1. Cytogenetics And Chromosomal Disorders Core information about cytogenetics and chromosomal disorders is presented in the following topics. Chromosome Structure and Terminology http://arbl.cvmbs.colostate.edu/hbooks/genetics/medgen/chromo/

Genetics Index Glossary Cytogenetics and Chromosomal Disorders Cytogenetics is the study of normal and abnormal chromosomes. This includes examination of chromosome structure, learning and describing the relationships between chromosome structure and phenotype, and seeking out the causes of chromosomal abnormalities. In the simplest case, chromosomes are examined and characterized by obtaining an individual's karyotype, which is a description of the number and structure of the chromosomes. All species are affected by chromosomal disease. Its manifestations are diverse and numerous, including early embryonic death, minor to major congenital defects, development of cancer, and infertility or sterility. A broad base of knowledge is necessary in order to understand, diagnose and advise about this important class of diseases. Core information about cytogenetics and chromosomal disorders is presented in the following topics: Chromosome Structure and Terminology Preparing a Karyotype Aneuploidy and Deletions Translocations ... Overview of Chromosomal Disease Advanced and supplemental topics related to cytogenetic and chromosomeal disease are: Chromosome Numbers in Different Species Last updated on December 08, 1996

2. Chromosome Disorders Based in the UK, this nonprofit organization offers information about chromosomal disorders and a registry. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

3. Overview Of Chromosomal Disease By definition however, these children have chromosomal disorders at the Our understanding of the causes of chromosomal disorders is limited at best. http://arbl.cvmbs.colostate.edu/hbooks/genetics/medgen/chromo/chromo_dis.html

Genetics Index Glossary Overview of Chromosomal Disease Cytogenetic abnormalities are common in all species. The best data on incidence have been collected from humans, and that information seems to be very similar to what appears to be happening in other animals. Incidence and Significance Both the overall incidence, and the occurrence of specific abnormalities clearly depend upon when the data are collected relative to development. This bias is clearly understood by considering the effect on survival of minor versus major genetic lesions. For example, when newborn children are screened, it is found that roughly 1 in every 200 has a chromosomal abnormality. Some of these children are phenotypically normal, while others have obvious, sometimes severe manifestations of disease. By definition however, these children have chromosomal disorders at the "mild" end of the spectrum because they are compatible with survival to term. A much higher incidence of chromosomal disease is seen if one looks earlier in gestation. Approximately half of the human fetuses that are spontaneously aborted during the first trimester are chromosomally abnormal, reflecting chromosomal disorders severe enough to disrupt prenatal development. If one looks at chromosomes in preimplantation embryos, even higher numbers of abnormalities are seen: 5-10% of viable blastocysts collected from cattle and pigs were cytogenetically abnormal. Finally, some chromosomal abnormalities are essentially never seen, presumably because they are so profound as to cause death shortly after fertilization.

4. Chromosome Help-Station: For People With Rare Chromosome Disorders Information on rare chromosomal disorders. Support and advice for families. http://www.chromosomehelpstation.com/

(advertisements by Google) Eurochromnet Newsletter 7 - July/August 2005 Welcome to the Chromosome Help-Station! for people with rare chromosome disorders The purpose of this site is to support and advise people with rare chromosome disorders, their families and organisations. This website started April 06, 2002 by the Chromosome Help-Station Update: 28-08-2005

5. Cytogenetics And Chromosomal Disorders Cytogenetics and chromosomal disorders Cytogenetics is the study of normal and abnormal chromosomes. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

6. Can Changes In Chromosomes Cause Disorders? - Genetics Home Reference A change in the number of chromosomes leads to a chromosomal disorder. chromosomal disorders can also be caused by changes in chromosome structure. http://ghr.nlm.nih.gov/info=mutations_and_disorders/show/chromosomal_conditions

Home What's New Browse Handbook ... Search Handbook Table of Contents Chapter 2 Topics Next Topic Previous Topic Can changes in chromosomes cause disorders? Yes; changes that affect entire chromosomes or segments of chromosomes can cause problems with growth, development, and function of the body's systems. These changes can affect many genes along the chromosome and alter the proteins made by those genes. Conditions caused by a change in the number or structure of chromosomes are known as chromosomal disorders. Human cells normally contain 23 pairs of chromosomes, for a total of 46 chromosomes in each cell. A change in the number of chromosomes leads to a chromosomal disorder. These changes can occur during the formation of reproductive cells (eggs and sperm) or in early fetal development. A gain or loss of chromosomes from the normal 46 is called aneuploidy. Down syndrome chromosome 21 in each cell, for a total of 47 chromosomes per cell. Turner syndrome is a condition caused by monosomy. Women with Turner syndrome are often missing one copy of the X chromosome in every cell, for a total of 45 chromosomes per cell.

