aneuploidy

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Related to Aneuploidies: trisomy 21, Patau syndrome, Edwards syndrome, Aneuploid cell

aneuploidy

 [an″u-ploi´de]
the state of having chromosomes in a number that is not an exact multiple of the haploid number. adj., adj an´euploid.

an·eu·ploi·d·y

(an'yū-ploy'dē),
State of being aneuploid.

aneuploidy

/an·eu·ploi·dy/ (an″u-ploi´de) any deviation from an exact multiple of the haploid number of chromosomes, whether fewer or more.

aneuploidy

[an′yoo͡ploi′dē]
any variation in chromosome number that involves individual chromosomes rather than entire sets of chromosomes. There may be fewer chromosomes, as in Turner's syndrome (one X chromosome in females), or more chromosomes, as in Down syndrome (three copies of chromosome 21). Such individuals have various abnormal physiological and morphological traits. Compare euploidy. See also chromosomal aberration, monosomy, trisomy.

an·eu·ploi·d·y

(an'yū-ploy'dē)
State of being aneuploid.

aneuploidy

An abnormality in the number of CHROMOSOMES by loss or duplication. The number may be smaller or greater than the normal diploid constitution. The loss of a whole chromosome is lethal. A chromosome extra to one of the pairs is called TRISOMY. Trisomy 21, for instance, causes DOWN'S SYNDROME. DNA aneuploidy refers to abnormal quantities of DNA in a nucleus. See also MOSAICISM.

aneuploidy

a condition where more or less than a complete set of chromosomes is found in each cell of an individual. Compare EUPLOIDY. Typically aneuploids have one extra or one missing chromosome. For example, in DOWN'S SYNDROME affected individuals have three number-21 chromosomes rather than the normal two, a condition known as TRISOMY. see CHROMOSOMAL MUTATION.

chromosome 

One of the thread-like structures located within the cell nucleus composed of an extremely long, double-stranded DNA (deoxyribonucleic acid) helix tightly folded around proteins called histones. Each chromosome carries genes that contain the hereditary material that controls the growth and characteristics of the body. There are 46 chromosomes in each human somatic cell organized in 23 pairs, of which 22 pairs are similar in appearance but differ at the molecular level. They are called autosomal chromosomes or autosomes and are designated by a number (with chromosome 1 being the longest, followed by chromosome 2, etc.). The other pair, the sex chromosomes determines the sex of the individual. In mammals the two sex chromosomes of females are alike (homologous) and are referred to as X chromosomes. Males carry one X chromosome along with a much shorter chromosome, the Y chromosome. Each chromosome has a centromere that divides it into two arms, the short arm 'p' and the long arm 'q'. Disorders of chromosome number in which the number of chromosomes is above or below the normal (46) are called aneuploidy. Common forms of aneuploidy are trisomy in which there is one extra chromosome and monosomy in which there is one less, than the normal 46. They rarely cause specific eye diseases but affected individuals present ocular manifestations. Examples: Down's syndrome (trisomy of chromosome 21), Edwards' syndrome (trisomy 18), Turner's syndrome (monosomy 45 XO). There are other chromosome abnormalities such as translocation (one segment of a chromosome is transferred to another chromosome) as may occur in congenital anterior polar cataract, deletion (a loss of a piece of chromosome) as in aniridia, choroideremia, retinoblastoma, etc. Other cases involve damage of a chromosome (e.g. fragile X syndrome). See defective colour vision; gene; mitosis; mutation.

aneuploidy

the state of having chromosomes in a number that is not an exact multiple of the haploid number; seen in karyotypes which have a small number of extra chromosomes or have a small number less than normal.
References in periodicals archive ?
Secondary findings from noninvasive prenatal testing for common fetal aneuploidies by whole genome sequencing as a clinical service.
As it stands, the Society for Maternal-Fetal Medicine and the American College of Obstetricians and Gynecologists state that the testing be used only in women at higher risk for giving birth to children with aneuploidies, such as women aged 35 years or older or those with a history of pregnancy with trisomy, and that positive cell-free DNA results should be confirmed by invasive diagnostic testing.
SCAs are present in 1 of 400 live births, a rate that is higher than the most common autosomal aneuploidies combined (59).
Despite these technical issues, there now are numerous publications reporting the use of cfDNA for non-invasive prenatal testing (NIPT) for fetal chromosomal aneuploidies.
Detection of sex chromosomal aneuploidies X-X, Y-Y, and X-Y in human sperm using two-chromosome fluorescence in situ hybridization.
A test's predictive value is used to assess whether an individual's test result is truly positive or negative (or a false positive or false negative), and may be a more important barometer of a test's clinical value than sensitivity and specificity for conditions that have a low prevalence, such as fetal aneuploidies.
This concept is exemplified in noninvasive prenatal screening, in which next-generation sequencing of free fetal DNA from maternal serum is used to detect common trisomies and sex chromosome aneuploidies.
NEW YORK, July 1, 2015 /PRNewswire/ -- Noninvasive prenatal testing (NIPT) is an advancement in the detection of fetal chromosomal aneuploidies that analyzes cell-free fetal DNA in the blood of a pregnant woman.
The available tests measure cell-free fetal DNA in the maternal blood and currently are used to detect trisomy 21, 18, and 13, as well as sex chromosome aneuploidies.
Prenatal screening for chromosomal aneuploidies is a fundamental part of routine obstetric care in most countries.
FISH studies detect commonly occurring aneuploidies with multicolor, commercially available, chromosome specific probes for chromosomes 13, 18, 21, X, and Y.