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Biomedical subjects

E Schwinger

Publications and source records attributed to E Schwinger.

At least 127 records · Page 7Linked to original sources
PubMed1991

Pro-347-Arg mutation of the rhodopsin gene in autosomal dominant retinitis pigmentosa.

It has been shown recently that autosomal dominant retinitis pigmentosa may be caused by point mutations of the rhodopsin gene in a portion of families. In this communication, a large six-generation family with autosomal dominant RP is described. Molecular analysis by PCR amplification followed by restriction digestion or heteroduplex analysis suggested a point mutation in codon 347, in which two different mutations (Pro-347-Ser and Pro-347-Leu) have already been reported. Direct sequencing of the patients' DNA revealed a previously undescribed CCG----CGG transversion in codon 347 predicting a Pro----Arg substitution. Ophthalmological data of the patients are summarized and compared to those of patients with other mutations in the rhodopsin gene.

Base Sequence↗
PubMed1991

Analysis of a dystrophin gene deletion by amplification of mRNA isolated from DMD myotubes cultured in vitro.

The most frequent causes for the X-linked muscular dystrophy of the allelic Duchenne (DMD) or Becker (BMD) type are partial deletions of the dystrophin gene. These mutations are accompanied either by disrupted or by preserved translational reading frames in mRNAs derived from the deleted genes. As a rule, the reading frame is destroyed in the more severe DMD, whereas it is preserved in the less severe BMD (M. Koenig et al., 1989, Am. J. Hum. Genet. 45, 498-506). We have analyzed in detail a deletion that was detected in a fetus at risk of DMD. The analysis of this mutation included the delineation of the altered subregion in the dystrophin mRNA. mRNA was isolated from myotubes derived from embryonic DMD myoblasts propagated in vitro. This study was based on enzymatic amplification by the polymerase chain reaction (PCR) of dystrophin mRNA and direct sequencing of the amplified cDNA. Exons 47 to 50 were found to be missing in the mRNA. The splicing of exon 46 to exon 51 resulted in a reading frameshift, indicating that this mutation is likely to be responsible for a DMD type of dystrophy. The clinical diagnosis of DMD for a 10-year-old patient in this family was compatible with the "reading frame" assumption.

Base Sequence↗
PubMed1991

[Diagnosis of fetal virus infections by in situ hybridization].

Non-radioactive in situ hybridization of formalin-fixed paraffin-embedded placental and foetal tissue, using virus-specific DNA or RNA probes, may be helpful for the diagnosis of foetal virus infection causing foetal hydrops, granulomatous placentitis and abortion. We present four cases of intrauterine CMV-, Parvo-B19- and Varicella-Zoster virus infection, in which this diagnostic method established detection of the virus.

Adult↗
PubMed1991

A simplified protocol for fluorescence in situ hybridization with repetitive DNA probes and its use in clinical cytogenetics.

A method for chromosome-specific staining and its use in clinical cytogenetics is described. This fluorescence in situ hybridization protocol for repetitive DNA probes results in yellow-green fluorescent signals on orange-red stained chromosomes. Special characteristics are its simplicity, the use of digoxigenin-11-dUTP for labeling, and the combination of high stringency criteria for hybridization and low stringency for washing. The method is particularly advantageous in cases with structurally abnormal extra chromosomes (ESACs), marker chromosomes of gonosomal origin, and chromosomal mosaicism. It may also facilitate the screening of cases for fragile X. The chromosome-specific staining can be done within 1 working-day.

Chromosome Aberrations↗
PubMed1991

[Autosomal dominant hereditary retinopathia pigmentosa with genetic heterogeneity].

There is considerable clinical variability in autosomal dominant retinitis pigmentosa (ADRP). The underlying biochemical defect had remained unknown until recently, so that it was not possible to determine the primary cause(s) of this phenotypic diversity. Recently, different point mutations and base pair deletions have been identified in the rhodopsin gene in a proportion of patients with ADRP, providing convincing evidence for allelic genetic heterogeneity in this disease. We screened a total of 65 patients with ADRP in Germany, Austria, and Switzerland for the presence of the point mutations described recently at codons 58 and 347 in patients in the USA. Our results show that the frequency of point mutations at codon 347 in the patients studied here is about 3%, a figure similar to that found in the USA. The frequency of the mutation at codon 58 seems to be generally low. The identification of patients with point mutations in the rhodopsin gene offers the possibility, for the first time, of studying the correlation between genotype and disease phenotype.