7. What Are Genetic Disorders? More about multifactorial disorders 4. Mitochondrial Disorders. These relatively rare disorders are caused by mutations in nonchromosomal DNA http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

8. Are Chromosomal Disorders Inherited? - Genetics Home Reference Are chromosomal disorders inherited? Although it is possible to inherit some types Changes in chromosome structure can also cause chromosomal disorders. http://ghr.nlm.nih.gov/info=inheritance/show/chromosomal_inheritance

Home What's New Browse Handbook ... Search Handbook Table of Contents Chapter 3 Topics Next Topic Previous Topic Are chromosomal disorders inherited? 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. Some cancer cells also have changes in the number or structure of their chromosomes. Because these changes occur in somatic cells (cells other than eggs and sperm), they cannot be passed from one generation to the next. For more information about how chromosomal changes occur: As part of its fact sheet on chromosome abnormalities, the National Human Genome Research Institute provides

9. Human Chromosomal Disorders Human chromosomal disorders February 26, 2001 Readings Web Notes Only! http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

10. THE MERCK MANUAL, Sec. 21, Ch. 286, General Principles Of Medical chromosomal disorders. Genes are carried on chromosomes; thus missing or extra chromosomes or parts of chromosomes can have a major effect on how genes in http://www.merck.com/mrkshared/mmanual/section21/chapter286/286e.jsp

11. Chromosomal Disorder Chromosomal Disorder http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

12. BBC - Health - Ask The Doctor - Coloboma So the exact genetic inheritance hasn't been identified, although it's known to be a part of certain chromosomal disorders. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

13. Human Chromosomal Disorders Human disorders due to chromosome alterations in autosomes (Chromosomes 122). There only 3 trisomies that result in a baby that can survive for a time http://www.biology.iupui.edu/biocourses/N100/2k2humancsomaldisorders.html

Human Chromosomal Disorders April 30, 2003 Readings: Web Notes Only! I. Karyotype Analysis of Human Chromosomes Karyotype preparation and analysis Cells (from blood, amniotic fluid, etc) are grown in vitro (in a cell culture dish) to increase their number Cell division is then arrested in metaphase with colchicine (prevents mitotic spindle from forming) Cells are centrifuged and lysed to release chromosomes Chromosomes are stained, photographed, and grouped by size and banding patterns This is a photograph of the 46 human chromosomes in a somatic cell, arrested in metphase. Can you see that they are duplicated sister chromatids 2. Normal male karyotype (a Cytogeneticist has lined these chromosomes up, matching homologues up and arranging them by size) 3. Normal female karyotype II. Alterations in chromosome number: Nondisjunction occurs when either homologues fail to separate during anaphase I of meiosis, or sister chromatids fail to separate during anaphase II. The result is that one gamete has 2 copies of one chromosome and the other has no copy of that chromosome. (The other chromosomes are distributed normally.) If either of these gametes unites with another during fertilization, the result is

14. Chromosomal Disorder Referral Guidelines common medical problems and birth defects associated with this specific chromosomal abnormality (e.g., thyroid disorders in patients with http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

15. Chromosomal Disorder RG common medical problems and birth defects associated with this specific chromosomal abnormality (e.g., thyroid disorders in patients with http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

16. MedlinePlus Genetic Disorders Specific Genetic Disorders (National Human Genome Research Institute) Chromosomal Abnormalities (March of Dimes Birth Defects Foundation) Also http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

17. Your Page Is Being Redirected. http://tmsyn.wc.ask.com/r?t=an&s=hb&uid=24312681243126812&sid=343126

18. Chromosome Disorders fertility.com chromosomal disorderschromosomal disorders. chromosomal disorders Infertility can arise in disorders where there is an abnormal number of sex chromosomes. http://rarediseases.about.com/health/rarediseases/cs/chromosomeproblem/

zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') zfs=0;zCMt='a70' About Rare / Orphan Diseases Information by Disease Type Chromosome Disorders Rare Diseases Essentials Rare Diseases: Basic Information Rare Diseases Support Groups ... Help zau(256,140,140,'el','http://z.about.com/0/ip/417/C.htm','');w(xb+xb+' ');zau(256,140,140,'von','http://z.about.com/0/ip/496/6.htm','');w(xb+xb); FREE Newsletter Sign Up Now for the Rare / Orphan Diseases newsletter! See Online Courses Search Rare / Orphan Diseases Chromosome Disorders Chromosomes hold the genetic keys to all of the body's functions. There may be errors on any of the body's 23 pairs of chromosomes, such as broken or missing pieces or too many pieces or copies. Links below are grouped by chromosome number (1-22 and sex chromosomes). Alphabetical Recent Up a category Wolf-Hirschhorn Syndrome (Chromosome 4) Article describes Wolf-Hirschhorn syndrome, its symptoms, diagnosis, and treatment. Cri-du-chat Syndrome (Chromosome 5) Article describes cri-du-chat syndrome, its symptoms, diagnosis, and treatment. From the About.com Guide to Rare/Orphan Diseases. Chromosome 9p Network Provides information, guest book, news, and links.

19. Sex-linked Chromosomal Disorders Sexlinked chromosomal disorders. Sex linked genetic disorders including hemophilia, color blindness, and different types of muscular dystrophy are http://www.glc.k12.ga.us/builderv03/lptools/lpshared/lpdisplay.asp?Session_Stamp

20. Cytogenetics Title Cytogenetics and chromosomal disorders Annotation This site contains information about chromosomal disorders. Title Genetic Alliance http://www.glc.k12.ga.us/builderv03/lptools/lpshared/lpdisplay.asp?Session_Stamp

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