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Biomedical subjects

E Bakker

Publications and source records attributed to E Bakker.

At least 19 recordsLinked to original sources
PubMed1992

Diagnosis of Duchenne and Becker muscular dystrophies by polymerase chain reaction. A multicenter study.

OBJECTIVE--To assess the efficiency, reliability, and ease of use of DNA diagnosis for Duchenne and Becker muscular dystrophies (DMD/BMD) using the polymerase chain reaction (PCR). DESIGN--DNA from the patients was screened for deletion mutations using multiplex PCR, and the results were compared with those obtained by Southern blot analysis. The PCR multiplex reaction detects nine specific "hot-spot" exons in the dystrophin gene while the Southern analysis detects 66 specific dystrophin gene restriction fragments. The multiplex reaction requires 50-fold less DNA than Southern analysis and thus is considerably more sensitive. SETTING--Fourteen university-affiliated and private genetic disease diagnostic laboratories. PATIENTS--Male patients with clinical signs of DMD/BMD. Cases were selected for analysis randomly, without knowledge of whether a deletion was present within the dystrophin gene. MAIN OUTCOME MEASURES--The percentage of cases that were detectable by multiplex PCR in comparison with Southern analysis, the frequency, extent, and location of the detected deletion mutations. In some cases, duplication mutations were monitored. RESULTS--The accuracy of a single PCR multiplex amplification (nine exons) was compared with Southern analysis with 10 cDNA probes that cover the full length of the gene. The multiplex PCR analytic method detected 82% of those deletions detected by Southern analysis methods. In one of 745 analyses, the multiplex method suggested a single exon deletion, which was not confirmed by Southern analysis, representing a false-positive rate of 0.013%. CONCLUSIONS--Multiplex PCR represents a sensitive and accurate method for deletion detection of 46% of all cases of DMD/BMD. The method requires 1 day for analysis, is easy to perform, and does not use radioactive tracers. As such, multiplex PCR represents an efficient and rapid method for prenatal or postnatal diagnosis of DMD/BMD.

Blotting, Southern↗
PubMed1992

Different positively charged amino acids have similar effects on the topology of a polytopic transmembrane protein in Escherichia coli.

Integral membrane proteins from a wide variety of sources conform to a "positive-inside rule," with many more positively charged amino acids in their cytoplasmic as compared to extracytoplasmic domains. A growing body of experimental work also points to positively charged residues in regions flanking the apolar transmembrane segments as being the main topological determinants. In this paper, we report a systematic comparison of the effects of positively (Arg, Lys, His) as well as negatively (Asp, Glu) charged residues on the membrane topology of a model Escherichia coli inner membrane protein. Our results show that positive charge is indeed the major factor determining the transmembrane topology, with Arg and Lys being of nearly equal efficiency. His, although normally a very weak topological determinant, can be potentiated by a lowering of the cytoplasmic pH. Asp and Glu affect the topology to similar extents and only when present in very high numbers.

Amino Acid Sequence↗
PubMed1992

Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis-Dutch type share a decrease in cerebrospinal fluid levels of amyloid beta-protein precursor.

The amyloid beta-protein is a 39-42 amino acid peptide that is deposited in senile plaques and in cerebral vessel walls in individuals with Alzheimer's disease, Down's syndrome, hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), and, to a much lesser extent, normal aging. It is derived from abnormal proteolytic processing of its parent protein, the amyloid beta-protein precursor. Here we show that individuals with the HCHWA-D mutation and clinically manifesting the disease have markedly decreased cerebrospinal fluid levels of soluble amyloid beta-protein precursor (0.7 +/- 0.4 micrograms/ml) compared with age-matched normal subjects (3.0 +/- 0.2 micrograms/ml) as determined by quantitative immunoblotting and enzyme-linked immunosorbent assays. Similarly, age-matched patients diagnosed with probable Alzheimer's disease also have decreased cerebrospinal fluid levels of soluble amyloid beta-protein precursor (1.0 +/- 0.3 micrograms/ml). These parallel findings suggest a common biochemical marker for these two diseases and further establish the pathogenic relatedness of HCHWA-D and Alzheimer's disease.

Alzheimer Disease↗
PubMed1992

Patterns of serological markers in transfusion-transmitted hepatitis C virus infection using second-generation HCV assays.

