Search PubMed⌕ Search

Biomedical subjects

E Passarge

Publications and source records attributed to E Passarge.

At least 37 records · Page 2Linked to original sources
PubMed1995

Molecular analysis and predictive testing in retinoblastoma.

Predictive testing using molecular analysis is an integral part of contemporary retinoblastoma management. We have made extensive use of segregation analysis for risk assessment in both familial and sporadic disease. Investigation of loss of heterozygosity in tumor samples proved to be invaluable for the identification of linkage phase. In many families, however, accurate carrier risk assessment depends on direct identification of the causative R B I mutation. Consequently, we have developed methods for rapid mutation screening. Using these techniques, mutation analysis can now be offered to an increasing number of individuals.

DNA Mutational Analysis↗
PubMed1995

A nine-month-old boy with microcephaly, cataracts, intracerebral calcifications and dysmorphic signs: an additional observation of an autosomal recessive congenital infection-like syndrome?

A nine-month-old boy with microcephaly, cataracts, intracerebral calcifications and dysmorphic signs: an additional observation of an autosomal recessive congenital infection-like syndrome?: We present a nine-month-old boy with microcephaly, cataracts, intracerebral calcification, dysmorphic facial signs, and a clinical course resembling a congenital intrauterine infection. The serological screening for connatal infections repeatedly was negative. Patients with congenital infection-like syndrome previously described showed similar clinical features. The recurrence of the disease in sibships suggests autosomal recessive inheritance. We add a possibly new patient with this condition, review the literature, and demonstrate the difficulties in making the diagnosis of an infection-like syndrome in a single patient.

Abnormalities, Multiple↗
PubMed1994

Distinct RB1 gene mutations with low penetrance in hereditary retinoblastoma.

The interfamilial diversity in penetrance and expressivity of hereditary retinoblastoma was investigated in 29 families. By using a simple parameter for estimating the severity of the disease (diseased-eye-ratio), we were able to identify four families with a discrete low-penetrance phenotype. The underlying genetic defect was identified in three families. One family has a 3-bp deletion in exon 16 that results in the deletion of Asn480. In two further unrelated families, the identical missense mutation at codon 661 in exon 20 (CGG to TGG, Arg to Trp) was identified. These mutations are distinct from the majority of retinoblastoma gene alterations, as they do not result in the disruption of the gene product. We propose that reduced penetrance of retinoblastoma is the result of a residual function of these alleles in retinoblastoma precursor cells.

Base Sequence↗
PubMed1994

Frequency and parental origin of hypermethylated RB1 alleles in retinoblastoma.

The retinoblastoma susceptibility (RB1) gene contains an unmethylated CpG-rich island at its 5' end. Using methylation-sensitive restriction enzymes, we have investigated the methylation status of this island in 21 sporadic unilateral retinoblastomas and 30 hereditary retinoblastomas. Three sporadic unilateral tumors were found to have hypermethylated RB1 alleles. In two tumors, the paternal allele was methylated, whereas the maternal allele had been lost. Cultured cells from one of these tumors were studied by the reverse transcription polymerase chain reaction and found to have a reduced level of RB1 mRNA. The third tumor had retained constitutional heterozygosity, and the paternal allele was specifically methylated. The combined data from previously published reports and from this study show that hypermethylation of the RB1 gene occurs in 13% of sporadic unilateral tumors and may reduce gene activity.

Base Sequence↗
PubMed1994

Spectrum of small length germline mutations in the RB1 gene.

A screening method based on multiplexed automated fragment length analysis of polymerase chain reaction products was used to identify germline mutations in the RB1 gene. By screening 106 unrelated patients with hereditary retinoblastoma, 20 small deletions (1-18 bp) and seven insertions (1-5 bp) were identified. When collating our data with reported mutations, recurrence of small length mutations was observed at nine sites within the RB1 gene. Most of these contained monotonic runs or direct repeats embedded in homocopolymer tracts. While the majority of mutations resulted in premature truncation, two mutations caused an in-frame loss of F755 and G540 to E545, respectively. A genotype-phenotype comparison of patients carrying different small length mutations did not reveal any consistent relation. Particularly, the two patients with in-frame mutations showed a high number of tumours consistent with regular-penetrance retinoblastoma.

Base Sequence↗
PubMed1993

New autosomal recessive lethal disorder with polycystic kidneys type Potter I, characteristic face, microcephaly, brachymelia, and congenital heart defects.

We report on 3 pairs of sibs from unrelated families, who present with polycystic kidneys Potter type I claimed to be specific for the ARPKD, and with microbrachycephaly, hypertelorism with telecanthus, large posteriorly angulated fleshy ears and various congenital malformations including congenital heart defects. We suggest that they represent a previously unrecognized autosomal recessive lethal developmental disorder within the group of infantile polycystic kidney disease and Potter sequence.

Abnormalities, Multiple↗
PubMed1991

Syndrome of developmental retardation, facial and skeletal anomalies, and hyperphosphatasia in two sisters: nosology and genetics of the Coffin-Siris syndrome.

We report on 2 sisters, 3 and 6 years old, with a possible new syndrome consisting of developmental retardation, facial and skeletal anomalies, and hyperphosphatasia. This disorder closely resembles the Coffin-Siris syndrome (McKusick number 135900). We describe the difficulties in achieving a diagnosis. A major diagnostic clue was the radiological recognition of hypoplasia/aplasia of the terminal phalanx of the 5th finger. Minor facial anomalies and mental retardation alone had not led to the proper diagnosis. Still, several diagnostic possibilities remain. For unknown reasons both children have an increased level of serum alkaline phosphatase activity.

Abnormalities, Multiple↗
PubMed1991

Characterization of deletions at the retinoblastoma locus in patients with bilateral retinoblastoma.

