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Biomedical subjects

H Scheffer

Publications and source records attributed to H Scheffer.

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

Confirmation of clinical diagnosis in requests for prenatal prediction of SMA type I.

The recent discovery of a major SMA-locus in the chromosomal region 5q makes it possible to carry out prenatal DNA studies in families in which a child with SMA type I has been born. Since direct mutation analysis is not yet possible, the reliability of prenatal prediction of SMA type I usually depends on the certainty of the clinical diagnosis in the index patient. Sixteen requests were received for DNA studies in couples who had had a previous child with SMA type I. After re-evaluation, the performance of prenatal diagnosis was rejected in four cases. Among the other twelve families prenatal DNA analysis of chorion villus biopsies has been carried out in three families. In all three cases the fetus had inherited the high-risk haplotypes from both parents, and the parents chose to terminate the pregnancy. An illustration of the prenatal DNA studies in one family is given. The importance of confirmation of the diagnosis SMA type I before performing DNA studies is emphasised.

Biopsy↗
PubMed1992

Analysis of a metastasizing testicular mixed gonadal stromal tumor with osteosarcoma components suggests that a malignant tumor with the histology of osteosarcoma may develop without primary involvement of RB1 and TP53.

A malignant stromal tumor of the testis with an osteosarcoma component and five of its metastases mainly containing osteosarcoma have been analyzed for RB1 and TP53 abnormalities. Whereas in the primary tumor and in some of the metastases loss of heterozygosity could not be detected for RB1 or for the 17p13 region in which TP53 is located, other metastases showed such losses of heterozygosity. By polymerase chain reaction analysis an 18-base pair deletion from exon 5 of the TP53 gene was found in a small proportion of primary tumor cells and in one of the metastases, but not in the other metastases. Therefore, in this case neither RB1 nor TP53 seems to play an essential role in the initiation of osteosarcoma.

Amino Acid Sequence↗
PubMed1992

Chromosomal sublocalization of the 2;13 translocation breakpoint in alveolar rhabdomyosarcoma.

A characteristic balanced reciprocal chromosomal translocation [t(2;13)(q35;q14)] has been identified in more than 50% of alveolar rhabdomyosarcomas. As the first step in characterization of the genes involved in this translocation, we constructed somatic cell hybrids that retained either the derivative chromosome 2 or the derivative chromosome 13 without a normal chromosome 13 homologue. Ten linked DNA probes known to be located within bands 13q13-q14 were mapped relative to the breakpoint on chromosome 13, allowing localization of the breakpoint region between two loci separated by 5.5 cM. A long-range restriction map extending approximately 2,300 kb around these loci failed to provide evidence of rearrangement. Additionally, we confirmed that the FMS-like tyrosine kinase gene (FLT), previously localized to 13q12 by in situ hybridization, is located proximal to the breakpoint, and we demonstrated that FLT is not a target for disruption by this tumor-specific translocation.

Blotting, Southern↗
PubMed1992

Prenatal diagnosis in a family with X-linked chronic granulomatous disease with the use of the polymerase chain reaction.

In the X-linked form of chronic granulomatous disease (X91 degrees CGD), the genetic defect is linked to the CYBB locus on the X chromosome. We studied a family with a genetic defect in this gene, consisting of a G----A substitution at the fifth base of the 5' donor splice site of intron 3. This mutation leads to skipping of exon 3 after transcription of the gene. The expectant mother was diagnosed as a carrier. Analysis of polymerase chain reaction (PCR)-amplified genomic DNA from a chorionic villus biopsy (CVB) showed the same mutation in the male fetus. After termination of the pregnancy, the diagnosis was confirmed by conventional methods. This is the first time that PCR has been used for prenatal diagnosis of CGD.

Abortion, Eugenic↗
PubMed1992

Identification of crossovers in Wilson disease families as reference points for a genetic localization of the gene.

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. A minimum recombinant analysis using D13S22, ESD, RB1, D13S31, D13S55, D13S26, D13S39, and D13S12, all localized at 13q14-q22, has been carried out in 20 WD families of Northwest-European origin. No inconsistencies have been observed with respect to locus order or location of the WD locus (WND) compared with previous linkage studies. D13S31 was mapped as the closest marker proximal to WND, whereas D13S55 and D13S26 were mapped as the closest markers distal to WND. We have identified a crossover between WND and D13S31 in one family and a crossover between WND and D13S55 in another. These crossover sites can be used as reference points for new chromosome 13q14-q21 markers, and are therefore important for a more accurate mapping of the WD locus.

