False negative cytogenetic result in direct preparations after CVS.
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Adult↗
Biomedical subjects
J Horst
Publications and source records attributed to J Horst.
Haemoglobin Freiburg: direct detection by synthetic oligonucleotide probes.
The molecular defect leading to Haemoglobin (Hb) Freiburg has been analysed using synthetic oligonucleotides. Oligonucleotide probes 19 residues and 16 residues long, corresponding to the normal and mutant beta-globin gene sequences, respectively, were used to develop a direct assay for the beta F-globin gene, which codes for an unstable haemoglobin. Under the conditions described here the use of the respective synthetic oligonucleotides should aid in the determination of all Hb Freiburg genotypes in families at risk with a high level of confidence.
DNA↗
Cystic fibrosis: typing 89 German families with linked DNA probes.
Three hundred and ninety-two subjects from 89 German families were typed for restriction fragment length polymorphisms (RFLPs) detected by the probes pmetH, pmetD, pJ3.11, KM19, and XV2c known to be tightly linked to the cystic fibrosis (CF) gene. The analysis of the predictive value of this typing in individual CF families indicates that the combined use of these probes provides a powerful diagnostic system for both carrier detection and prenatal diagnosis. In 45 families the complete haplotype including all RFLPs was available. Of them 41 (91.1%) were fully informative and 4 were partly informative.
Alleles↗
Phenylketonuria: distribution of DNA diagnostic patterns in German families.
The distribution of DNA haplotype constellations within the phenylalanine hydroxylase (PAH) gene was investigated in 44 German families affected with phenylketonuria (PKU). The haplotype frequencies differed significantly from those observed in a Danish population. Furthermore, ten haplotypes were identified in addition to the 12 previously described. In one of ten PKU alleles linked to haplotype 3, the G to A transition at the 5' splice donor site of intron 12 could not be confirmed with the use of synthetic DNA probes. According to these data, which are still limited, carrier testing and prenatal diagnosis should be possible in 70% of individuals at risk in the German population.
Alleles↗
Haemophilia A: carrier detection by DNA analysis.
From 46 families of predominantly German origin, afflicted with haemophilia A, 178 females were tested for carrier status. Two polymorphic restriction endonuclease sites, the extragenic marker locus DXS 52 (St 14 probe) and the intragenic Bcl I RFLP were investigated in these families. In some cases the results were corroborated by identifying (i) deletions within the factor VIII:C gene and (ii) eliminating a restriction endonuclease site. Two new alleles of the DXS 52 marker locus were found. According to this strategy, 27 women were classified as carriers and 74 as non-carriers. Forty-six women were classified as carriers according to pedigree analysis. Twenty-five females of families with sporadic cases and 6 test persons, who had mothers who where homozygous for the marker alleles, were diagnosed by additional use of conventional carrier detection.
Alleles↗
[The acardius amorphus].
We report on an acardius in a 47-year old tenthgravida. The postnatally detected acardius did not cause any obstetrical problems. The following theory seems to be the most suitable explanation for the development of an acardius: in a twin (multiple) pregnancy with blood vessel anastomoses between both twins, a twin with a haemodynamic advantage supplies the other one with oxygen-deprived blood; the latter thus becomes an acardius.
Abnormalities, Multiple↗
Hemoglobin M Iwate is caused by a C----T transition in codon 87 of the human alpha 1-globin gene.
DNA restriction, molecular cloning, and sequencing methods have been used to characterize the mutation leading to the methemoglobinemia HbM Iwate. It could be demonstrated that the HbM Iwate defect is caused by a point mutation involving a transition from C to T in the first position of codon 87 of the alpha 1-globin gene. Furthermore, the HbM Iwate mutation can directly be identified upon RsaI digestion. This direct detection of the mutation on the gene level is of significant advantage for differential diagnostic purposes.
Base Sequence↗
[Experiences with prenatal diagnosis of sickle cell anemia and thalassemias in the first trimester of pregnancy: various aspects for the obstetrician].
After an extensive educational campaign for the medical community in the area of the Westf. Wilhelms-University Münster five pregnancies at risk for sickle cell anemia and thalassemias were investigated during the first trimester of pregnancy. Following chorionic villi sampling in one case a sickle cell anemia and in two other cases a beta-thalassemia could be excluded. In two additional cases a homozygous beta-thalassemia was proven and in one of the cases the first trimester diagnosis was confirmed in the second trimester by fetal blood sampling. Because of the migration patterns in Europe there is currently a considerable demand for prenatal diagnosis of beta-thalassemias in West-Germany after proper information of the population at risk.
Anemia, Sickle Cell↗
DNA-diagnosis of sickle cell anemia from chorionic villi: possible influence of maternal cell contamination.
The admixture of maternal tissue is a possible hazard of prenatal diagnosis from chorionic villi. Therefore the tolerable degree of maternal DNA contamination in prenatal diagnosis of sickle cell anemia was investigated by mixing various amounts of DNA from HbS carriers with DNA from normal individuals and sickle cell anemia patients. The results indicate that lower rate of admixed maternal DNA does not prevent an exact direct DNA-diagnosis of sickle cell anemia.
Anemia, Sickle Cell↗
Hemoglobin Köln: direct analysis of the gene mutation by synthetic DNA probes.
