affecting a significant percentage of the population. A genomewide search for the Blau susceptibility locus was undertaken after karyotypic analysis revealed no abnormalities. Sixty-two of the 74-member pedigree were genotyped with dinucleotide-repeat markers. Linkage analysis was performed under a dominant model of inheritance with reduced penetrance. The marker D16S298 gave a maximum LOD score of 3.75 at theta = .04, with two-point analysis. LOD scores for flanking markers were consistent and placed the Blau susceptibility locus within the 16p12-q21 interval.

Adolescent↗
PubMed1995

Quantitative polymerase chain reaction of lysyl oxidase mRNA in malignantly transformed human cell lines demonstrates that their low lysyl oxidase activity is due to low quantities of its mRNA and low levels of transcription of the respective gene.

Lysyl oxidase (EC 1.4.3.13), an extracellular copper amino oxidase, initiates the cross-linking of collagens and elastin by catalyzing oxidative deamination of the epsilon-amino group in certain lysine and hydroxylysine residues. We developed here a polymerase chain reaction (PCR) method for the quantification of lysyl oxidase mRNA in which a synthetic RNA is used as an internal standard for coamplification with the targeted mRNA. The amount of lysyl oxidase mRNA when studied by Northern blot analysis and the number of lysyl oxidase mRNA molecules when determined by the quantitative PCR method were found to be markedly low in various malignantly transformed cell lines relative to control cell lines, quantitative PCR indicating values of about 2-10% of those in the controls. No difference was found in the number of beta-actin mRNA molecules between the transformed cells and the controls. Nuclear runoff experiments indicated that most if not all of the decrease in the number of lysyl oxidase mRNA molecules can be explained by diminished transcription of the respective gene.

Adult↗
PubMed1995

Aberrant splicing of the type III procollagen mRNA leads to intracellular degradation of the protein in a patient with Ehlers-Danlos type IV.

Ehlers-Danlos syndrome type IV (EDS IV) is an autosomal dominant disorder characterized by fragile skin, blood vessels, and internal organs and associated with decreased production, secretion, or thermal stability of type III procollagen. Mutations in the gene for type III procollagen have been identified in patients exhibiting decreased secretion or thermal stability of the protein, but no defect has been elucidated to explain the decreased production of type III procollagen in some patients with EDS IV. We report on a patient with a moderate case of EDS IV who produced decreased amounts of type III procollagen despite normal levels of translatable type III procollagen mRNA. S1 nuclease analysis of the type III procollagen mRNA indicated a defect in the region encoding exon 27. Sequence analysis of cDNA clones and genomic fragments generated by polymerase chain reaction amplification revealed that sequences encoded by exon 27 were absent from 3 out of 5 cDNA clones and that a G at the +5 position of the splice donor site in intron 27 was changed to an A in one allele of the patient's type III procollagen gene. Using a cDNA-genomic DNA hybrid probe in S1 nuclease analysis, fragments consistent with mRNA species containing and lacking exon 27 were detected in a 1:1 ratio. Pulse label and chase experiments in the presence or absence of brefeldin A indicated that most of the type III procollagen molecules synthesized by the patient's fibroblasts were not secreted into the medium but were degraded in the endoplasmic reticulum-Golgi compartment by a nonlysosomal mechanism.

Adult↗
PubMed1995

Ehlers-Danlos syndrome type IV: a single base substitution of the last nucleotide of exon 34 in COL3A1 leads to exon skipping.

The Ehlers-Danlos syndrome has been classified into nine phenotypic presentations. Type IV is a variant of particular importance because people affected with this genodermatosis are at great risk of spontaneous hemorrhage from vascular rupture or bowel perforation. Recent molecular advances have identified mutations in the gene for type III procollagen as responsible for Ehlers-Danlos syndrome type IV. We report a case of a 14-year-old male with a typical presentation of the type IV variant who was found to have markedly dilated fibroblast cisternae and varying collagen fibril diameter on ultrastructural study. A novel genetic defect was noted by polymerase chain reaction and DNA sequencing of genetic material isolated from skin fibroblast cultures. Analysis of the gene for type III procollagen revealed a single base mutation in the last nucleotide of exon 34. The mutation led to abnormal RNA splicing and skipping of exon 34 on the mRNA level.

Adolescent↗
PubMed1995

Special features of familial intracranial aneurysms: report of 215 familial aneurysms.

