Chromosomal abnormalities

FISH. Fluorescent in-situ hybridization a method utilizing fluorescently labeled DNA probes to detect or confirm gene or chromosome abnormalities that are generally beyond the resolution of routine cytogenetics. 

Is to determine the sex of the fetus the other Is to determine whether the fetus has a chromosome abnormality Fetal sex determination Is not, at present, performed so that couples can chose the sex of their baby While there may not be any significant ethical or sociological (43) reasons to oppose sex determination for this reason, the lack of sufficient facilities has made this an Indication of extremely low priority The reason for ascertaining the sex of a fetus. In so far as the prenatal diagnosis of genetic disease Is concerned. Is to determine Aether the fetus Is a male or female In situations In which the parents are at risk of having a child with an X-llnked disorder which affects only males If the fetus Is a male. It will have a 50% risk of being affected This risk. In such... 

The sex chromosome abnormalities are generally less severe In terms of their effects on mental development, but two of them, the XO and XX abnormalities, are associated with sterility and other abnormalities In Individuals who develop as females or males, respectively The two other sex chromosome abnormalities, XXX and X Y, are more problematic The XXX constitution does not produce significant abnormalities In the females who have It but can. In some Individuals, be associated with a modest degree of mental slowness (45) The XYY constitution. In the males who have It, appears to be associated with Increased stature and, at least In some Individuals, with a tendency toward antisocial behavior (46, 47) While the absolute Incidence of such behavior of XYY Individuals Is probably quite low. It Is still thou t to be higher than In a chromosomally normal population These two sex-chromosome abnormalities have been specifically mentioned because they have engendered considerable concern about what types of counseling should be given In situations In which they are detected prenatally ... 

While all chromosomal abnormalities can In principle be detected by prenatal diagnosis, fetal karyotyping Is not at present being done as a general screening procedure Rather,... 

It Is done under circumstances In which there appears to be a significantly Increased risk of having a child with a chromosome abnormality For the most part, this Increased risk Is associated with trisomy 21, although It can. In certain rare Instances,... 

Human Spontaneous Abortions with Chromosomal Abnormalities", Aging Gametes, Int. Symp. Seattle, (1975), 330-348. 

The influence of genetics in leukemia is supported by several observations. For example, among identical twins, the occurrence of ALL is associated with a 20% to 25% chance of the disease developing in the other twin within 1 year. In fraternal twins, there is a fourfold increase in the risk of leukemia compared with the normal population. Additionally, leukemia is known to be increased in several chromosomally abnormal populations. Patients with Down s syndrome have a 20 times increased risk of developing leukemia compared with the rest of the population. Patients with Klinefelter s syndrome and Bloom s syndrome also have an increased incidence of leukemias.7... 

The major prognostic factors in newly diagnosed AML are age, sub-type (FAB M2), and chromosome status. Older adults with AML (greater than 60 years), in comparison with younger patients with the same disease, have a dismal prognosis and represent a distinct population in terms of disease biology, treatment-related complications, and overall survival. These older patients have a higher incidence of unfavorable chromosomal abnormalities, such as aberrations of chromosomes 5,7, or 8, and fewer abnormalities that are associated with a more favorable outcome, such as t(8 21) or inv(16) (see Table 92—6).9... 

Even though chromosomal abnormalities correlate with prognosis in adult AML, they appear to have less influence on outcome. Among children, the male gender, platelet count of less than 20 x 1 03/jllL (20 x 109/L), hepatomegaly, more than 15% bone marrow blasts on day 14 of induction, myelodysplastic syndrome (MDS), and FAB sub-type M5 all were associated with lower CR rates. The absence of these features and abnormal chromosome 16 were associated with more favorable outcomes.6... 

Deknudt G, Colle A, Gerber GB. 1977. Chromosomal abnormalities in lymphocytes from monkeys poisoned with lead. Mut Res 45 7-83. 

Down s syndrome A congenital learning disorder arising from a chromosomal abnormality (trisomy 21 - an extra chromosome 21). 

Steven Rose Well I think there are a lot of problems with that claim. There was a huge statistical error made in the original presentation of that, which I think has since been widely recognised. I take it that the likely story is that this chromosomal abnormality tends to produce a lower intelligence. And people with lower intelligence tend to do less well and be more likely to end up in criminal activities. 

Neoantigens Ectopic hormones Enzyme abnormalities Increased proliferation Altered differentiation Endothelial-stimulating factors Invasion Metastasis Neoantigens Ectopic hormones Enzyme abnormalities Altered cell surface Altered cytoskeleton Chromosome abnormalities... 

Chromosome abnormalities, small changes in either number or structure. 

Fig. 5. Schematic representation of signals illustrative of chromosomal abnormalities in metaphase spreads and interphase nuclei.

Although it is possible to inherit some types of chromosomal abnormalities, most chromosomal disorders (such as Down syndrome and Turner syndrome) are not passed from one generation to the next. 

Changes in chromosome structure can also cause chromosomal disorders. Some changes in chromosome structure can be inherited, while others occur as random accidents during the formation of reproductive cells or in early fetal development. Because the inheritance of these changes can be complex, people concerned about this type of chromosomal abnormality may want to talk with a genetics professional. 

Chronic myeloid leukemia (CML) occurs when there is a translocation of chromosomes 9 and 22 (also called Philadelphia translocation—a chromosomal abnormality). These two different chromosomes break off and reattach on the opposite chromosome. A consequence is that the activity of the Bcr-Abl gene, which encodes the enzyme tyrosine kinase, is turned on all the time. With this heightened activity, high levels of white blood cells are produced in the bone marrow. 

Chromosomal abnormalities and sister chromatid exchanges have been observed in mice following intraperitoneal administration of 1,2-dibromoethane (Krishna et al. 1985). Such chromosomal aberrations were also detected in vitro using human lymphocytes (Tucker et al. 1984) however, in... 

Hayashi Y (2000) The molecular genetics of recurring chromosome abnormalities in acute myeloid leukemia [In Process Citation]. Semin Hematol 37 368-380 Heery DM, Kalkhoven E, Hoare S, Parker MG (1997) A signature motif in transcriptional co-activators mediates binding to nuclear receptors [see comments]. Nature 387 733-736 Ida K, Kitabayashi I, Taki T, Taniwaki M, Noro K, Yamamoto M, Ohki M, Hayashi Y (1997) Adenoviral E 1 A-associated protein p300 is involved in acute myeloid leukemia with t(ll 22)(q23 ql3). Blood 90 4699-4704... 

During mitosis, aU the DNA is highly condensed to allow separation of the sister chromatids. This is the only time in the ceE cycle when the chromosome structure is visible. Chromosome abnormalities may be assessed on mitotic chromosomes by karyotype analysis (metaphase chromosomes) and by banding techniques (prophase or prometaphase), which identify aneu-ploidy, translocations, deletions, inversions, and duplications. 

This chapter reviews diseases that are caused by microscopically observable alterations in chromosomes. These alterations may involve the presence of extra chromosomes or the loss of chromosomes. They may also consist of structural alterations of chromosomes. Chromosome abnormalities are seen in approximately 1 in 150 live births and are the leading known cause of mental retardation. The vast majority of chromosome abnormalities are lost prenatally chromosome abnormalities are seen in 50% of spontaneous fetal tosses during the first trimester of pregnancy, and they are seen in 20% of fetuses lost during the second trimester. Thus, chromosome abnormalities are the leading known cause of pregnancy loss. 

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