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PubMedDate not supplied

Contribution of ultrasonographic examination to the prenatal detection of chromosomal abnormalities in 19 centres across Europe.

The objective of this study was to evaluate the prenatal detection of chromosomal abnormalities by fetal ultrasonographic examination in a large database provided by 19 Registries of Congenital Anomalies from 11 European countries. This study included 1738 cases of chromosomal abnormalities, liveborn, stillborn or termination of pregnancy regardless of maternal age from a population of 664,340 births during the period 1996 - 1998. The most frequent chromosomal anomalies were Down syndrome (n=1050), trisomy 18 (n=191), Turner syndrome (n=125), trisomy 13 (n=86), and triploidy (n=56). Fetal ultrasonographic examination resulted in the prenatal detection of 37.7% of the chromosomal abnormalities, thereby resulting in a reduction of 28.6% in their prevalence at birth due to terminations of pregnancy. The detection rate by ultrasound examination varied according to local policies of prenatal diagnosis : it was lower in countries where routine scan were not performed and higher in countries in which at least one routine anomaly scan during the second trimester of pregnancy was performed. The ultrasound detection varied according to the specific chromosomal anomaly and was lowest for Klinefelter syndrome (5.7%) and highest for triploidy (78.6%). For Down syndrome it was 26.4%. Termination of pregnancy was performed in 75.9% of the cases. Among the 655 cases detected by ultrasound, the most frequent ultrasound signs by category of chromosomal abnormalities were analysed. This study shows that ultrasound screening is an important tool in the prenatal detection of chromosomal abnormalities in Europe, leading to a significant reduction in the prevalence of livebirth children with chromosomal anomalies.

Abnormalities, Multiple↗
PubMed1997

[Usefulness of ultrasonographic markers in chromosomal abnormalities].

During a 3 and 1/2 years, 132 pregnancies were diagnosed as having a wide variety of congenital abnormalities. A high resolution ultrasound and multidisciplinary approach was used. In 95 cases fetal karyotyping was made. In this group the incidence of chromosomal abnormalities diagnosed during the period and phenotypic expression of the different types of chromosomal abnormalities was investigated. 29 abnormal karyotypes were found; 11 trisomy 18, 7 in monosomy X, 4 in trisomy 21, 3 in trisomy 13, 1 with tetraploidy (92XXYY), 1 Turner mosaic (45XO 68% 46XY 32%), 2 inversions of choromosome 9. Of the total abnormal chromosomal diagnosed during the period (N = 57), this group represented 49.2%, compared to 5 to 15% found in other risk groups. 224 congenital abnormalities were found. 43 (19%) isolated, and 181 (81%) associated. Of the 224 congenital abnormalities diagnosed, 80 (36%) were associated with chromosomal abnormalities. The most associated markers were duodenal atresia, heart defect, microcephaly, enlarged posterior fossa, and cystic hygromata. A specific markers pattern was found for each aneuploidy; heart defects for trisomy 18, holoprosencephaly and faciel cleft for trisomy 13, and cystic hygromata for monosomy X. It was concluded that the ultasound can be the most useful method to select the group of pregnant women with a higher risk of abnormal karyotype.

Adult↗
PubMed2002

Cellular drug resistance in childhood acute myeloid leukemia is related to chromosomal abnormalities.

