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PubMedDate not supplied

Elevated second-trimester maternal urine free beta-human chorionic gonadotropin levels in Asian pregnancies with fetal chromosomal abnormalities.

OBJECTIVES: To investigate the second trimester maternal urine free beta-human chorionic gonadotropin (hCG) levels of chromosomally abnormal pregnancies in Asians. METHODS: Free beta-hCG levels were analyzed from the urine samples of 110 control and 17 chromosomally abnormal pregnancies, including 11 cases of Down syndrome, 1 case of trisomy 18, and other chromosomal abnormalities (one mosaic deletion and 4 translocations) from the second trimester of pregnancy. Results were normalized to urine creatinine (Cr) concentration and converted to the multiple of the median (MOM) level for the appropriate gestation. Gestational age of all cases was determined by ultrasound parameters. RESULTS: The median free beta-hCG MOM levels of Down syndrome (4.02 MOM) and other chromosomally abnormal pregnancies (2.03 MOM) are significantly higher than that of normal pregnancies (0.99 MOM) (p = 0.002 and p = 0.024, respectively). Nine of 11 (81.8%) Down syndrome cases, one trisomy 18 case, and 2 of 5 (40%) other chromosomally abnormal cases would be expected to be above the 95th centile of the control values (2.95 MOM cut-off). CONCLUSION: Urine free beta-hCG could be a potential and useful marker in the detection of fetal Down syndrome and other chromosomal abnormalities in Asians.

Adult↗

PubMed2003

Chromosomal abnormalities and embryo development in recurrent miscarriage couples.

BACKGROUND: Chromosomal abnormalities are an important cause of spontaneous abortion and recurrent miscarriage (RM). Therefore, we have analysed the incidence of chromosomal abnormalities and embryo development in patients with RM. METHODS: Preimplantation genetic diagnosis (PGD) was performed on 71 couples with RM and 28 couples undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in-situ hybridization. RESULTS: The implantation rate in RM patients was 28% and three patients (13%) miscarried. The percentage of abnormal embryos was significantly increased (P < 0.0001) in RM patients compared with controls (70.7 versus 45.1%). All of the embryos were abnormal in 19 cycles (22.1%) and repeated PGD cycles yielded similar rates of chromosomal abnormalities in 14 couples. Anomalies for chromosomes 16 and 22 were significantly higher (P < 0.01) in RM cases. In the RM population, euploid embryos reached the blastocyst stage more frequently than abnormal embryos (61.7 versus 24.9%; P < 0.0001). CONCLUSIONS: RM is associated with a higher incidence of chromosomally abnormal embryos, of which some are able to develop to the blastocyst stage. IVF plus PGD is an important step in the management of these couples, but the technique has to move towards a full chromosome analysis.

Abortion, Habitual↗

PubMed2001

Obstetric ultrasonographic findings and fetal chromosomal abnormalities: refining the association.

OBJECTIVE: In an attempt to refine the role of ultrasonography in screening and identifying fetuses at risk for chromosomal abnormalities, a retrospective review of patients undergoing genetic amniocentesis was undertaken. STUDY DESIGN: Computer databases from the perinatal biology laboratory and cytogenetics laboratory of our institution were correlated to compare the results of the fetus' ultrasonographic examination with the cytogenetic results from amniocentesis. Univariate and multivariate analysis were used to determine the best correlations between ultrasonographic findings and chromosomal abnormalities (study 1). The results were used to construct regression analysis formulas and a Neural Network program to predict the presence or absence of chromosomal abnormalities in a second set of patients (study 2) undergoing genetic amniocentesis. RESULTS: One hundred twenty-five chromosomal abnormalities were found in 3775 fetuses in study 1 (3.3%). Multivariate analysis showed significant correlations between anomalies of the central nervous system, heart, face and neck, and extremities and increased nuchal fold, increased bowel echogenicity, abnormal biparietal diameter-to-femur ratio, and the presence of chromosomal abnormalities. Regression equations and a Neural Network program successfully predicted the presence or absence of fetal chromosomal abnormalities in a second set of 901 at-risk fetuses. CONCLUSION: A normal ultrasonographic examination result in patients who are at increased risk for fetal chromosomal abnormalities reduces the risk 2- to 3-fold, whereas the presence of any major ultrasonographic abnormality or certain minor abnormalities significantly increases the risk. The application of these results to low-risk patients is still premature.

Adolescent↗

PubMed1995

Spontaneous and ionizing radiation-induced chromosomal abnormalities in p53-deficient mice.

