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Biomedical subjects

W R Breg

Publications and source records attributed to W R Breg.

At least 55 records · Page 3Linked to original sources
PubMed1980

H-Y antigen in X,i(Xq) gonadal dysgenesis: evidence of X-linked genes in testicular differentiation.

Three years ago, we detected H-Y antigen in the white blood cells of a phenotypic female with several of the stigmata of Turner's syndrome, and the mosaic karyotype: 45,X/46,X,i(Xq). We surmised at the time that the isochromosome, i(Xq), may have contained occult Y-Chromosome-derived material. We have now confirmed the presence of H-Y in this patient and we have obtained evidence for the presence of H-Y in four of five other similar patients, all of whom are notable for carrying at least a single cell line with the karyotype 46,Xi(Xq). Although we cannot categorically exclude the presence of Y-chromosomal genes in the cells of these patients, there is no cytogenetic evidence of structural rearrangement involving the Y in any of the cases. Expression of H-Y structural genes are X-situated, or alternatively that they are autosomal and X-regulated. It would follow that the H-Y+ cellular phenotype per se is not a valid marker for the Y-chromosome, and that H-Y genes that have been mapped to the pericentric region of the Y may be regulatory.

Adolescent↗
PubMed1980

Human X chromosomes: synchrony of DNA replication in diploid and triploid fibroblasts with multiple active or inactive X chromosomes.

We have analyzed patterns of DNA replication in X chromosomes from diploid cultured human fibroblasts and from three triploid 69,XXY fibroblast strains, using BrdU--33258 Hoechst--Giemsa techniques. Both X chromosomes in each of these Barr body-negative triploid strains were early-replicating. The results of gene dosage studies using (1) a histochemical stain to measure X-linked glucose-6-phosphate dehydrogenase (G6PD) activity in single cells and (2) cellulose acetate electrophoresis of G6PD activity in cell extracts also indicated that both Xs in these strains were genetically active. When we compared the synchrony of X chromosome DNA replication kinetics both between cells and within cells containing multiple inactive Xs, a marked variability and asynchrony was observed for late-replicating X chromosomes. In a culture of 47,XXX fibroblasts administered an 8-h terminal pulse of dT after growth in BrdU-containing medium, asynchrony was detected between the two late-replicating Xs in approximately 70% of cells examined. No such asynchrony was observed between the two early-replicating Xs in similarly cultured 69,XXY cells; in the triploid strains, the two Xs were distinguished by asynchronous replication in only approximately 15% of cells. The striking variability in late X chromosome replication kinetics appears, then, to be a property unique to inactive Xs and is not inherent to all X chromosomes.

Aneuploidy↗
PubMed1980

XY gonadal dysgenesis associated with the congenital nephrotic syndrome.

The occurrence of a nephrotic syndrome in a female infant with a 46,XY karyotype is reported. The internal genitalia were female but a microscopic region of immature testicular tissue was present in 1 of 2 streak gonads. The relationship of this child's abnormal genital differentiation to her renal disease is discussed in the light of reported cases of infantile nephritis and Wilms' tumor in male pseudohermaphrodites. It is suggested that a common teratogen operating on the embryonic urogenital ridge may cause both genital and renal anomalies.

Female↗
PubMed1979

Multiple congenital anomalies/mental retardation (MCA/MR) syndrome due to partial 1q duplication and possible 18p deletion: a study of four individuals in two families.

We have evaluated four individuals from two unrelated families with a similar multiple congenital anomalies/mental retardation (MCA/MR) syndrome due to partial duplication of chromosome 1q and possible deletion 18p. In both families the mothers and several relatives were carriers of the balanced translocation rcp t(1;18) (q42;p11). The features which the four have in common are relative macrocephaly, prominent forehead, micrognathia, and highly arched palate; three of the four individuals have short stature, scoliosis, kyphosis, hirsutism, camptodactyly, sacral dimple, repaired inguinal hernias, and eye abnormalities. Reproductive histories of five balanced translocation carriers in these families indicate that they have a high risk of spontaneous abortions and infants with multiple malformations.

Abnormalities, Multiple↗
PubMed1979

Complete and partial trisomy of different segments of chromosome 8: case reports and review.