Specific cytogenetic abnormalities predict prognosis in childhood acute myeloid leukemia (AML). However, it is unknown why they are predictive and whether this is related to drug resistance. We previously reported that Down syndrome (DS) AML was associated with favorable resistance profiles. Here, we successfully analyzed drug resistance and (cyto-) genetic abnormalities of 109 untreated childhood AML samples using the 4-day total cell-kill methyl-thiazolyl tetrazolium (MTT) assay. Patients were classified according to the genetic abnormalities in the leukemic cells: t(8;21), inv(16), t(15;17), t(9;11), other 11q23 translocations, abnormalities of chromosome 5/7, trisomy 8 alone, normal karyotype, single random, and multiple (defined as 2 or more) abnormalities. The DS AML samples were excluded from the subgroup analysis. Samples with chromosome 5/7 abnormalities were median 3.9-fold (P =.01) more resistant to cytarabine than other AML samples. The t(9;11) samples were more sensitive to cytarabine (median 2.9-fold, P =.002), etoposide (13.1-fold, P =.001), the anthracyclines (2.9- to 8.0-fold, P <.01), and 2-chlorodeoxyadenosine (10.0-fold, P =.002) than other AML samples. The trisomy 8 and t(15;17) groups were too small for meaningful analysis. All other genetic subgroups did not show specific resistance profiles. Overall, we found no differences in drug resistance in samples taken at diagnosis between patients remaining in continuous complete remission (CCR) versus the refractory/relapsed patients. Within several genetic subgroups, however, relapsed/refractory patients were more cytarabine resistant when compared with patients remaining in CCR, but numbers were small and the results were not significant. We conclude that some, but not all, cytogenetic subgroups in childhood AML display specific drug-resistance profiles.

Acute Disease↗
PubMedDate not supplied

Chromosome abnormalities in human embryos.

The presence of numerical chromosome abnormalities in human embryos was studied using fluorescence in-situ hybridization with four or more chromosome-specific probes. When most cells of an embryo are analysed, this technique allows differentiation to be made between aneuploidy, mosaicism, haploidy and polyploidy. Abnormal types of fertilization, such as unipronucleated, tripronucleated zygotes and zygotes with uneven pronuclei, were studied using this technique. We have found a strong correlation between some types of dysmorphism with chromosomal abnormalities. In addition, the more impaired the development of an embryo, the more chromosomal abnormalities were detected in those embryos. Maternal age and other factors were linked to an increase in chromosome abnormalities (hormonal regimes, temperature changes), but not to intracytoplasmic sperm injection.

Aneuploidy↗
PubMed2001

Detection of structural and numerical chromosome abnormalities in interphase cells using spectral imaging.

Chromosome abnormalities are common causes of congenital malformations and spontaneous abortions. They include structural abnormalities, polyploidy, trisomy, and mosaicism. In in vitro fertilization (IVF) programs, preimplantation genetic diagnosis (PGD) of oocytes and embryos has become the technique of choice to select against abnormal embryos before embryo transfer. For diagnosis of structural abnormalities, we developed case-specific breakpoint-spanning DNA probes. Screening of an in-house yeast artificial chromosome (YAC) library is facilitated by information from publicly available databases and published articles. Most numerical chromosome abnormalities, on the other hand, are detrimental to early embryonic development and increase with maternal age. We therefore developed a multichromosome screening technique based on spectral imaging to simultaneously detect and score as many as 10 different chromosome types. The probe set was chosen to detect more than 70% of all numerical chromosome aberrations responsible for spontaneous abortions. Detecting structural and numerical abnormalities in single interphase cells using spectral imaging is a powerful technique for multilocus genetic screening.

Chromosome Aberrations↗
PubMed2006

[Rapid prenatal diagnosis of chromosomal abnormalities; limitations and possibilities].

In the past, prenatal diagnosis of chromosomal abnormalities has been achieved using a microscope to make a visual assessment of the chromosomes in foetal cells which had been obtained by invasive procedures. The results were usually not available until 10-14 days later. Now molecular techniques have become available which provide a result within 24-48 hours. The first generation of these techniques combines speed with a focus on a limited number of frequent and important chromosomal abnormalities. Examples include fluorescence in-situ hybridisation (FISH), quantitative polymerase chain reaction (PCR) and multiple ligation-dependent probe amplification (MLPA). One drawback, therefore, is that other clinically significant chromosomal abnormalities will not be detected. More recently other new techniques have been making their appearance, such as array-comparative genomic hybridisation (CGH), which will allow the detection of clinically significant submicroscopic aberrations.

Chromosome Aberrations↗
PubMed1997

Chromosome abnormalities of the short arm of chromosome 12 in hematopoietic malignancies: a report including three novel translocations involving the TEL/ETV6 gene.