Chromosomal abnormalities have been assessed in p53-deficient mice. The in vivo frequency of spontaneous stable aberrations in bone marrow cells was elevated by approximately 20-fold in p53 nulls and 13-fold in p53 heterozygotes compared to wild-type. No excessive induction of stable aberrations by gamma-irradiation was observed, but p53 deficiency resulted in excess radiation-induced hyperploidy (> 10-fold wild-type frequency). No influence of p53 genotype on sister chromatid exchange or G2 chromatid damage was observed in mitogen-stimulated spleen cell cultures; however, a p53 effect on postirradiation mitotic entry was seen. Abnormalities in chromosome segregation and mitotic delay following irradiation in p53-deficient mice suggest a G2-M checkpoint role for p53 and are broadly consistent with data on tumorigenesis in these animals.

Aneuploidy↗

PubMed2003

A comparison of the frequency of sperm chromosome abnormalities in men with mild, moderate, and severe oligozoospermia.

Infertile men undergoing intracytoplasmic sperm injection have an increased frequency of chromosome abnormalities in their sperm. Men with low sperm concentration (oligozoospermia) have an increased risk of sperm chromosome abnormalities. This study was initiated to determine whether men with severe oligozoospermia (<10(6) sperm/ml) have a higher frequency of chromosome abnormalities in their sperm compared with men with moderate (1-9 x 10(6) sperm/ml) or mild (10-19 x 10(6) sperm/ml) oligozoospermia. Multicolor fluorescence in situ hybridization analysis was performed using DNA probes specific for chromosomes 13, 21, X, and Y (with chromosome 1 as an autosomal control for the sex chromosomes). Aneuploidy and disomy frequencies were assessed from a total of 603,011 sperm from 30 men: 10 in each of the categories. The mean frequencies of disomy for the patients with mild, moderate, and severe oligozoospermia were 0.17%, 0.24%, and 0.30%, respectively, for chromosome 13 and 0.22%, 0.44%, and 0.58%, respectively, for chromosome 21. For the sex chromosomes, the mean frequencies of disomy for mild, moderate, and severe oligozoospermia were 0.25%, 1.04%, and 0.68%, respectively, for XY, 0.047%, 0.08%, and 0.10%, respectively, for XX, and 0.04%, 0.06%, and 0.09%, respectively, for YY. The frequencies for diploidy also increased from 0.4% for mild to 1.20% for moderate to 1.24% for severe oligozoospermia. There was a significant inverse correlation between the frequency of sperm chromosome abnormalities and the sperm concentration for XY, XX, and YY disomy and diploidy. These results demonstrate that men with severe oligozoospermia have an elevated risk for chromosome abnormalities in their sperm, particularly sex chromosome abnormalities.

Adult↗

PubMed1995

Prenatal diagnosis of diverse chromosome abnormalities in a population of patients identified by triple-marker testing as screen positive for Down syndrome.

OBJECTIVE: Our purpose was to determine the incidence of all types of chromosome abnormalities (i.e., trisomy 21 and other abnormalities) in women receiving prenatal chromosome analysis after a Down syndrome screen-positive result by maternal serum triple-marker testing (alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol analyses). STUDY DESIGN: A total of 11,434 patients between 15.0 and 21.9 weeks' gestation received second-trimester Down syndrome risk evaluation by triple-marker testing. By use of a 1:270 midtrimester Down syndrome risk cutoff value, and after ultrasonographic confirmation of gestational age, 677 patients were screen positive for Down syndrome (corrected screen-positive rate 5.92%). Karyotypes were reviewed for 468 (69%) of these patients who received prenatal chromosome analysis. RESULTS: In addition to 12 cases of Down syndrome, 12 other fetal chromosome abnormalities were found (i.e., 5.13% had a chromosome abnormality of some type). Expressed as a proportion of all patients with a corrected Down syndrome screen-positive result, at least 3.69% had a chromosome abnormality. The overall spectrum of abnormal karyotypes (approximately 50% autosomal trisomy, 25% structural and 25% sex chromosome abnormality) appears to be comparable to that seen in patients undergoing amniocentesis because of advanced maternal age. CONCLUSIONS: As is the case for women of advanced maternal age, preamniocentesis counseling for patients with positive triple-marker testing results should reflect the relatively high probability that an abnormality other than Down syndrome may be identified.

Adult↗

PubMed1994

Chromosome abnormalities in meningeal neoplasms: do they correlate with histology?