This report describes some of the clinical, chromosomal and radiological findings in three unrelated patients with trisomy 8 mosaicism syndrome (T8ms), two first cousins with trisomy 8q and a patient with trisomy 8p. On the basis of the phenotypic and cytogenetic findings seen in our six patients and those noted in previous reports, we concur with Riccardi & Crandall (1978) that most physical malformations seen in T8ms are associated with trisomy for the long arm of chromosome 8.

Abnormalities, Multiple↗
PubMed1979

Loss of Rh antigen associated with acquired Rh antibodies and a chromosome translocation in a patient with myeloid metaplasia.

Myeloid metaplasia is a clonal disease of the marrow pluripotent stem cell in which a constant cytogenetic abnormality could result in an altered antigenic characteristic of hematopoietic cells. A 57-yr-old man who had acquired myeloid metaplasia at age 37 was noted to be Rh negative, although blood typing at age 33 was Rh positive. His erythrocytes reacted with anti-c and anti-e, typical for an Rh negative individual. Analysis of 11 metaphase bone marrow cells by G-banding revealed 46 chromosomes with a consistent anomaly in 100% of cells involving chromosomes 1 and 13. The changes were consistent with a reciprocal translocation, with break points at approximately 1p32 and 13q22, although break points at 1p13 and 13q14 were also possible. Since previous cytogenetic data have localized the Rh gene to the short arm of chromosome 1, our data indicate the Rh gene lies within the segment u13 leads to 1p32. Serum of this patient had circulating anti-D and anti-C antibodies. Consequently, this patient lost immunologic tolerance to a "self antigen" after losing the ability to express this antigen.

Chromosome Mapping↗
PubMed1979

Fanconi's anemia: the preanemic phase.

Anticipation of Franconi's anemia prior to the development of overt marrow aplasia may prevent some morbidity and mortality from infectious and hemorrhagic complications. A presumptive diagnosis was made in a firstborn child and radial anomalies, small size, elevated fetal hemoglobin, intermittent excessive chromosome breakage and elevated T-antigen expression in fibroblasts infected with Simian virus 40. Serial studies may help identify infants and young children at risk to develop this type of constitutional marrow hypoplasia.

Anemia, Aplastic↗
PubMed1977

Preferential derivation of abnormal human G-group-like chromosomes from chromosome 15.

The marked binding of antibodies specific for 5-methylcytidine to the short arm of chromosome 15 distinguishes this chromosome from the other human acrocentrics. This method has been used to study over 60 individuals including 12 who did not have Down's syndrome, but who did have an extra G-group sized acrocentric chromosome. In six cases the extra chromosome did not show intensive binding of anti-5-methylcytidine. In the other six cases, the extra chromosome contained a 5-methylcytidine rich band at each end indicating that both ends were derived from chromosome 15 and contained centromeric heterochromatin normally present on the short arm of chromosome 15. The duplication of short arm material in the abnormal chromosomes was confirmed in all cases by quinacrine staining, nucleolar organizer (Ag-AS) staining or C-banding. In three cases, the abnormal chromosome appeared to arise from two different chromosomes 15. Several possible mechanisms for the production of the abnormal chromosome are discussed. The individuals with this abnormal chromosome all showed some degree of mental retardation, but few common physical findings.

Adult↗
PubMed1977

Analysis of human Y-chromosome-specific reiterated DNA in chromosome variants.

A number of individuals with aberrant Y chromosomes have been tested for the presence of Y-chromosome-specific reiterated DNA. These studies locate Y-chromosome-specific reiterated sequences on the long arm of the Y chromosome. Correlation with phenotype and other known Y chromosome markers establish that the Y-chromosome-specific reiterated DNA discussed here has no evident role in male determination.

Base Sequence↗
PubMed1977

7q deletion syndrome (7q32 leads to 7qter).

Four independently ascertained children who presented with unusual facies and delayed mental and physical development were found to have a similar deletion of part of the long arm of chromosome 7 (46,XX or XY, del(7)(q32); 46,XX or XY,del(7)(pter leads to q32:)). Comparison of the findings of these four cases with one other case report of a similar deletion revealed similar dysmorphologic features in all five cases.

Abnormalities, Multiple↗