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PubMed2003

The meiotic drive system on maize abnormal chromosome 10 contains few essential genes.

In maize, a distal portion of abnormal chromosome 10 (Ab10) causes the meiotic drive of itself as well as many unlinked heterochromatic regions known as knobs. The Ab10 drive system, which encodes trans- as well as cis-acting components, occupies a large region of chromosome 10L equivalent to approximately 3% of the genome. Here we describe five new structural mutations of Ab10 (five deletions and a duplication) that arose from a screen for meiotic drive mutants. The high frequency of breakage events, detected both genetically and cytologically, suggest that the chromosome may be especially unstable. Very large deletions within the drive system are female-transmissible and plants homozygous for deficiencies lacking much of this interval can be grown to maturity. The data suggest that few genes required for normal growth and development lie within the portion of Ab10 responsible for meiotic drive. These and other published data suggest that meiotic drive systems tend to evolve in gene-sparse or otherwise information-poor regions of the genome where they are less likely to negatively affect individual fitness.

Chromosome Aberrations↗
PubMed2000

Uneven frequencies of secondary chromosomal abnormalities in acute myeloid leukemias with t(8;21), t(15;17), and inv(16).

The types and incidences of secondary chromosomal abnormalities were analyzed in three subtypes of leukemia with recurrent abnormalities, translocations t(8;21), t(15;17), and inversion inv(16). The main types of clonal secondary abnormalities were similar to those described in the literature, loss of sex chromosome associated with t(8;21), trisomy 8 with t(15;17), and trisomies 8 or 22 with inv(16). On the whole, the incidence of clonal abnormalities was significantly higher in t(8;21) leukemia than in the two other subtypes. This difference was not related to a chromosomal instability peculiar to this leukemia subtype, because the incidence of nonclonal abnormalities was the same in the three types of leukemia studied. The significance of secondary clonal abnormalities remains speculative. A careful comparative analysis of structural rearrangements of the chromosomes usually involved in secondary abnormalities must be carried out as a first step to identify the key genes altered.

Acute Disease↗
PubMed1990

Nutritional folate-deficiency in Chinese hamster ovary cells. Chromosomal abnormalities associated with perturbations in nucleic acid precursors.

Folate deficiency is known to induce chromosomal abnormalities. We used a nutritionally folate-deficient Chinese hamster ovary (CHO) cell culture system to examine modulation of chromosome damage by purine or pyrimidine supplementation. The cells were cultured in folate-deficient (Fol-) medium or Fol- medium supplemented with thymidine (dT) or hypoxanthine (Hx) until population growth arrest. The cultures were then switched to complete medium, permitting the cells to begin cell division. Cell-cycle progression was followed by flow cytometry to identify the first mitosis, when samples for analysis were collected. The mitotic index, frequency of chromosomal aberrations in mitotic cells, and relative distribution of different types of aberrations were determined. Cells grown in Fol- medium supplemented with Hx entered the G2/M phase of the cell cycle at 14 hours after media change as compared with 16 hours for Fol- cultures or 24 hours for Fol- cultures supplemented with dT. Cells cultured in Fol- medium alone or supplemented with dT showed similar frequencies of damage, averaging 20-22%, as compared with 2% for control cultures. In contrast, cells grown in Hx-supplemented medium exhibited a lower frequency of damaged mitoses (15%), as well as a reduction in certain types of abnormalities. This latter finding is surprising in light of our previous work showing that the presence of Hx during folate deficiency produced a more severe perturbation of phenotype (cellular enlargement) and growth control (S-phase delay and cell killing) than did dT supplementation or the absence of both nucleotide precursors.

Animals↗
PubMed1998

Comparison of comparative genomic hybridization with conventional karyotype and classical fluorescence in situ hybridization for prenatal and postnatal diagnosis of unbalanced chromosome abnormalities.

The comparative genomic hybridization (CGH) technique was initially used for detection of chromosomal imbalances in tumor cells. CGH can also be used as a supplementary method to karyotypic analysis in clinical cytogenetic cases. In order to evaluate CGH usefulness in prenatal and postnatal analysis of whole chromosome and segmental aneusomies, we investigated 13 clinical samples from blood, cultured chorionic villi, cultured amniotic fluids and uncultured amniotic fluids. These specimens, initially analyzed by conventional cytogenetics, included 5p monosomy, 9p duplication, add 6p, unbalanced translocation between chromosomes 5 and 10, mosaic tetrasomy 12p (50%), unbalanced (X;X) translocation and Prader-Willi deletion (15q11-13). In addition, six numerical chromosome aberrations (tetrasomy X, trisomies 13, 18, 21 and monosomy X) were analysed. All the chromosomal abnormalities, except the Prader-Willi deletion, were correctly detected by CGH. Here, we have demonstrated that the CGH technique is an alternative to classical fluorescence in situ hybridization using specific probes for detection of the unbalanced chromosomal aberrations in prenatal and postnatal diagnosis and could be used for rapid prenatal screening for unbalanced aberrations.