Thirty-three meningeal neoplasms were karyotyped, and the results were compared with histologic features. Thirteen neoplasms had no discernible abnormality or sex chromosome loss only; nine had monosomy or structural abnormality involving only chromosome 22; and 11 had other chromosome abnormalities with or without chromosome 22 involvement. Histologic evidence of invasion was not associated with an abnormal karyotype in the three angioblastic tumors examined. All seven fibroblastic meningiomas had abnormal karyotypes, with monosomy 22 the most common change. Abnormal karyotypes were detected in 76% of syncytial and 55% of transitional meningiomas. When these results were combined with those from 259 meningeal tumors reported since 1987, abnormal karyotypes were detected in at least half of all histologic types. Chromosome changes secondary to those involving chromosome 22 may indicate additional areas of the genome that play a role in tumor progression. In the combined series, chromosome losses were most frequently observed in meningiomatous and transitional histologies; chromosomes 1, 6, 14, 18, and Y each were lost in 10 or more meningiomas, whereas only chromosome 20 was gained at the same frequency. Structural abnormalities most frequently involved chromosome 1. These changes are distinctly different from those observed in other common intracranial neoplasms, specifically astrocytic neoplasms.

Adult↗

PubMed2002

Cytogenetic evaluation of isochromosome 17q in posterior fossa tumors of children and correlation with clinical outcome in medulloblastoma. Detection of a novel chromosomal abnormality.

BACKGROUND: A number of chromosomal abnormalities have been described in the presence of central nervous system tumors; isochromosome 17q, representing a loss of heterozygosity for the short arm of the chromosome 17, is the one most frequently reported in association with medulloblastoma. The purpose of this study was to evaluate the prognostic correlation of this variable, compared with other variables (surgery extent and radiotherapy), with survival. METHODS AND RESULTS: We looked for the presence of i(17q) in 32 children affected by posterior fossa tumors, including 16 medulloblastomas and 2 teratoid/rhabdoid tumors. For our study we used both karyotypic analysis and the fluorescence in situ hybridization (FISH) procedure, both on fresh and on paraffin-embedded tissues. Cytogenetic analysis allowed us to detect a hitherto unreported abnormality in medulloblastoma: ins(1;10)(q31;q23q26). Moreover, 16 of the 32 patients analyzed by FISH were found to be positive for the presence of i(17q): the 2 with teratoid/rhabdoid tumors, 11 of 16 with medulloblastomas, plus 1 with ependymoblastoma and 2 with anaplastic astrocytomas. As far as the outcome of medulloblastoma patients is concerned, we found that 8 out of the 10 children whose tumor had been totally removed had a favorable outcome regardless of the presence of i(17q): 4 were i(17q) positive and 4 i(17q) negative. CONCLUSIONS: Although it was impossible to draw any definitive conclusion about detection of i(17q) in central nervous system tumors in infancy, particularly in the case of medulloblastoma, we suggest that this chromosomal abnormality is not an independent prognostic factor, but may be a marker for uncontrolled cell proliferation.

Cerebellar Neoplasms↗

PubMed1993

The origin of cytologically unidentifiable chromosome abnormalities: six cases ascertained by targeted chromosome-band painting.

De novo chromosome structural abnormalities cannot always be diagnosed by the use of standard cytogenetic techniques. We applied a previously developed chromosome-band-specific painting method to the diagnosis of such rearrangements. The diagnostic procedures consisted of microdissection of an aberrant chromosomal region of a given patient, polymerase chain reaction (PCR) amplification of the dissected chromosomal DNA, and subsequent competitive fluorescence in situ hybridization (FISH) using the PCR products as a probe pool on metaphase chromosomes from the patient and/or a karyotypically normal person. With this strategy, we studied 6 de novo rearrangements (6p+, 6q+, 9p+, 17p+, +mar, and +mar) in 6 patients. These rearrangements had been seen by conventional banding but their origin could not be identified. In all 6 patients, we successfully ascertained the origin. Using an aberrant region-specific probe pool, FISH signals appeared on both the aberrant region and a region of another specific chromosome pair. A reverse probe pool that was generated through the microdissection of normal chromosomes at a candidate region for the origin of the aberration hybridized with both the aberrant and the candidate regions. We thus diagnosed one patient with 17p+ as having trisomy for 14q32-qter, one with 9p+ as having trisomy for 12pter-p12, one with 6q+ as having a tandem duplication (trisomy) of a 6q23-q25 segment, one with 6p+ as having a tandem duplication (trisomy) of a 6p23-q21.3 segment, one with a supernumerary metacentric marker chromosome as having tetrasomy for 18pter-cen, and the last with an additional small marker chromosome as having trisomy for 18p11.1 (or p11.2)-q11.2. The present targeted chromosome-band-painting method provides the simple and rapid preparation of a probe pool for region-specific FISH, and is useful for the diagnosis of chromosome abnormalities of unknown origin.