Chromosome Aberrations↗
PubMed1990

Clinical diagnosis of partial duplication 7q.

We report on two sibs with partial dup (7q), a retarded 9-month-old boy and an aborted fetus of 17 weeks' gestational age. Besides minor anomalies, the boy had frontal bossing, macrocephaly with hydrocephaly, a high forehead, and a large fontanelle. GTG banded chromosomes showed a 14p+ abnormality. Because his mother carries a balanced, de novo translocation with a breakpoint in band 7q33, the boy has a duplication of the distal portion of band 7q33 and the segment 7q34----qter. Our findings suggest that the phenotype in terminal duplications of 7q may, in some patients, be recognized clinically.

Abnormalities, Multiple↗
PubMed1989

Chromosome mosaicism of the placenta--a cause of developmental failure of the fetus?

Fourteen (2.5 per cent) of 568 chromosome preparations after CVS showed discrepancies between the placental and fetal karyotype, mainly due to placental mosaicism. The presence of a second cell line within the placenta was confirmed in all but one case, in which cytogenetic reinvestigations were carried out. Our clinical data indicate that severe developmental retardation in the newborn is not to be expected if only the placenta carries the chromosomally abnormal cell line.

Chorionic Villi↗
PubMed1989

Is there a correlation between morphological and cytogenetic findings in placental tissue from early missed abortions?

A retrospective study of 200 missed abortions was performed to determine whether morphological criteria alone are sufficient to ascertain a chromosomal aetiology. Placental changes were classified into five morphological and four morphometric groups, according to the severity of alterations, and were then correlated with the cytogenetic data. The rate of chromosome anomalies was approximately 50% and was thus not significantly different within the groups II-V, but it was 80% in group I, which covered the most severe placental alterations, namely the partial hydatidiform moles. There was a high incidence of triploidies in group I, trisomies with obligatory early lethality in groups II and III, and X-monosomies in group III. Our findings do not support previous evidence regarding the specificity of certain villous alterations in association with chromosome aberrations. Indeed, they indicate that the placental villi may react similarly to chromosomal and non-chromosomal disturbances and that placental morphology depends on the severity and the temporal onset of the underlying disorder rather than on its type. With respect to chorionic villus samplings (CVS), this would mean that an abnormal villous structure may be suggestive for a chromosome anomaly but does not exclude a normal karyotype.

Abortion, Missed↗
PubMed1989

X-chromosomal DNA polymorphisms in two ethnic groups from India.

Four polymorphic sites of the short arm of the X chromosome were studied in two racial groups from India, the Assamese and the Malayalee. Since the allelic frequencies of the two groups did not differ markedly from each other, the data from the two populations were pooled. The frequency of the A2 allele was 0.57 for the L1.28 probe, 0.20 for the RC8 probe, 0.28 for the pD2 probe and 0.11 for the L754 probe. The A3 allelic fragment of the RC8 probe was not found among 67 Indians, and in one Assamese woman an additional 7.0-kilobase fragment was found. The differences between the Indian population and other ethnic groups were analyzed.

Alleles↗
PubMed1988

The effect of restriction enzyme digestion of human metaphase chromosomes on C-band variants of chromosomes 1 and 9.

Human metaphase chromosomes, fixed on slides, have beent treated with 8 different restriction endonucleases and 29 combinations of 2 restriction enzymes prior to staining with Giemsa. The endonucleases AluI and DdeI and the combinations AluI + DdeI, AluI + HaeIII, AluI + HinfI, and AluI + MboI have then been used to digest metaphase chromosomes of nine individuals with C-band variants of chromosomes 1 or 9, obtained by the CBG technique. The restriction enzyme resistant chromatin of the paracentromeric regions of chromosomes 1 and 9 has been measured and compared with the corresponding CBG-bands. The size of the enzyme resistant chromatin regions depend upon the type of enzyme(s) used. Treatment with AluI + MboI was the only digestion that acted differently on different chromosome pairs. However, within one pair of homologous chromosomes, all digestions revealed the same variations as conventional C-banding.

