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C M Tuck-Muller

Publications and source records attributed to C M Tuck-Muller.

33 records · Page 2Linked to original sources
PubMed1993

A complex chromosomal rearrangement detected prenatally and studied by fluorescence in situ hybridization.

We report of case of a complex chromosomal rearrangement detected prenatally and studied with traditional banding methods and fluorescence in situ hybridization. The combination of these techniques showed that four chromosomes were involved in the translocation. Nine breakpoints were proposed to explain these results. Some of the findings could only be detected with fluorescence in situ hybridization, demonstrating the usefulness of this technique in characterizing chromosomal abnormalities that would otherwise be difficult to interpret correctly with classical cytogenetics alone.

Adult↗
PubMed1993

Fertility and the cri du chat syndrome.

We describe a mother and daughter with typical cri du chat syndrome. Previous investigators have noted the lack of information about the reproductive fitness of patients with this disorder. This report demonstrates that females with cri du chat syndrome are fertile, can gestate and likewise deliver affected offspring, which has significant management and counseling implications.

Adult↗
PubMed1993

Cytogenetic survey in systemic sclerosis: correlation of aneuploidy with the presence of anticentromere antibodies.

Previous cytogenetic studies of patients with systemic sclerosis have obtained conflicting results regarding the presence of chromosomal anomalies. We studied 38 patients and 15 controls to determine whether these inconsistencies were due to differences in the subgroups of patients who were studied. Because many patients with systemic sclerosis produce autoantibodies to protein antigens that have been implicated in chromosome structure and function, we further hypothesized that the presence of these autoantibodies might correlate with the presence of chromosomal anomalies. Patients were classified into clinical subgroups based on the extent of their disease. Their sera were assayed for autoantibodies to topoisomerase I and centromere proteins (CENP-A, CENP-B, and CENP-C) by immunoblotting. Cytogenetic analyses for aneuploidy and chromosome breaks were performed. Anticentromere antibody positive (ACA+) patients had significantly more aneuploidy than either ACA negative (ACA-) patients or controls (P = 0.041). Although the patient group, when considered as a whole, had significantly greater aneuploidy than the control group (P < 0.005), patients who were ACA--did not have more aneuploidy than the controls had. Patients with Type I disease (sclerodactyly), the majority of whom were ACA+, also had significantly more aneuploidy than did either the controls or patients with Type III (diffuse) disease, most of whom were ACA- (P < 0.005). ACA+ patients also had more chromatid breaks than the controls had (P < 0.05). The correlation between the presence of ACAs and chromosomal aneuploidy suggests that aneuploidy may be the result of nondisjunction secondary to centromeric dysfunction. In support of this hypothesis, the ACA+ patients who had antibodies to CENP-C exhibited more chromosomal aneuploidy than did either anti-CENP-A or anti-CENP-B positive patients (P < 0.048). Unlike CENP-A and CENP-B, which are present at both functional and inactivated centromeres, CENP-C is present at the kinetochore of functional centromeres.

Adult↗
PubMed1992

Cancer susceptibility in ataxia-telangiectasia.

Ataxia-telangiectasia (A-T) is a syndrome that has an extremely high incidence of cancer. Patients with the disease are homozygous for a mutant gene, the A-T gene, located at 11q23. Of these individuals, 30-40% develop cancer. Of these cancers, 80% are lymphoid. Those heterozygous for the A-T gene also have an increased frequency of cancer, the most notable being the 6.8-fold increase of breast cancer in females carriers. The syndrome is characterized cytogenetically by increased nonrandom chromosome breaks and rearrangements in lymphocytes involving the sites of the immunoglobulin and T-cell receptor genes. Clones of cells having the same rearrangements are often present in the blood of the A-T patients and if the rearrangements involve certain sites, especially a locus within 14q32, the propensity to progress to a malignant transformation is great. Sequencing the A-T gene and ascertaining its function should contribute significantly to our understanding of the molecular mechanisms underlying cancer susceptibility.

Ataxia Telangiectasia↗
PubMed1991

Studies of mitotic and centromeric abnormalities in Roberts syndrome: implications for a defect in the mitotic mechanism.