A semiautomated dot blot assay and cDNA polymerase chain reaction (PCR) were used to study longitudinal anti-hepatitis C virus (HCV) recognition patterns in relation to presence of HCV-RNA in transfusion recipients and their infectious donors. In 9 recipients, 4 different patterns of HCV infection were observed: (A) persistent HCV carriage accompanied by chronic hepatitis in 6, (B) acute resolved hepatitis, but persistent HCV replication in one, and (C) continuous HCV replication without hepatitis in one and (D) acute resolved hepatitis with clearance of infection in one. This last self-limited infection was characterized by the disappearance of HCV-RNA as well as anti-HCV reactivity. In contrast, antibody reactivity persisted in 7 of 8 patients with chronic HCV infection who could be followed until 1990. Seven of the 9 recipients developed antibodies to all recombinant peptides in dot blot assay; one became positive for anti-C33 and anti-core and one developed anti-core only. The sequence of appearance of antibodies differed among individual patients. In 7 patients with full anti-HCV recognition patterns, the sequence of events was (mean and limits in days after transfusion): onset of hepatitis at day 50 (22-74), seroconversion of anti-C33 at day 91 (59-129), anti-core at day 133 (54-203), and anti-C100 at day 143 (59-365). The incorporation of C33 and core proteins, in addition to C100, in the second generation anti-HCV ELISA enhanced the detection rate in the HCV-infected transfusion recipients from 7/9 (78%) to 9/9 (100%).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗
PubMed1992

Parental origin and germline mosaicism of deletions and duplications of the dystrophin gene: a European study.

Knowledge about the parental origin of new mutations and the occurrence of germline mosaicism is important for estimating recurrence risks in Duchenne (DMD) and Becker muscular dystrophy (BMD). However, there are problems in resolving these issues partly because not all mutations can as yet be directly detected, and additionally because genetic ratios are very sensitive to ascertainment bias. In the present study, therefore, analysis was restricted to currently detectable mutations (deletions and duplications) in particular types of families which tend to be rare. In order to obtain sufficient data we pooled results from 25 European centers. In mothers of affected patients who were the first in their family with a dystrophin gene deletion or duplication, the ratio between the paternal and the maternal origin of this new mutation was 32:49 (binomial test P = 0.075) for DMD. In five BMD families the ratio between paternal and maternal origin of new mutations was 3:2. Recurrence risk because of maternal germline mosaicism was studied in sisters or subsequent sibs of isolated cases with an apparently new detectable mutation. In 12 out of 59 (0.20; 95% CI 0.10-0.31) transmissions of the risk haplotype the DMD mutation was transmitted as well. No recurrences were found in nine BMD families.

Chromosome Deletion↗
PubMed1992

Estimation of the male and female mutation rates in Duchenne muscular dystrophy (DMD).

We present the results of an international collaborative study aimed at estimating the ratio of male to female mutation rates in Duchenne muscular dystrophy based on the method of C. Müller and T. Grimm. With a sample size of 295, this ratio is found to be very close to 1, thus giving evidence for equal mutation rates in males and females in Duchenne muscular dystrophy.

Blotting, Southern↗
PubMed1992

The contribution of DNA analysis to carrier detection and prenatal diagnosis of hemophilia A and B.

Developments in DNA technology have provided a novel means of carrier detection and prenatal diagnosis of hemophilia A and B. The collection of a large set of data has enabled us to evaluate the present feasibility and reliability of a diagnosis at the gene level and its contribution to methods already available. Since 1984, 533 potential and obligate carriers belonging to 170 families with hemophilia have been referred to us. By the combined use of pedigree analysis, coagulation assays, and DNA (RFLP) analysis, certainty about the carrier status has been markedly increased for the potential carriers. Although RFLP analysis revealed the possible origin of the mutation in many families with an isolated patient, uncertainty remained for quite a number of their female relatives because of the possible occurrence of germline mosaicism. Forty-one women requested prenatal diagnosis during one or more pregnancies. The short time interval between pregnancies, even after abortion of an affected fetus, proved that first-trimester prenatal diagnosis has become an acceptable option for women at risk. Recently, efficient methods for direct identification of mutations have been developed, and they may allow a definite diagnosis for all families with hemophilia in the near future.

DNA↗
PubMed1992

Progressive dementia, without cerebral hemorrhage, in a patient with hereditary cerebral amyloid angiopathy.

A now 58-year-old female patient, carrier of the point-mutation in the beta-amyloid gene on chromosome 21 which causes hereditary cerebral hemorrhage with amyloidosis - Dutch type, developed progressive dementia after the age of 55 years. She never suffered from a cerebral hemorrhage. Dementia has been described as a feature of hereditary amyloid angiopathy before, but only in patients who also suffer from strokes. The clinical manifestation of the patient described here underlines the relation between the Dutch type of hereditary amyloid angiopathy and (familial) Alzheimer's disease.