Chromosome Banding↗
PubMed1988

[Double heterozygosity (transferase-/epimerase-defect) and galactosemia cataract].

The mother of a boy who suffered from classical galactosaemia (galactose-1-phosphate uridyl transferase deficiency) has unilateral cataracta. In addition the boy had a decreased activity of the UDP-galactose-4-epimerase. The latter defect could also be demonstrated in the erythrocytes from the mother and the grandmother. In contrast to the finding of cataracta in the mother the grandmother with the same type of double heterozygosity was ophthalmologically normal. The implication of partial maternal disorders of galactose metabolism will be discussed in view of their possible role for the origin of cataracta.

Carbohydrate Epimerases↗
PubMed1988

[Puncture of the chorionic villi. Technic--experiences--risks].

Chorion villi biopsy is a recently introduced method for first trimester prenatal diagnosis. Based on 435 cases of chorionic villi biopsies, obtained during a 3 year period, we report our experiences with the technique of chorionic villi sampling, chromosomal analysis from trophoblast tissue and possibly associated complications, such as spontaneous abortions, vaginal bleeding, and chromosomal mosaicism. The rate of spontaneous abortions in our group of patients was 3%. This appears low, considering the high overall spontaneous abortion rate in early pregnancy of women over 35 years. The cytogenetic diagnosis is complicated by a high rate (2.8%) of chromosomal mosaicism, which were found to be not representative for the fetus, but required control amniocentesis. From our experiences with this method we conclude that chorion villi biopsy can be offered as a reliable alternative method to amniocentesis in the hands of an experienced team of obstetric surgeons and cytogenetists.

Abortion, Spontaneous↗
PubMed1987

Spermatogenesis in two patients with the fragile X syndrome. I. Histology: light and electron microscopy.

Light and electron microscopic studies on testicular biopsies were carried out in two men, 40 and 44 year old, with the fra(X) form of mental retardation and macroorchidism. Distinct interstitial edema, an increased amount of lysosomal inclusions in Sertoli cells, and disturbance of spermatid differentiation were found in both probands. Additionally, some extent of tubular atrophy was demonstrated in one patient. The impairment of spermatogenesis is discussed with respect to pressure effects on the germinal epithelium due to the edema.

Adult↗
PubMed1987

Roberts syndrome and SC phocomelia. A single genetic entity.

A family with three siblings showing different manifestations of Roberts syndrome or SC phocomelia is described. With regard to previously published cases of familial Roberts syndrome and SC phocomelia we conclude that these two syndromes are one and the same genetic entity.

Abnormalities, Multiple↗
PubMed1987

Two different XY-quadrivalent associations and impairment of fertility in men.

One sterile and one subfertile man with balanced reciprocal autosomal translocations, a t(9;15), and a t(14;21), were analyzed using whole mount pachytene spreads, histology, and semen analyses. In both probands with different types of quadrivalent complexes lack of pairing near the translocation breakpoints and significant associations with XY bivalents were found. Variability in the frequency of XY-quadrivalent contacts and an increase in late pachytene to 52% in t(9;15) and 90% in t(14;21) could be observed. The lower rate was associated with reduced postmeiotic spermatogenesis and the higher rate with complete spermatogenic arrest. In both translocation carriers the XY-quadrivalent association is considered to be the main cause for testicular malfunction rather than nonpaired segments in the multivalent complexes.

Chromosome Banding↗
PubMed1987

Four DNA polymorphisms on the short arm of the X chromosome: allele frequencies in a German and in a Turkish population.

Four restriction fragment length polymorphisms, revealed by cloned arbitrary X chromosome segments (L1.28, RC8, pD2, 754) were studied in samples (50 individuals each) of a German and a Turkish population. All previously reported alleles of these polymorphisms were found in both populations, except the infrequent RC8 allele B3 (3.0 kb fragment), which was absent in both groups. The observed minor alleles were found to be rarer in the German series than in the Turkish group, but there was no conclusive evidence of essentially different allele frequencies in either population. However, the frequencies of the RC8 allele B2 (5.3 kb fragment) were differing at the 5% significance level. The allele frequencies of the four polymorphisms are presented and compared with those reported from other European regions.

Gene Frequency↗