A wide variety of abnormalities of the short arm of chromosome 12 has been reported in hematologic malignancies. The most frequent rearrangements result from t(12;21)(p13;q22) of childhood acute lymphoblastic leukemia, a translocation cryptic when leukemic cells are analyzed with chromosome banding techniques. This translocation results in a fusion of the TEL/ETV6 and AML1 genes. In this report, examples of rearrangements of 12p are presented. Study of two complex chromosome abnormalities associated with t(12;21) emphasizes the importance of using FISH in detection of such translocations. Three novel translocations involving the TEL/ETV6 gene localized on 12p13 are also reported: t(X;12)(q28;p13), t(1;12)(q21;p13), and t(9;12)(p23-24;p13). Finally, the presentation of two translocations with breakpoints located centromeric to TEL/ETV6 highlights the not uncommon involvement of genes other than TEL/ETV6 on 12p.

Adolescent↗
PubMed2002

[CD5+ CD10+ extranodal B-cell lymphoma with tetraploid chromosomal abnormality].

An 84-year-old man was admitted with pleural lymphomatous effusion and bone marrow infiltration. The abnormal cells from the effusion showed abundant basophilic cytoplasm, large atypical nuclei, and small nucleoli with frequent mitosis. The abnormal cells were found to be CD5+, CD10+, CD19+, and CD20+ by flow cytometry, and had clonal rearrangements of the IgH-JH gene, indicating the existence of a clonal B-cell population. No bcl-1, bcl-2, bcl-6, or c-myc rearrangement was found. Neither human herpesvirus 8 (HHV-8) nor Epstein-Barr virus was detected in the abnormal cells. Tetraploid chromosomal abnormality was present. After administration of prednisolone, transient disappearance of the effusion was obtained.

Aged↗
PubMed1985

Chromosomal abnormalities in human sperm.

The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhaps reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.

Aneuploidy↗
PubMed1987

Chromosome abnormalities in AIDS-associated lymphadenopathy.

Cytogenetic studies were performed on direct and 24-hour culture preparations of eight lymph node biopsies from seven patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC)-associated lymphadenopathy in whom histological evidence of lymphoma was not detected. Three of these seven had chromosomal abnormalities, including chromosome instability in one and clonal chromosomal abnormalities in two; one of the latter was a t(8;14)(q24;q32). The remaining five showed normal karyotypes. Epstein-Barr virus (EBV) titers were elevated in all three patients that exhibited chromosome abnormalities, two of whom later developed malignant lymphoma. A control group of five patients with reactive lymphadenopathy not associated with AIDS failed to reveal chromosomal aberrations, but elevated EBV titers were present in two. These data are consistent with current views on the role of EBV and chromosome change in the development of lymphoma in immunodeficient states and suggest that karyotypically abnormal AIDS-related lymphadenopathy represents a prelymphomatous proliferation.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Relationship between an activated N-ras oncogene and chromosomal abnormality during leukemic progression from myelodysplastic syndrome.

The relationship between chromosomal abnormality and oncogene activation was investigated during leukemic progression in two patients with myelodysplastic syndrome (MDS). Both patients had partial or complete deletion of chromosome 5 in metaphase cells obtained throughout the progression to leukemia. Analysis with specific oligonucleotide probes revealed that bone marrow cells containing an activated N-ras oncogene proliferated in a dominant manner during the process of leukemic conversion in both patients. These observations suggest that the chromosomal abnormality may precede activation of the N-ras gene in these patients, and that both the chromosomal abnormality and the activated N-ras oncogene contribute to the development of leukemia.

Acute Disease↗
PubMed2006

Screening for chromosomal abnormalities in 2650 infertile couples undergoing ICSI.

Chromosomal abnormalities are the major contributor to the genetic risks of infertility treatment associated with intracytoplasmic sperm injection (ICSI). The study objective was to assess prospectively the frequency of chromosomal aberrations in couples undergoing ICSI. A total of 2650 infertile couples (5300 patients) underwent chromosome analysis before undergoing ICSI in the Egyptian IVF-ET Centre. Heparinized blood samples were cultured, harvested and banded according to standard methods. Overall, 96.94% of the patients studied (5138/5300) had a normal karyotype, while the remaining 162 patients (3.06%) had an abnormal karyotype. Male patients constituted the majority of abnormalities; 138 males (85.19%) and 24 females (14.81%). These chromosomal aberrations included 117 cases (2.2%) of sex chromosome abnormalities; 113 males and four females. Forty-five patients (0.85%) had autosomal aberrations; 25 of them were males and 20 were females. The current data show that chromosomal abnormalities affect 3.06% of infertile patients, and occur in both sexes, but more predominantly in males undergoing ICSI for male factor infertility. It is recommended that chromosomal analysis be performed before undergoing ICSI, to identify patients who can be offered preimplantation genetic diagnosis.