Amniotic Fluid↗
PubMed2001

Characterization of chromosomal abnormalities in uroepithelial carcinomas by G-banding, spectral karyotyping and FISH analysis.

Chromosome analysis by G-banding, spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) was performed on 24 short-term cultured transitional cell bladder carcinomas and 5 cell lines established from bladder carcinomas. Except for one tumor with an apparently normal chromosomal constitution, clonal chromosome abnormalities were detected in all examined cases by the combined approach. The application of SKY and FISH techniques improved the karyotypic descriptions, originally based on G-banding only, by identifying 32 additional numerical changes, by establishing the chromosomal origin of 27 markers and 2 ring chromosomes, by redefining 53 aberrations and by detecting 15 hidden chromosomal rearrangements. No recurrent translocation, however, was detected. The most prominent karyotypic feature was thus the occurrence of deletions and losses of whole chromosome copies indicating the importance of tumor suppressor genes in transitional cell carcinoma pathogenesis. Invasive carcinomas were karyotypically more complex than were low grade superficial tumors. Specific losses of material from chromosome 9 and from chromosome arms 11p and 8p, and gains of 8q and 1q seem to be early changes appearing in superficial tumors, whereas losses from 4p and 17p and the formation of an isochromosome for 5p were associated with more aggressive tumor phenotypes.

Aged↗
PubMed1979

Derangement of neuronal migration in a child with multiple congenital anomalies, two congenital neoplasms, without apparent chromosomal abnormalities.

A live-born male infant with multiple severe abnormalities, two congenital neoplasms, a neuroblastoma and nephroblastoma, and without apparent chromosomal abnormalities, is described. The neuropathologic findings were a holoprosencephalic type defect with disturbance of neuronal migration to the cortical plate. Comparison of the overall findings with cases presenting similar multiple congenital abnormalities indicates that this case either demonstrates previously unrecognized features of these syndromes, or is unique.

Abnormalities, Multiple↗
PubMed1998

Cytogenetic characterization of an extra structurally abnormal chromosome associated with severe mental retardation: inv dup (15) (q13).

We have studied an extra structually abnormal chromosome (ESAC) in a 13 years old boy with profound mental, psychomotor and speech retardation, behavioral problems, seizures and abnormal electroencephalogram. The examination of the bisatellited ESAC with chromosome banding demonstrated that the karyotype was: 47, XY, +inv dup (15) (pter-->q13::q13-->pter). The cytogenetic characterization of the inv dup (15) is reported with special emphasis on the usefulness of DA/DAPI staining when G-banding is sequentially performed to discard possible heteromorphisms in DA/DAPI positive chromosomes, and the importance of Ag-NOR heteromorphisms to ascertain the maternal origin of the inv dup (15). A U-type exchange between two non-sister chromatids is proposed as its mechanism of formation. The clinical features of the case were consistent with those previously reported in similar cases.

Adolescent↗
PubMed2003

Sequence-based, in situ detection of chromosomal abnormalities at high resolution.

We developed single copy probes from the draft genome sequence for fluorescence in situ hybridization (scFISH) which precisely delineate chromosome abnormalities at a resolution equivalent to genomic Southern analysis. This study illustrates how scFISH probes detect cryptic and subtle abnormalities and localize the sites of chromosome rearrangements. scFISH probes are substantially shorter than conventional recombinant DNA-derived probes, and C(o)t1 DNA is not required to suppress repetitive sequence hybridization. In this study, 74 single copy sequence probes (>1,500 bp) have been developed from >/=100 kb genomic intervals associated with either constitutional or acquired disorders. Applications of these probes include detection of congenital microdeletion syndromes on chromosomes 1, 4, 7, 15, 17, 22 and submicroscopic deletions involving the imprinting center on chromosome 15q11.2q13. We demonstrate how hybridization with multiple combinations of probes derived from the Smith-Magenis syndrome interval on chromosome 17 identified a patient with an atypical, proximal deletion breakpoint. A similar multi-probe hybridization strategy has also been used to delineate the translocation breakpoint region on chromosome 9 in chronic myelogenous leukemia. Probes have also been designed to hybridize to multiple cis paralogs, both enhancing the chromosomal target size and detecting chromosome rearrangements, for example, by splitting and separating a family of related sequences flanking an inversion breakpoint on chromosome 16 in acute myelogenous leukemia. These novel strategies for rapid and precise characterization of cytogenetic abnormalities are feasible because of the sequence-defined properties and dense euchromatic organization of single copy probes.