Roberts syndrome is an inherited human condition that is of particular interest because separation of centromeres and constitutive heterochromatin is observed in metaphase chromosomes. In this study we investigated the frequency of other cytological abnormalities in three Roberts syndrome patients. Our findings when taken with previous cytological reports emphasize that there are other features that are equally characteristic of Roberts syndrome: (1) aneuploidy with random chromosome loss and (2) micronuclei and/or nuclear lobulations of 8%-24% of interphase cells. We observed abnormal chromosome movement involving one or all the chromosomes during anaphase. Evidence is presented suggesting that aneuploidy, micronuclei and abnormal nuclear morphology are a direct result of lagging chromosomes. The cytological features documented for Roberts syndrome indicate that this is a human mitotic mutant.

Abnormalities, Multiple↗
PubMed1990

Evidence for involvement of a Robertsonian translocation 13 chromosome in formation of a ring chromosome 13.

We have used molecular and cytogenetic methods to study the derivation of a ring chromosome 13 in the fetus of a woman mosaic for a translocation chromosome 13. DNA analysis showed that the translocation chromosome was a Robertsonian translocation, not an isochromosome. We suggest that the ring is derived from the translocation chromosome by breaks in both long arms and subsequent reunion, r(13) (q12q14).

Abnormalities, Multiple↗
PubMed1989

Correction of sphingomyelinase deficiency in Niemann-Pick type C fibroblasts by removal of lipoprotein fraction from culture media.

The average sphingomyelinase activity of fibroblasts obtained from 12 Niemann-Pick type C patients was 37.9% of that of normal fibroblasts (27.2 versus 72 nmol (mg protein)-1 h-1) when the cells were cultured in minimum essential medium containing 13% fetal bovine serum. Following replacement of the above medium with medium in which the lipoprotein fraction had been removed from the fetal bovine serum, the sphingomyelinase activity rose over a 7-day period from about 1/3 of normal to normal or above. Upon reintroduction of medium containing 10% fetal bovine serum which had not been extracted, the sphingomyelinase activity of the Niemann-Pick type C cells again fell within 48 h to 30% of the normal controls. In contrast, cell lines from patients with either Niemann-Pick Type A or B were not influenced by the presence or the absence of lipoprotein, i.e. lacked sphingomyelinase activity under all culture conditions examined. Histochemical staining with filipin showed an inverse relationship between the sphingomyelinase activity and intracellular, free, unesterified, cholesterol level. Moreover, immunochemical staining with an antibody against a lysosomal membrane protein provided direct evidence that the accumulation of unesterified cholesterol in cells cultured in regular (non-extracted) medium occurred within lysosomes and/or related organelles.

Cells, Cultured↗
PubMed1988

Association of a new chromosomal deletion [del(1)(q32q42)] with diaphragmatic hernia: assignment of a human ferritin gene.

A newborn male with a large diaphragmatic hernia presented in severe respiratory distress. Additional features included a paucity of subcutaneous tissue, mild facial dysmorphism, webbing of the neck, genital hypoplasia, and flexion contractures of the fingers. His karyotype showed a previously unreported de novo interstitial deletion of the long arm of chromosome 1 [46,XY,del(1)(pter----q32.3::q42.3----qter)]. Regional mapping of five human genes that have been provisionally assigned to chromosome 1 was performed by restriction analysis of genomic DNA from this patient. Glucocerebrosidase, H4 histone, renin, and alpha-spectrin genes mapped outside the deleted region, whereas an H subunit of the ferritin gene mapped to 1q32----q42. These results indicate the utility of chromosomal deletions in gene mapping, and the importance of karyotype analysis in newborns with diaphragmatic hernias.

Chromosome Banding↗
PubMed1987

Autosomal dominant congenital cataract associated with chromosomal translocation [t(3;4)(p26.2;p15)].

We studied a family in which congenital cataracts were found in a father and son who had a reciprocal translocation between the short arms of chromosomes 3 and 4 [t(3;4)(p26.2;p15)]. The father's parents and brother had normal chromosomes and no evidence of cataracts. While results of these studies do not prove a causal relationship, they do strongly suggest that the areas near the break points involved in the translocation (3p26.2 and 4p15) would be good sites for further investigations into the genetic basis of this type of cataract.