Chromosome Aberrations↗
PubMedDate not supplied

Chromosomal abnormalities in 457 Turkish patients with MCA/MR.

The evaluation of multiple congenital abnormalities and/or mental retardation (MCA/MR) is always a challenge to clinicians. The recognition of specific physical or behavioral characteristics can vastly improve diagnostic yield. Chromosomal abnormalities account for a high percentage in the etiology of MCA/MR. In this study, frequency of chromosomal abnormalities was 4.81% of 457 patients. Chromosomal abnormalities and polymorphisms were detected in 65 (14.21%) (structural and numerical chromosomal abnormalities in 22 patients and polymorphisms in 43) of 457 MR and/or MCA patients. Our results show that chromosomal abnormalities contribute much to the causation of multiple malformations and/or MR. It is essential that fluorescence in situ hybridization (FISH) be used in conjunction with standard methods in order to maximize obtainable information for better management of patients with MR and/or MCA.

Abnormalities, Multiple↗
PubMed1999

Frequencies of chromosomal abnormalities at amniocentesis: over 20 years of cytogenetic analyses in one laboratory.

Prenatal diagnosis of chromosomal disorders has been performed for more than 20 years, mainly for advanced maternal age. Chromosomal abnormality rates derived from second trimester amniocentesis have mainly come from a collection of small-scale studies from North America and Western Europe. Accurate risk estimates for chromosomal abnormalities are important tools for the physician or obstetrician who would need to make referrals to a prenatal genetic center. This paper presents amniocentesis rates of clinically significant cytogenetic abnormalities for various indications, including advanced maternal age, previous chromosomal abnormality, parental structural rearrangement and a family history of aneuploidy as defined in the text. These data come from a Canadian prenatal diagnosis laboratory with more than 20 years experience in second trimester cytogenetic analysis. They show that the overall frequency of chromosomal abnormalities for advanced maternal age (> or = 35 years) is 1.79%. In this group, 21% of all abnormalities are structural rearrangements (including markers) and less than half of all abnormalities are trisomy 21. The advanced maternal age specific risk of aneuploidies at second trimester is 1.24%. Recurrence risk for aneuploidy after a previous one is 1.29%. However, it is much higher (4.84%) for women of > or = 35 years. When a parent's brother, sister, nephew or niece is affected, the risk of occurrence of aneuploidies (0.24%) is not elevated. When there is a balanced translocation in one of the parents, the overall risk is 10.2% for unbalanced translocations and 37.3% for balanced translocations.

Amniocentesis↗
PubMed1990

The role of chromosome abnormalities in reproductive failure.

The frequency of chromosome abnormalities in spontaneous abortions, stillbirths, livebirths and among all clinically recognized pregnancies is given. Data on the parental origin of sex chromosome abnormalities and certain autosomal trisomies determined using molecular probes are presented and the proportion of sperm and eggs that are nullisomic or disomic for a sex chromosome to an autosome 16, 18 or 21 is calculated.

Abortion, Spontaneous↗
PubMed1985

Chromosome abnormalities, sister chromatid exchanges, and cell cycle analysis in phytohemagglutinin-stimulated adult T cell leukemia lymphocytes.