Base Sequence↗

PubMed2004

[Phenotypic consequences of chromosome abnormalities].

The incidence of chromosome anomalies in newborn infants is 0.7-0.8 %. The phenotypic manifestations of chromosomal abnormalities are highly diverse. These anomalies may be present in phenotypically normal individuals in whom they can increase the risk of recurrent miscarriage and birth defects and/or mental retardation. It is important to determine this risk to provide patients with appropriate genetic counseling.

Chromosome Disorders↗

PubMed2006

De novo chromosomal abnormalities and month of conception.

OBJECTIVES: We set out to study the possible relationship between the occurrence of chromosomal abnormalities and the month of conception using data from 7 years of prenatal diagnosis. METHODS: The sample included 7439 cytogenetic analyses from amniocentesis performed for conceptions between 1997 and 2003. The monthly prevalence of all de novo chromosomal abnormalities, trisomies, including trisomy 21, and Robertsonian translocations was investigated. RESULTS: Two hundred and four de novo numerical and structural chromosomal abnormalities (2.7%) were detected. A significant decrease in the frequencies of all de novo chromosomal abnormalities for June conceptions, as well as lower summer occurrences of trisomy 21, were found. In addition, de novo Robertsonian translocations were unexpectedly detected only among December conceptions. CONCLUSIONS: The relationship between chromosomal abnormalities and the month of conception could turn out to be useful in estimating the actual risk in pregnancy, if confirmed by other studies. The observed June lowest rate might indicate an association between chromosomal abnormalities and the maximum number of daylight hours throughout the year (summer solstice). We cannot explain the unusual findings concerning Robertsonian translocations that were only found for conceptions in December. This may be related to the annual minimum daylight hours (winter solstice) as opposed to the summer solstice.

Amniocentesis↗

PubMed1981

Dermatoglyphics in medicine--problems and use in suspected chromosome abnormalities.

Dermatoglyphic findings in patients with chromosome abnormalities are reviewed including the more common aneuploidies and recently recognized deficiency and duplication syndromes. Tables of dermatoglyphic changes are provided to help in the diagnosis of patients with suspected chromosome abnormalities. Finally, problems of dermatoglyphic nomenclature and statistics are considered. It is emphasized that dermatoglyphics should be used in conjunction with the physical examination rather than as an independent diagnostic test.

Child↗

PubMed1985

[Male infertility with chromosomal abnormalities. I. XYY syndrome].

Chromosomal abnormalities are found in a considerably high percentage of cases of male infertility, in particular azoospermia. We report a case of the XYY syndrome and review the literature. A 36-year-old man, a factory hand, presented with infertility. He was safely delivered at term as a fourth child when his father was 41 years old and his mother 38. He had no delinquent or criminal record. His height was 179 cm, weight 75 kg and distance of extended hands 184 cm. No gynecomastia was noticed. Both testes were 8ml in size and growth of pubic hair and penis were normal. Severe oligozoospermia was identified in semen analysis. Seminal vesiculography showed pathological dilatation of the seminal vas end. The testicular biopsy specimens revealed spermatogenic arrest for the most part. Chromosomal analysis showed 47, XYY karyotype; and, two Y-chromatin was revealed in cultured lymphocytes. Though plasma gonadotropin levels were high, testosterone, estradiol, prolactin, TSH, GH, T3 and T4 levels were within normal limits. Pituitary reserve function for secreting gonadotropins and Leydig cell reserve function to secrete testosterone have been found to be almost normal.

Adult↗

PubMed1976

Contraceptives and the conceptus. I. Chromosome abnormalities of the fetus and neonate related to maternal contraceptive history.

The chromosomes of 3080 products of conception, consisting primarily of newborn infants and medically induced abortions, were examined. These were from 3 major groups of women, those who had used oral contraceptives (primarily the combination types), those who had used nonhormonal contraceptives, and a control group of those who had not used any contraceptives. In the newborn study population, the chromosome abnormality rate was 5.4 per 1000 infants (when cases of proven hereditary involvement are excluded the figure drops to 3.6 per 1000), and in the entire induced-abortion study series it was 7.3 per 1000. These rates are very similar to those obtained in other surveys. The rate of chromosomally abnormal conceptuses increases with increasing maternal age in both the newborn and induced-abortion groups. No statistically significant relationships were found between the observed or age-adjusted rates of chromosome abnormalities and contraceptive history (P greater than .10 in all cases). The findings make it clear that the use of oral contraceptives has no large effect on the risk of having a chromosomally abnormal child although the possibility of a small increase or decrease in this risk, of at most about 10 per 1000, cannot be ruled out because of the small number of abnormalities found.