Adult↗
PubMed1996

Sex chromosome abnormalities in lung cancer patients.

Chromosomal analyses of lymphocytes from lung cancer patients and normal subjects revealed that the X and the Y chromosomes have both structural and numerical abnormalities in higher frequency in patients compared to the controls. These abnormalities included chromatid/isochromatid breaks, translocations, ring formation, and selective nondisjunctions, resulting in multisomies of either the X or Y chromosomes. Possible significance of these genetic abnormalities are discussed in relation to lung cancer patients.

Adult↗
PubMed1998

Solitary enchondroma with clonal chromosomal abnormalities.

We report a case of a solitary enchondroma located in the head of the left fibula in a 50-year-old patient and present the findings of histopathologic investigation and cytogenetic analysis. The tumor revealed simple karyotypic abnormalities with t(8;17)(q23;p13) and loss of chromosomes 9, 19, and 22 as clonal chromosomal changes. Only a few enchondromas with chromosome aberrations have been published previously; nevertheless, it appears that benign and malignant cartilaginous tumors may have similar chromosomal abnormalities.

Bone Neoplasms↗
PubMed1997

Chromosome abnormality in solid and cystic tumor of the pancreas.

We report a case of a solid and cystic tumor of the pancreas with chromosomal abnormalities. The patient, a 13-yr-old girl, successfully underwent surgical excision and has been asymptomatic for more than 10 months. The tumor had two parameters suggesting malignant potential; a local invasion into a bile duct, and high mitotic activity. Chromosomal analysis showed two complex abnormalities, of which double loss of X chromosomes and trisomy for chromosome 3 were common. The complexity and polyclonality may stem from a clonal evolution. The observed abnormalities may provide a crucial clue to the understanding of the developmental process of this neoplasm.

Adolescent↗
PubMed1990

Direct analysis of uncultured cytotrophoblastic cells from second- and third-trimester placentas: an accurate and rapid method for detection of fetal chromosome abnormalities.

Transabdominal chorionic villus sampling can be readily used for detection of fetal chromosome abnormalities in the second and third trimesters of pregnancy. Although culture of chorionic villi offers little advantage over cultured amniotic fluid cells with respect to time required to obtain results, cytogenetic analysis of chorionic villi by direct analysis of uncultured cytotrophoblastic cells offers clear advantages because of the very short time required to obtain results. To determine whether direct analysis of uncultured cytotrophoblastic cells from second- and third-trimester placentas can routinely provide rapid and accurate assessment of fetal status, we evaluated chorionic villus specimens obtained from 57 placentas; 49 placentas were sampled in the second trimester whereas eight were sampled in the third trimester. Direct preparations yielded karyotypes in 56 (98.2%) preparations; all results of direct analyses were available within 72 hours and, when requested, within 12 hours. All results were confirmed by chromosome analysis of cultured mesenchymal core cells or cultured fetal tissue. We conclude that direct analysis of cytotrophoblastic cells from second- and third-trimester placentas is a very rapid and accurate method for determining fetal chromosome status that is comparable with, if not superior to, percutaneous umbilical blood sampling.

Adult↗
PubMed2000

Distinct chromosomal abnormality pattern in primary liver cancer of non-B, non-C patients.

To discriminate among the chromosomal abnormalities associated with the etiology of hepatocellular carcinoma (HCC), we performed a comparative genomic hybridization (CGH) analysis on 34 HCCs resected on non-cirrhotic livers from patients serologically negative for both hepatitis B (HBV) and C (HCV) viruses. The results were compared to those of a previous analysis of 50 HCCs selected on the basis of their positivity for HBV infection. The majority of the abnormalities found in the HBV positive cases (losses of chromosome arms 1p, 8p, 6q, 13q and 14q and gains of 1q, 8q, 6p and 17q) were similarly detected in the virus negative specimens. In contrast, a significant decrease (40% on average) was observed for losses at 4q, 16q and 17p in non-viral HCC samples, suggesting that these abnormalities are tightly associated with HBV infection. Thus, in addition to a common pathway towards malignancy, a subset of alterations may preferentially contribute to virus-induced carcinogenesis. In a parallel CGH study of 10 fibrolamellar carcinomas, a rare subtype of HCC, we found in six out of the seven informative cases, gains of chromosome arm 1q. This region, which is also preferentially amplified in non fibrolamellar tumors (58%), may contain an essential proto-oncogene commonly implicated in liver carcinogenesis.