Amyloid beta-Peptides↗
PubMed1992

Mapping around the Xq13.1 breakpoints of two X/A translocations in hypohidrotic ectodermal dysplasia (EDA) female patients.

Cellular hybrids were obtained from a t(X;12) identified in a female patient with hypohidrotic ectodermal dysplasia (EDA). This rearrangement had the same Xq13.1 cytogenetic breakpoint as a t(X;9) found in a previously observed EDA patient. A comparative analysis of these two rearrangements with nine probes was performed at the molecular level. These probes could define three subregions: three are proximal, two are distal, and four are between the two breakpoints. These last probes should prove useful for cloning the gene.

Blotting, Southern↗
PubMed1992

Carrier detection in X-linked ocular albinism of the Nettleship-Falls type by DNA analysis.

X-linked ocular albinism (XOA) is characterized by anomalies of the eyes and hypopigmentation or absence of pigment in skin, hair and eyes due to a hereditary inborn error of metabolism affecting the pigment cells. The gene of XOA of the Nettleship-Falls type (OA1) has been mapped to Xp22.3, and several closely linked RFLP loci have been identified. Linkage analysis and deletion mapping have established the marker gene order Xpter-STS-DX237-(OA1,DXS143,DXS85)-DXS1 6-DXS43-Xcen. Although the position of OA1 has yet not been fully resolved, we report on the first carrier detections in OXA of the Nettleship-Falls type by DNA analysis using markers which unquestionably flank OA1.

Albinism, Ocular↗
PubMed1992

Significant linkage disequilibrium between the Huntington disease gene and the loci D4S10 and D4S95 in the Dutch population.

Significant linkage disequilibrium has been found between the Huntington disease (HD) gene and DNA markers located around D4S95 and D4S98. The linkage-disequilibrium studies favor the proximal location of the HD gene, in contrast to the conflicting results of recombination analyses. We have analyzed 45 Dutch HD families with 19 DNA markers and have calculated the strength of linkage disequilibrium. Highly significant linkage disequilibrium has been detected with D4S95, consistent with the studies in other populations. In contrast with most other studies, however, the area of linkage disequilibrium extends from D4S10 proximally to D4S95, covering 1,100 kb. These results confirm that the HD gene most likely maps near D4S95.

Alleles↗
PubMed1992

Different mosaicism frequencies for proximal and distal Duchenne muscular dystrophy (DMD) mutations indicate difference in etiology and recurrence risk.

In about 65% of the cases of Duchenne muscular dystrophy (DMD) a partial gene deletion or duplication in the dystrophin gene can be detected. These mutations are clustered at two hot spots: 30% at the hot spot in the proximal part of the gene and about 70% at a more distal hot spot. Unexpectedly we observed a higher frequency of proximal gene rearrangements among proved "germ line" mosaic cases. Of the 24 mosaic cases we are aware of, 19 (79%) have a proximal mutation, while only 5 (21%) have a distal mutation. This finding indicates that the mutations at the two hot spots in the dystrophin gene differ in origin. Independent support for the different mosaicism frequency was found by comparing the mutation spectra observed in isolated cases of DMD and familial cases of DMD. In a large two-center study of 473 patients from Brazil and the Netherlands, we detected a significant difference in the deletion distribution of isolated (proximal:distal ratio 1:3) and familial cases (ratio 1:1). We conclude from these data that proximal deletions most likely occur early in embryonic development, causing them to have a higher chance of becoming familial, while distal deletions occur later and have a higher chance of causing only isolated cases. Finally, our findings have important consequences for the calculation of recurrence-risk estimates according to the site of the deletion: a "proximal" new mutant has an increased recurrence risk of approximately 30%, and a "distal" new mutant has a decreased recurrence risk of approximately 4%.

Blotting, Southern↗
PubMed1991

Presymptomatic, prenatal, and exclusion testing for Huntington disease using seven closely linked DNA markers.

Presymptomatic, testing, prenatal diagnosis, or exclusion testing are now available for persons at risk for Huntington disease. These tests will reduce uncertainty, assist in life planning, and prevent the birth of potentially affected children. We present the results of presymptomatic tests for 37 applicants including two prenatal and one exclusion test in 23 families. We initially used the markers G8, H5.52, F5.53, and pTV20 (D4S10), p8 (D4S62), and pRB1.6 (D4S81) and extended the informativity of the test at a later stage with the markers pKP1.65, C4H, S1.5 (D4S43), 674 (D4S95), 157.9 (D4S111), and YNZ32 (D4S125). Applicants with an unsuitable family structure were not admitted to the test. Of the 37 applicants, 33 were informative. In our hands the most efficient strategy is first to use the markers H5.52 (D4S10), pRB1.6 (D4S81), 674 (D4S95), pKP1.65 (D4S43), 157.9 (D4S111), YNZ32 (D4S125), and 252.3 (D4S115). The overall informativity in our data set was 84% and in the most recent test we achieved a 90-95% informativity. The other markers are used only when the first set is not informative.