Chromosome Mapping↗
PubMed1992

[Carrier detection in cystic fibrosis. Various illustrative examples].

Until 1989 carrier detection in families with cystic fibrosis (CF) took place by means of linkage analysis with polymorphic DNA markers. This is an indirect method to demonstrate carriership. For linkage analysis it is often essential that there is patient material available. Since the identification of the CF gene, direct DNA analysis of the most frequent CF mutations is possible. This allows direct demonstration of carriership by means of DNA analysis in the majority of cases, without the necessity always to investigate family members. Carriership detection of persons not related to CF patients, for example partners of CF carriers, is with this method also possible. In cases where none of the frequent CF mutations can be found, linkage analysis may still prove helpful. In this article we demonstrate some clinical examples of carrier investigation.

Child, Preschool↗
PubMed1991

Consanguinity sans reproche.

In a family with two cystic fibrosis (CF) patients and consanguineous parents, DNA analysis showed that the CF in the children was not caused by homozygosity by descent, since two different mutations were involved. A formula is given for calculating the probability that parental consanguinity, if it exists, is causally related to the existence of an autosomal recessive disease in affected children.

Alleles↗
PubMed1991

Partial 3q duplication syndrome and assignment of D3S5 to 3q25-3q28.

We report a girl with a de novo duplication of the distal part of the long arm of chromosome 3 and review the literature. Our patient had the facial characteristics and many other anomalies of the partial 3q duplication syndrome. As a hitherto undescribed symptom in partial 3q trisomy syndrome, she had microphthalmia. The karyotype of this girl was interpreted as an inverse duplication of the terminal portion of chromosome 3: 46,XX,inv dup (3)(pter-q28::q28-q25::q28-qter). Quantitative hybridisation studies with 3p and 3q probes gave a consistent 3:2 ratio of the relative intensities of the q bands in relation to the p bands between patient and control. This confirmed the presence of a 3q duplication and delineated the location of D3S5 to 3q25-3q28.

Blotting, Southern↗
PubMed1991

Complete association of loss of heterozygosity of chromosomes 13 and 17 in osteosarcoma.

Mutations of the retinoblastoma (RB1) gene are not confined to retinoblastoma, but are also involved in the development of osteosarcoma. Structural aberrations within the RB1 gene have been studied in fresh samples of eleven cases of osteosarcoma. In five cases a rearrangement was detected, one of which was best explained as a partial duplication. The chromosomal mechanisms by which the nonmutated RB1 allele was lost appeared to be similar in frequency to those that have been reported for retinoblastoma. Loss of heterozygosity was observed for chromosomes 3, 11, 13, 17, and 22. However, when no loss of heterozygosity of chromosome 13 was detected, the other chromosomes retained their heterozygosity as well. A complete association of loss of heterozygosity of chromosomes 13 and 17 was observed. This can be taken as an indication of the involvement of another tumor suppressor gene at chromosome 17 in the initiation of osteosarcoma.

Adolescent↗
PubMed1990

[Carrier detection in relatives of patients with cystic fibrosis and their partners].

In the clinical genetics centres of Groningen and Rotterdam carrier detection by means of DNA analysis was performed in 55 relatives of cystic fibrosis patients at their request; 32 of them were siblings, 22 were uncles and aunts, and one was a first cousin. In 31 of them carriership could be demonstrated. Carrier detection was also performed in 23 of their partners, in 3 partners of female CF patients, and in 4 AI donors. In one of the partners of the carriers carriership was demonstrated also. This is the first couple in The Netherlands to whom information on the 25% risk of CF in a future child and on the corresponding reproductive options could be given prior to the birth of a first affected child. Since not all mutations of the CF gene are detectable with present methods, carrier detection still has its restrictions, which are discussed.

Adult↗
PubMed1990

Close linkage of the Wilson's disease locus to D13S12 in the chromosomal region 13q21 and not to ESD in 13q14.