Chromosome abnormalities, sister chromatid exchanges (SCE), and cell cycle kinetics were studied in phytohemagglutinin-stimulated lymphocytes from 8 adult T cell leukemia (ATL) patients. In all these cases, chromosome abnormalities were observed in 5-day PHA-stimulated cultures. Four cases had characteristic marker chromosomes; two were due to a balanced translocation, t(9;21), and two to a simple deletion, 5p-. The other four cases, however, had rather complicated chromosome abnormalities, e.g., 1q+, 2q+, 5q+, 6q-, 14q+, 10p-. When chromosome abnormalities were analyzed in previously reported cases, the abnormalities were mostly distributed among chromosomes #1, #2, #5, #6, #14, and #21. These findings suggest that the abnormalities involving #1, #2, #5, #6, #14, and #21 are intimately related to ATL. The SCE frequency was in the normal range in ATL cells. Cell cycle analysis revealed that the duration of two cell cycles in cells labeled with bromodeoxyuridine (BrdU) required approximately 80 hr in ATL cells, whereas the time of two cell cycles in normal cells is 40 hr. These findings indicate that the ATL cell cycle time is about 40 hr, about double that of normal cells (20 hr), in PHA-stimulated cultures. ATL has been known to be a mature T cell leukemia and to respond poorly to chemotherapy. The latter may be due to the elongated cell cycle or to the mature characteristics of the leukemic cells. The association of ATL with cutaneous T cell lymphoma is also discussed.

Adult↗
PubMed1995

dic(9;20): a new recurrent chromosome abnormality in adult acute lymphoblastic leukemia.

Loss of chromosome 20 and rearrangement of the short arm of chromosome 9 were identified by banding analysis of three adult patients with acute lymphoblastic leukemia (ALL). The G-banding pattern suggested an identical deletion of 9p, but, also, an unbalanced translocation with chromosome 20 was taken into consideration. Dual-color chromosome painting with probes for chromosomes 9 and 20 revealed the presence of material from chromosome 20 at the short arm of the abnormal chromosome 9 in all three cases. Centromeric alpha-satellite DNA of both chromosome 9 and chromosome 20 was demonstrated by fluorescence in situ hybridization and indicated the presence of a dicentric chromosome. The hybridization of a YAC clone of the short arm of chromosome 20 proved that the dicentric chromosome contained the short arm of chromosome 20, which had been suspected from the G-banding pattern. Thus, the rearrangement was interpreted as dic(9;20)(p11;q11.?1). Because this was the sole chromosome abnormality in two patients, dic(9;20) may be a primary chromosome aberration in ALL. In one case, a 9q+ chromosome derived from a Philadelphia (Ph) translocation was involved in the formation of the dicentric chromosome. Immunophenotyping revealed CD10+ B-cell precursor ALL in all three cases. Whereas the two patients in whom dic(9;20) was the sole cytogenetically detectable change are in continuous complete remission for 10 and 45 months, respectively, the Ph+ patient relapsed with leukemia and died 8 months after diagnosis.

Adult↗
PubMedDate not supplied

The frequency of chromosomal abnormalities in patients referred for fragile X analysis.

The present paper summarizes our existing database on chromosomal abnormalities found in patients referred because of a question of the Fragile X Syndrome during the period from January 1, 1990 to June 30, 1995. Cytogenetic results were derived from testing performed at the cytogenetics laboratory at Rhode Island Hospital. All positive fragile X individuals detected among our sample population represent index patients from separate kindreds. Of a total of 327 cases referred for fragile X testing, 10 (3.06 percent) were found to be positive for fragile X by either cytogenetics alone or by both cytogenetics and DNA testing, 12 (3.60 percent) were found to be positive for either a numerical or structural chromosomal abnormality, while 10 (3.06 percent) were found to exhibit a heteromorphism. Positive chromosomal findings included numerical chromosomal abnormalities of the sex chromosomes and autosomes, deletions, and translocations. Heteromorphism mostly involved an increase in the length of heterochromatic regions of certain chromosomes as well as a pericentric inversion of a chromosome 9, usually considered normal variants. It is concluded that chromosomal abnormalities other than fragile X are found with equal and, in some cases, higher frequency than the frequency of fragile X positivity in patients referred for a question of the Fragile X Syndrome. Our figures, consistent with those reported in the literature, underscore the value of routine karyotyping in this population of patients. Except under special circumstances, it is important that GTG-banding analysis be performed so that the entire human genome be examined in addition to scoring for the fragile X mutation on Xq27.3. Especially in view of the recent finding of the relative rarity of this condition, the exclusive use of DNA analysis is not advised.

Chromosome Aberrations↗