DNA↗
PubMed1991

Multipoint linkage analysis in X-linked ocular albinism of the Nettleship-Falls type.

An extensive linkage analysis was performed by studying ten Xp22 loci in ten families segregating for X-linked ocular albinism of the Nettleship-Falls type (XOA). Linkage was confirmed between the XOA locus (OA1) and both DXS16 (theta max = 0.10, zeta max = 4.09) and DXS237 (theta max = 0.12, zeta max = 2.53). Linkage was found between OA1 and the loci DXS85 (theta max = 0.00, zeta max = zeta max = 4.37), DXS143 (theta max = 0.04, zeta max = 3.74), STS (theta max = 0.05, zeta max = 2.48), DXF30S1 (DXS278) (theta max = 0.07, zeta max = 8.79) and DXF30S2/3 (DXS278) (theta max = 0.00, zeta max = 14.93). An indication for linkage was found between OA1 and the loci DXS43 (theta max = 0.10, zeta max = 1.58) and DXS31 (theta max = 0.12, zeta max = 1.55). The analysis of multiple informative meioses suggests the order Xpter-(DXS31, DXS89)-(DXF30S1, DXS237)-(DXF30S2/3, OA1)-DXS143-(DXS16, DXS43)-Xcen. Various multipoint linkage analyses using the DNA loci order DXF30S1-STS-DXS237-DXS143-DXS16 significantly favour the position of OA1 between DXS237 and DXS143. These results further determine the genetic map around the XOA locus on the distal Xp and may be useful for DNA diagnosis in families with XOA.

Albinism, Ocular↗
PubMed1991

242 breakpoints in the 200-kb deletion-prone P20 region of the DMD gene are widely spread.

Using whole cosmids as probes, we have mapped 242 DMD/BMD deletion breakpoints located in the major deletion hot spot of the DMD gene. Of these, 113 breakpoints were mapped more precisely to individual restriction enzyme fragments in the distal 80 kb of the 170-kb intron 44. An additional 12 breakpoints are distributed over the entire region, with no significant local variation in frequency. Furthermore, deletion sizes vary and are not influenced by the positions of the breakpoints. This argues against a predominant role of one or a few specific sequences in causing frequent rearrangements. It suggests that structural characteristics or a more widespread recombinogenic sequence makes this region so susceptible to deletion. Our study revealed several RFLPs, one of which is a 300-bp insertion/deletion polymorphism. Abnormally migrating junction fragments are found in 81% of the precisely mapped deletions and are highly valuable in the diagnosis of carrier females.

Chromosome Deletion↗
PubMed1991

Prevalence of anti-HCV antibodies confirmed by recombinant immunoblot in different population subsets in The Netherlands.

The prevalence of antibodies to hepatitis C virus (anti-HCV) was studied in various population subsets in the Netherlands with anti-HCV C100 enzyme linked immunosorbent assay (ELISA), and confirmed with recombinant immunoblot assay (RIBA). Anti-HCV C100 ELISA positivity and RIBA positivity were found in 39 (0.7%) and 5 (0.1%) of 5,434 blood donors from Amsterdam; 25 (5%) and 2 (0.4%) of 481 blood donors from Surinam (South America); 19 (9%) and 2 (1%) of 213 multitransfused patients; 28 (4%) and 15 (2%) of 633 hemodialysis patients; 179 (80%) and 150 (67%) of 225 hemophilia A and B patients; 8 (80%) and 4 (40%) of 10 intravenous drug abusers; 18 (15%) and 2 (2%) of 119 anti-HIV-positive homosexual men; 2 (2%) and none of 106 anti-HIV-negative homosexual men; 6 (32%) and 3 (16%) of 19 patients with acute hepatitis non-A, non-B (NANBH); 13 (65%) and 8 (40%) of 20 patients with chronic NANBH and/or cryptogenic cirrhosis; and 4 (40%) and 1 (10%) of 10 patients with idiopathic autoimmune chronic hepatitis. Among blood donors, a positive correlation between a history of jaundice after the age of 18 years and the presence of RIBA-confirmed anti-HCV antibodies was found. Among both blood donors and hemodialysis patients, a positive correlation of RIBA-confirmed anti-HCV positivity with elevated alanine aminotransferase levels, but not with the presence of anti-hepatitis B core antibodies was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