Wilson's disease (WD) is an autosomal recessive disorder resulting in copper accumulation notably in liver and brain tissue. Linkage of the WD locus (WND) to ESD at 13q14 was first shown by studies in families of Middle Eastern origin using the isozymic polymorphism of esterase D. Using RFLPs detected by the ESD cDNA we could not confirm this reported close linkage in an analysis of 17 WD families of northwest European origin. A tight linkage was detected, however, to the marker D13S12, located more distally at 13q21. No obligate cross-overs were detected in 63 gametes informative for this marker. Our data confirm an assignment of WND to 13q14-21. Its localization, however, seems to be more distal to ESD than previously reported. Although genetic heterogeneity cannot be excluded, the observed differences between the two populations are probably due to random variation.

Carboxylesterase↗
PubMed1990

Frequency of the delta F508 mutation and XV2c,KM19 haplotypes in cystic fibrosis families from The Netherlands: haplotypes without delta F508 still in disequilibrium.

We have determined the frequency of the major cystic fibrosis (CF) three base pair deletion (delta F508) mutation in 152 CF chromosomes from patients originating from the northern part of The Netherlands. In these patients, the deletion represents approximately 76% of CF mutations. Meconium ileus is strongly associated with homozygosity for the delta F508 mutation. The XV2c,KM19 haplotypes on the CF chromosomes without the delta F508 mutation are in disequilibrium with the population frequency, although showing an increased frequency of the 1 2 haplotype. The surplus of this haplotype is almost entirely made up by the pancreatic insufficient patients.

Cystic Fibrosis↗
PubMed1989

Linkage analysis of families with hereditary retinoblastoma: nonpenetrance of mutation, revealed by combined use of markers within and flanking the RB1 gene.

Nonpenetrance of the inherited mutation responsible for retinoblastoma has been reported. By DNA analysis in families with hereditary retinoblastoma, it is possible to identify healthy individuals in whom the mutation is nonpenetrant. This requires the use of DNA markers both within and flanking the retinoblastoma gene. We have analyzed the segregation of several markers in 19 families (69 meioses) with hereditary retinoblastoma. In two families a carrier was identified who showed nonpenetrance of the mutation predisposing to retinoblastoma. The intragenic markers were informative in 15 pedigrees. The use of flanking markers from the same chromosomal region caused an increase of the number of informative families to 18. No crossing-over within the gene was observed. In one family an inherited deletion involving one of the RB1 alleles was detected. Our findings emphasize the use of a combination of both intragenic and flanking markers to obtain both the highest reliability of carrier detection in families with hereditary retinoblastoma and an accurate estimate of the frequency of nonpenetrance.

Chromosome Deletion↗
PubMed1988

A human glioblastoma line with karyotypic nullisomy 13 containing several chromosome 13-specific sequences.

Using a biochemical approach (evaluation of esterase D activity) and recombinant DNA techniques (in situ and filter hybridization with specific DNA probes) a glioblastoma cell line with karyotypical nullisomy 13 was shown to contain several chromosome #13-specific sequences. They were assigned to a marker chromosome. This finding suggests that cytogenetic descriptions of deletions or chromosome losses will gain considerable power of the statement when supplemented by molecular analysis, particularly since, by now, DNA probes have been accumulated for all chromosomes and all their subfragments.

Chromosome Banding↗
PubMed1988

Eight closely linked loci place the Wilson disease locus within 13q14-q21.

Wilson disease (WD) is an autosomal recessive disorder resulting in an accumulation of copper in the liver, brain, and other organs. The WD locus (WND) has previously been linked to esterase D (ESD) and localized to 13q14-22. With the large Centre d'Etude Polymorphisme Humain cohort, a refined map of DNA markers from this region was constructed, with the following locus order: D13S1-D13S21-D13S22-D13S10-ESD-RB-WND-D 13S26-D13S12-D13S2. A significant excess of male recombination was observed between D13S21 and D13S22. Intervals distal to D13S22 showed an excess of female recombination. When these markers were tested on 19 WD families from a variety of ethnic backgrounds, the two closest loci were shown to be RB and D13S26. The retinoblastoma gene locus (RB) was shown to be proximal to WND at a distance of 4.4 centimorgans (cM), and D13S26 was placed distal to WND at a distance of 4.0 cM. ESD was assigned proximally at a distance of 9.4 cM. In all families studied WND was linked to one or more of the loci ESD, RB, or D13S26.

Chromosome Mapping↗