Adolescent↗
PubMed1993

Neuropsychological impairment in 42 adolescents with sex chromosome abnormalities.

Sixty-seven adolescents participated in this protocol, including 42 with sex chromosome abnormalities and 25 controls. Results from a battery of neuropsychological tests indicated karyotype specific patterns of neuropsychological impairment: (1) 47,XXY boys had unimpaired intelligence but reduced abilities in verbal fluency and reading; (2) 47,XXX girls experienced reduced general intelligence accompanied by impaired scores on individual tests of attention, concept formation, spatial thinking, verbal fluency, and academic skills, while retention of memorized information was a relative strength; (3) among the 45,X girls average intelligence level was also reduced along with scores on tests of attention, concept formation, verbal fluency, spatial thinking, and academic skills, and an atypical pattern of hand dominance was identified; (4) test scores in the group of mosaic females did not differ from those of controls. Test scores and patterns of personal adaptation were quite variable in all groups; while eight nonmosaic propositi required intensive special education assistance in their public schooling, eight others have attended college.

Adaptation, Psychological↗
PubMed1999

Psychosocial competence of unselected young adults with sex chromosome abnormalities.

Very little is known about the adult adaptation of individuals with sex chromosome abnormalities (SCA) except for a few reports based upon biased samples of clinically identified patients. This first report from the Denver SCA study on the adult psychosocial adaptation of 36 unselected propositi, identified at birth, shows a continuation of mild psychological and social problems. Psychiatric interviews and self-reported information revealed that adaptation is quite variable, with many of the nonmosaic propositi not faring as well as their siblings, but in a few instances exceeding the success of brothers and sisters. Within this group of SCA subjects a subset demonstrated more marked pathology and a tendency to over-rate their social adaptation relative to the psychiatric interviewer, suggesting that the exclusive use of self-report questionnaires may not provide accurate assessment of psychological characteristics in this and other special populations. The full adult SCA behavioral phenotype has not yet been established but is emerging through additional reports from this and other studies of unselected SCA adults.

Adaptation, Psychological↗
PubMed2002

Parental decisions of prenatally detected sex chromosome abnormality.

Because of the widespread use of amniocentesis, the prenatal recognition of sex chromosome abnormality (SCA) has become increasingly common. Recent literature provided an insight into the understanding of the natural history and prognosis for individuals with SCA. Our study was designed to review the parental decision on pregnancy with SCA. Over the last 10 yr, we diagnosed 38 cases (0.50%) with SCA out of 7,498 prenatal cases. We reviewed the records and the results of the pregnancies. We included the cases (n=25) of apparently normal anatomic fetus to analyze the factors influencing parental decision. We excluded 13 cases with obvious anomaly or presumably bad outcome. Fifteen (60%) couples continued their pregnancies and ten (40%) terminated theirs. Nine couples (64%) out of fourteen mosaicism cases continued their pregnancies. All five pregnancies assisted by reproductive technique continued their pregnancies. More pregnancies were continued when counseling was done by an MD geneticist rather than by an obstetrician. A significant trend was observed with a higher rate of pregnancy continuation in recent years. The genetic counseling is important to give appropriate information to the parents. Establishing guidelines and protocols will help both obstetricians and parents to make a decision.

Chromosome Aberrations↗
PubMed1975

[Tetratospermia and chromosome abnormalities].

Human semen in two chromosomal abnormalitie cases presents one important increase of small, large and double head spermatozoa. Findings of this type of abnormal sperm morphology must be include chromosome analysis in the subfertile couple investigations.

Chromosome Aberrations↗
PubMed1988

Cardiac defects in chromosomally abnormal human embryos of 10-14 weeks' gestation.

Cardiac defects were studied in five chromosomally abnormal embryos of 10-14 weeks' gestation by free-hand microdissection of hearts measuring 2.5-6 mm in diameter. The type of cardiac malformation alone or in association with other anomalies helped to confirm the chromosome diagnosis established prenatally by chorionic villus sampling or after spontaneous abortion. It was suggestive of a chromosomal disorder in one case in which cytogenetic investigation had failed.

Adult↗