Cataract↗
PubMed1986

Chromosome studies in 10 patients with the Rett syndrome.

Chromosomes of white blood cells from 10 girls with the Rett syndrome, 9 of their mothers and 17 unrelated controls (5 girls and 12 women) were examined for the presence of the fragile site on Xp22 under different culture conditions. Six of the 10 Rett patients were fra(X)(p22) positive while 4 failed to express this fragile site. In the 6 patients expressing the fragile site it was present in 1 to 3% of all cells. Similarly, 5 of the mothers and 6 of the control women showed this fragile site, with a frequency of 1 to 9%. Concordance analysis showed that in the 9 mother-daughter pairs examined, 5 had concordant results while 4 of the pairs were discordant. These findings are very similar to those found in non-Rett individuals by ourselves and other investigators. These data agree with published findings that fra(X)(p22) is a common fragile site in normal individuals. Therefore, we conclude that the incidence of the Xp22 fragile site in the Rett syndrome does not differ from that found in various non-Rett individuals, including normal persons. This indicates to us that fra(X)(p22) cannot serve as a chromosomal marker for the Rett syndrome.

Adult↗
PubMed1984

NOR associations with heterochromatin.

Associations between nucleolus organizer regions (NORs) and non-acrocentric chromosomes were scored in 2,800 metaphase spreads from PHA-stimulated lymphocyte cultures (48 h) from 14 individuals. The preparations were both silver stained and C-banded. In order to calculate the expected values for associations, the ratio of heterochromatin length to euchromatin length was established for each subject. Individual C-band lengths and centromeric lengths were also determined. When silver connective (SC) associations with heterochromatin were compared to SC associations with euchromatin, the number of associations with heterochromatin was significantly greater than expected (P less than 0.000001) for each subject. The SC associations were not distributed randomly over the heterochromatin of the non-acrocentrics. Chromosomes 1 and 2 had significantly more than expected. Chromosomes 17, 18, 19, 20, and the Y had fewer than expected. NOR associations with euchromatic segments also showed a nonrandom pattern of distribution.

Chromosome Banding↗
PubMed1984

A method for combined C-banding and silver staining.

A reliable technique for combined C-banding and silver staining of metaphase chromosomes which uses trypsinization is described. Slides are first immersed in dilute HCl to remove residual cytoplasm from around the chromosomes. They are then treated with saturated barium hydroxide and incubated overnight in saline sodium citrate (0.30 M NaCl, 0.03 M sodium citrate, adjusted to pH 7.0 with HCl). Following the C-banding pretreatment, a two-step method of silver staining which employs a protective colloidal developer is used to stain the nucleolar organizer regions (NORs) of the chromosomes. Silver staining is followed by trypsinization to remove extraneous silver precipitate from the chromosome arms which permits the C-bands to be stained with Giemsa. The method works equally well with fresh and aged mitotic chromosome preparations and gives consistent staining of both heterochromatin and active NORs in metaphases across the slide.

Chromosome Banding↗
PubMedDate not supplied

Partial trisomy 7p defined by analysis of a complex chromosome rearrangement using a BAC clone panel.

PURPOSE: To illustrate the use of bacterial artificial chromosome (BAC) clone panels for molecular cytogenetic analysis of complex chromosome rearrangements (CCRs). METHODS: High resolution cytogenetics followed by fluorescence in situ hybridization (FISH) analysis using chromosome band-specific BAC probes, in addition to commercially available probes. RESULTS: High resolution cytogenetics in conjunction with FISH using commercially available probes proved inadequate to resolve problems in characterizing a balanced CCR in the mother of a patient who had inherited an unbalanced form of the CCR. Accurate interpretation of the CCR and the unbalanced rearrangement in the patient as trisomy 7p12.2-->p21.3 was accomplished only through use of the BAC clone panel. CONCLUSION: Use of BAC clone panels can enhance the power of FISH analysis in defining chromosome rearrangements that cannot be resolved by high resolution chromosome analysis.

Adolescent↗