DNA samples from 92 unrelated patients with bilateral retinoblastoma were analyzed by Southern blot hybridization with cDNA and genomic clones of the retinoblastoma (RB-1) gene. Qualitative and quantitative evaluation of the Southern blot patterns showed a deletion of all or part of the RB-1 gene in 15 patients. Deletion hot spots were not detected. The study shows that 16% of germ cell mutations are detectable by Southern blot hybridization, but that densitometric analysis is required in most cases.

Blotting, Southern↗
PubMed1991

Fc receptor blocking antibodies after active immunization for the treatment of recurrent spontaneous abortion.

In a prospective study 140 couples who had at least three spontaneous abortions (RSA) were studied for the presence of Fc receptor blocking antibodies detected by the erythrocyte antibody rosette inhibition (EAI) assay, for anti-paternal cytotoxic antibodies (APCA), and for mixed lymphocyte culture inhibiting (MLCI) antibodies before and after active immunization with paternal lymphocytes. The comparative analysis revealed the EAI assay to possess a higher sensitivity than the APCA and/or MLCI tests in monitoring the specific immune response after active immunization. The success of pregnancy in EAI positive post-immunization patients was not influenced by the presence or absence of APCA or MLCI. In the light of a successful pregnancy outcome of 85.7% (n = 37) in this study we conclude that the monitoring of Fc receptor blocking antibodies is useful in active immunization protocols for RSA patients.

Abortion, Habitual↗
PubMed1991

Microcephalic osteodysplastic primordial dwarfism type I/III in sibs.

The clinical and radiological findings in a pair of sibs with microcephalic osteodysplastic primordial dwarfism (MOPD) are described, a boy who survived for 5 1/2 years and his more severely affected younger sister, who died at the age of 6 months. Neuropathological studies in this girl showed marked micrencephaly with severely hypoplastic, poorly gyrated frontal lobes and absent corpus callosum. Our observation supports the hypothesis that types I and III MOPD probably constitute a spectrum of one and the same entity and published data together with this report are consistent with autosomal recessive inheritance. The pathogenesis of this condition is as yet unknown, but its characteristics indicate a basic defect affecting cell proliferation and tissue differentiation.

Dwarfism↗
PubMed1991

Bloom's syndrome: the German experience.

Ten patients with Bloom's syndrome observed in Germany during the last 20 years are described. They were born between 1964 and 1986. Seven are alive at the age of 8 to 27 years. Three have died at the age of 5 years (acute leukemia), 18 years (pulmonary fibrosis and bronchiectasis), and 21 years (Hodgkin lymphoma and subsequently leukemia). All show the characteristic clinical and cellular phenotype. In addition to the known early occurrence of malignancies, certain behavioral patterns, the occurrence of hyper- and hypopigmented areas in the skin, pulmonary manifestations, and exquisite sensitivity to chemotherapy and probably also to radiotherapy are emphasized. The potential usefulness of bone marrow preservation for later use in autologous transplantation has not yet been determined. Several features of Bloom's syndrome can be understood on the basis of a genetically determined high rate of somatic recombination.

Adolescent↗
PubMed1990

Possible involvement of the retinoblastoma gene in undifferentiated sinonasal carcinoma.

Retinoblastoma tumor formation is initiated by the loss of function of both alleles of the RB-1 gene on chromosome 13. Patients with the hereditary form of retinoblastoma carry a germ line mutation at one of the two homologous gene loci in all cells and have an increased risk for nonocular tumors (mainly osteosarcoma and other mesenchymal tumors) in later life. The authors studied a 38-year-old patient with sinonasal undifferentiated carcinoma (SNUC) who had been treated for bilateral retinoblastoma by enucleation (left eye) and irradiation (right eye), respectively. Using molecular probes for the RB-1 gene and other loci on chromosome 13, the authors detected a deletion at the RB-1 locus in metastatic SNUC cells that was not present in normal tissue. These findings indicate that somatic mutations at RB-1 locus may be involved in the formation or progression of ectodermal tumors.

Adolescent↗
PubMed1990

Further characterization of the EAI factor induced by alloimmunization for treatment of recurrent abortion.

In order to remove the EAI "blocking" activity, EA inhibition positive sera from patients with recurrent abortions were absorbed after alloimmunization with paternal lymphocytes by the lymphoblastoid cell line (LCL) of the husband. To avoid non-specific binding via the Fc-receptor, the cells were first fixed with 0.05% glutaraldehyde. Absorption was performed for 3 h at 4 degrees C. For subsequent elution, the cells were incubated with 0.1 M glycine-HCl, pH 2.3, for 30 min at 4 degrees C. After each step, EAI assay was carried out to determine the "blocking" activity in the supernatants. Furthermore, 10% SDS-PAGE and immunoblotting with goat antihuman IgG of the whole serum and the supernatants were performed. The results obtained give evidence that the EAI "blocking" activity can be absorbed by and eluted from the LCL of the immunizing husband, and is due to an IgG antibody directed against an antigen present on the LCL. Further absorption experiments with trophoblast cells will show whether this antigen is also displayed by the trophoblast.

Abortion, Habitual↗
PubMed1990

Microdissection of the Prader-Willi syndrome chromosome region and identification of potential gene sequences.

The Prader-Willi syndrome chromosome region on the long arm of human chromosome 15 was microdissected and microcloned from 20 GTG-banded metaphase chromosomes, and 5000 recombinant clones were obtained. Of these clones, 39% identify single-copy human DNA sequences, most of which map to the dissected chromosome region and are evolutionarily conserved in other species. Three of eleven clones studied in detail are deleted in several patients with Prader-Willi syndrome. The microclones will be useful for the physical characterization of the Prader-Willi syndrome chromosome region and the identification of the affected genes in this disease.

Adult↗