FAMILIAL INTRACRANIAL ANEURYSMS (FIAs) were compared with nonfamilial aneurysms (non-FIAs); the study group from east Finland included 167 family members from 85 families with FIAs. In every family, there has been two or more proven cases of subarachnoid hemorrhages among first-degree family members. Two-hundred and fifteen FIAs were found. The patients with FIAs were younger, and their aneurysms were smaller. Half of the FIAs were on the middle cerebral artery (n = 106 of 215), preferentially on the right side. Nearly one-third of the ruptured FIAs were smaller than 6 mm, and more than 80% of the aneurysms were under 14 mm in diameter. There were no significant differences between the frequency of aneurysms at mirror sites in FIA and non-FIA groups. Among siblings with FIAs, the frequency of pairs with age at onset within 10 years of each other was more than twice that expected from randomly selected pairs in the non-FIA group.

Adult↗
PubMed1995

DNA-based diagnostics in the study of heritable and acquired disorders.

Recent advances in molecular biology techniques have made DNA diagnostics a reality. A major advance was the development of the polymerase chain reaction, which allows the direct analysis of a region of a known gene from minute quantities of template DNA. The DNA can even be isolated from such sources as saliva, hair roots, microscope slides, paraffin-embedded tissue, and clinical swabs, in addition to blood and biopsy material. Another major improvement is the development of automated procedures suitable for robotic stations. Together these improvements make DNA analysis an important part of diagnostic procedures in studying the etiology of diseases.

Animals↗
PubMed1994

Molecular basis of osteogenesis imperfecta and related disorders of bone.

Recent work has demonstrated that more than 90% of patients with osteogenesis imperfecta (OI) have mutations in the gene for either the pro alpha 1 (I) chain or the gene for the pro alpha 2 (I) chain of type I procollagen. Three molecular mechanisms have explained the devastating effects of these mutations. In addition, the data provide several general conclusions about mutations in collagen genes. Studies in cell cultures with antisense oligonucleotides and studies in transgenic mice with an antisense gene raised the possibility that several strategies eventually may be developed to treat OI by converting severe forms of the disease to milder forms.

Animals↗
PubMed1994

Robotic automation of dideoxyribonucleotide sequencing reactions.

We developed a robot to carry out standard Sanger dideoxyribonucleotide sequencing reactions efficiently and with minimal human intervention. A commercial robot was adapted to our design and specifications, and we programmed it to perform up to 240 sequencing reactions in a single unattended run of 7 h. The robot configuration can be easily altered to allow 480 reactions to be performed in an unattended run of 14 h. The special features of our robot include cooled reagent reservoirs and cooled chambers for storage of DNA templates and completed reactions as well as reproducible aspiration of small volumes by using a sensing algorithm. The robot has successfully performed over 3500 DNA reactions in about 30 separate runs in our DNA core facility.

DNA-Directed DNA Polymerase↗
PubMed1993

Single base mutation that substitutes glutamic acid for glycine 1021 in the COL3A1 gene and causes Ehlers-Danlos syndrome type IV.

The proposita described here was a 24-year-old woman with an acrogeric form of the Ehlers-Danlos syndrome including a massive dissecting aortic aneurysm. She was found to have a single-base mutation that substituted glutamic acid for glycine at amino acid position 1021 in the triple-helical domain of the type III procollagen. It is the most carboxy-terminal single-base mutation characterized to date in the COL3A1 gene. Analysis of medium and cell layer proteins from proposita's cultured skin fibroblasts showed that the mutant protein was poorly secreted, migrated more slowly on a polyacrylamide gel, and was partially unstable at +25 degrees C to brief digestion with trypsin.

Adult↗
PubMed1993

Temperature sensitivity of aberrant RNA splicing with a mutation in the G+5 position of intron 37 of the gene for type III procollagen from a patient with Ehlers-Danlos syndrome type IV.

A single-base mutation in intron 37 of the gene for type III procollagen (COL3A1) was found in a proband with the type IV variant of Ehlers-Danlos syndrome. Probe-protection experiments with S1 nuclease and RNA from fibroblasts incubated at 37 degrees C demonstrated that about 35% of the total mRNA or about 70% of the mRNA from mutated allele was spliced by exon skipping. The effects of the mutation were temperature-sensitive in that the amount of RNA from the mutated allele that was spliced by exon skipping was 87.1 +/- 7.7% at 31 degrees C, 70.1 +/- 6.5% at 37 degrees C, and 85.4 +/- 11.1% at 42 degrees C. The effects of temperature on aberrant RNA splicing were, therefore, the reverse of those reported for four previous mutants in collagen genes. The increase in abnormal RNA splicing when the temperature was raised from 31 degrees to 37 degrees C seen with previously reported mutants suggested that RNA-RNA hybridization of U1snRNA to the 5'-splice site in the substrate may be limiting in the processing of transcripts from the mutated alleles, since RNA-RNA hybridizations become less favorable at higher temperatures. The decrease in abnormal RNA splicing seen here when the temperature was raised from 31 degrees to 37 degrees C suggested that protein-RNA or protein-protein binding steps become rate limiting with the G+5 mutation in intron 37 of the COL3A1 gene.

Adolescent↗