Abnormalities, Drug-Induced↗

PubMed2002

Fifty-one prenatally diagnosed children and adolescents with sex chromosome abnormalities.

Children with sex chromosome abnormalities (SCA) are known to be at risk for developmental delays. These risks were identified 2 decades ago by seven international research groups who prospectively followed children ascertained after birth. Subsequently, some of these investigators suggested the course of prenatally identified children with SCA may be different from children in earlier studies. The first such evidence was published by Robinson et al. [1992: Am J Med Genet 44:365-368], who compared 20 prenatally diagnosed children to the original postnatally diagnosed cohort. The following report presents an update and expansion of that research and includes 51 children and adolescents prenatally diagnosed with SCA, now 7-18 years of age. Results confirm that this cohort of prenatally diagnosed children has a milder developmental course than children ascertained postnatally. The study provides new information to health professionals counseling families faced with prenatal diagnosis of SCA.

Adolescent↗

PubMed1987

Retinoblastoma, chromosome abnormalities and oncogene expression.

Recurrent chromosomal abnormalities in retinoblastomas involve numbers 13, 1, and 6, as well as homogeneously staining regions (HSR) and double minutes (DMS). Evidence suggesting that chromosome 13 contains a gene responsible for tumorigenesis has already been presented. We postulate that the genetic changes resulting from abnormalities of chromosomes 1 and 6 and the HSR/DMS provide a selective growth advantage to cells in which they occur. Support for this hypothesis, as it relates to the HSR/DMS and oncogene amplification, is discussed.

Chromosome Aberrations↗

PubMed2006

Additional chromosomal abnormalities in patients with a previously detected abnormal karyotype, mental retardation, and dysmorphic features.

The detection of chromosomal abnormalities in patients with mental retardation (MR) and dysmorphic features increases with improvements of molecular cytogenetic methods. We report on six patients referred for detailed characterization of chromosomal abnormalities (four translocations, one inversion, one deletion) detected by conventional cytogenetics, in whom metaphase CGH revealed imbalances not involved in the initially detected rearrangements. The detected abnormalities were validated by real-time PCR. Parents were investigated by CGH in four cases. The genomic screening revealed interstitial deletions of 2q33.2-q34, 3p21, 4q12-q13.1, 6q25, 13q22.2-q31.1, and 14q12. The estimated minimum sizes of the deletions ranged from 2.65 to 9.27 Mb. The CGH assay did not reveal imbalances that colocalized with the breakpoints of the inversion or the translocations. The deletion of 6q included ESR1, in which polymorphisms are associated with variation of adult height. FOXG1B, known to be involved in cortical development, was located in the 14q deletion. The results illustrate that whole-genome molecular cytogenetic analysis of phenotypically affected patients with abnormal conventional karyotypes may detect inapparent molecular cytogenetic abnormalities in patients with microscopic chromosomal abnormalities and that these data provide additional information of clinical importance.

Adolescent↗

PubMed1994

Flow cytometric detection of chromosome abnormalities by measuring centromeric index, DNA content, and DNA base composition.

This paper highlights two improvements of the on-line centromeric index (CI) analysis for the detection of chromosome abnormalities. On-line CI versus DNA content analysis of an EBV-transformed cell line, with a deletion (11)(p13p15.1), of a patient with aniridia and Wilms' tumour demonstrates the first improvement of the method of on-line CI analysis for flow karyotyping and sorting; a reciprocal translocation, insertion, or deletion can, when the cell type contains not more than a few of these types of abnormalities, be traced to the p-arm or q-arm of the relevant chromosome. On-line CI analysis was also performed with chromosomes isolated from a transitional cell carcinoma of the bladder. Cytogenetic analysis of this cell line showed numerous chromosomal abnormalities. Chromosomes of this cell line were also karyotyped by bivariate flow cytometry using a different set of parameters: Hoechst 33,258 fluorescence intensity (HOfl) versus chromomycin A3 fluorescence intensity (CAfl). A comparison of these results reveals the second improvement of the CI method for the detection of chromosome abnormalities; bivariate analysis of CI versus propidium fluorescence (PIfl) are complementary to bivariate analysis of HOfl versus CAfl. Chromosomes with distributions that fuse together in the HO/CA flow karyotype may be distinguished as individual peaks on the basis of their CI values.

Aniridia↗