The molecular defect leading to Hb Köln has been analyzed by synthetic oligonucleotides. Thus, DNA of 19 nucleotides, in length corresponding to the normal and mutant beta-globin gene sequences, were used to develop a direct assay for the beta k-gene that codes for this most common form of the unstable hemoglobins. The use of synthetic oligonucleotides established that the Hb Köln mutation is due to a G-to-A transition. The conditions described here should result in the determination of all Hb Köln genotypes with a high level of confidence.
Anemia, Hemolytic↗
Heterogeneity of the alpha-globin gene defects in German alpha-thalassemia affected families.
Analysis of alpha-thalassemia syndromes in several German families revealed DNA deletion as well as non-deletion forms as the molecular basis for the defects. Thus, the alpha-thalassemia haplotype was identified as the (-alpha)3.7 rightward deletion form, and the region of the putative recombination process generating such a deletion was further characterized. In addition three different alpha(0)-thalassemia haplotypes, (--)MED, (--) > 26, and (alpha alpha)T, could be detected using alpha- and zeta-globin gene-specific probes.
Chromosome Deletion↗
DNA-polymorphic patterns linked to the beta-globin genes in German families affected with hemoglobinopathies and thalassemias: a comparison to other ethnic groups.
DNA haplotype constellations of the beta-globin gene cluster have been analyzed in German families with hemoglobinopathies (Hb Freiburg, Hb Köln, Hb Presbyterian) and beta-thalassemias. The polymorphic patterns obtained were compared to those found in families from Greece, Italy, and Turkey affected by beta-thalassemia syndromes. With the combined analysis of seven restriction site polymorphisms a DNA-diagnostic prediction for additional offspring could be made with an overall frequency of 75% in the four ethnic groups.
DNA↗
Detection of a restriction site polymorphism within the human alpha-globin gene complex.
A mutant Rsa I restriction endonuclease site of high frequency has been identified in individuals of German, Greek, Italian, and Turkish origin. The mutation was found within the alpha-globin gene complex and is located 0.7 kb 5' to the alpha 2-globin gene. In individuals of central European origin 34 out of 58 chromosomes exhibited the alpha-gene linkage to the presence of the polymorphic site, and thus a preliminary estimate of the gene frequency for this allele would be 0.59. DNA analysis data of individuals derived from Mediterranean populations indicate a distribution of this polymorphic marker in similar frequencies.
Alleles↗
Hemoglobin Köln: analysis of linkage relationships between the mutant gene and polymorphic restriction sites in the beta-globin gene cluster.
Nuclear DNA has been analyzed by means of restriction endonuclease mapping procedure to identify chromosomes that carry mutant Hb Köln beta-globin genes in a family with individuals heterozygous for this disease. Inherited DNA polymorphisms within the beta-globin gene cluster yielded a direct linkage of the Hb Köln mutation to haplotype constellations that are diagnostic for further offspring.
Carrier Proteins↗
Alpha-globin gene deletion causes alpha-thalassemia syndromes in two German families.
Restriction endonuclease mapping of chromosomal DNA has been used to determine whether the alpha-globin gene deletion or non-deletion form of alpha-thalassemia is the underlying molecular defect in individuals of two unrelated German families with alpha-thalassemia syndromes. The obtained DNA pattern in all cases indicated loss of alpha-globin genes resulting in -alpha/alpha alpha, --/alpha alpha, and --/-alpha genotypes in alpha-thalassemia-2, alpha-thalassemia-1, and Hb H individuals respectively. The chromosomes showing loss of one alpha-globin gene in alpha-thalassemia-2 and Hb H disease were characterized by the so-called rightward deletion form exhibiting loss of a 3.7 kb DNA fragment in the alpha-gene cluster.
Chromosome Deletion↗
DNA restriction mapping identifies the chromosome carrying the mutant Hb Presbyterian beta-globin gene.
Restriction endonuclease mapping of cellular DNA has been used to identify chromosomes that carry the mutant Hb Presbyterian beta-globin genes in a family with individuals heterozygous for this disease. The presence of the polymorphic Hind III restriction site in the G gamma-globin gene and its absence in the A gamma-globin gene were shown to be in phase with the Hb Presbyterian mutation yielding a haplotype constellation that is diagnostic for any further affected offspring.
Chromosome Mapping↗
Hb M Milwaukee: direct detection of the beta-globin gene mutation in three generations of an afflicted family.
Chromosomal DNA from three individuals with familial hemoglobin M (Hb M) Milwaukee was studied by restriction endonuclease analysis. The segregation of the mutant beta-globin gene could be followed through three generations by direct Sst I analysis at the gene level. Various restriction endonucleases were used to confirm the positions of Sst I sites in the delta-beta A- and delta-beta Mi-globin gene regions.
Base Sequence↗
Analysis of the Hb M Milwaukee mutation at the DNA level.
Restriction endonuclease mapping of cellular DNA with the enzyme Sst I has been used to detect the haemoglobin (Hb) Milwaukee mutation directly. Instead of a normal 15.5 kilobase pairs (kb) fragment which contains the normal beta-globin structural genes, in heterozygous Hb M Milwaukee DNA two additional fragments of 9.0 kb and 6.5 kb were obtained that are diagnostic for this anomaly. The position of Sst I sites within the beta-globin gene region could be established.
Base Sequence↗