abnormal number of chromosomes mainly (90%) due to chromosome malsegregation mechanisms in maternal meiosis I. (More? Trisomy 21 | Meiosis)
The condition of a cell or of an organism that has additions or deletions of a small number of whole chromosomes from the expected balanced diploid number of chromosomes.
an abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)
An abnormal number of chromosomes (usually 46 in a body cell) due to there being extra or missing chromosomes
The loss or gain of one or two chromosomes. In a healthy human, all cells have 46 chromosomes, but occasionally around fertilisation time mistakes sometimes occur which result in each cell having e.g. 44,45,47 or 48 chromosomes. An embryo with only 44 or fewer chromosomes never survives the whole pregnancy and is lost by spontaneous miscarriage. Most of the other abnormal numbers do also, but some do go to full term pregnancy. The best-known and most frequent examples of aneuploidy results in a Down's syndrome baby.
The occurrence of one or more extra or missing chromosomes leading to an unbalanced chromosome complement, or, any chromosome number that is not an exact multiple of the haploid number
Abnormal number of chromosomes within a cell.
Having an abnormal number of chromosomes
The presence of extra chromosomes, such that the chromosomal composition of a cell is not an exact multiple of the haploid set.
("not/good/fold"): a condition in which the chromosome number of an individual is not an exact multiple of the typical haploid set for the species. chromosome duplication : single chromosome duplication, instead of a whole genome duplication.
Variation in chromosome number involving one or a small number of chromosomes; commonly involves the gain or loss of a single chromosome.
having an abnormal set of chromosomes
Any deviation from an exact multiple of the haploid number (a single set of nonhomologous chromosomes in human is 23) of chromosomes, whether fewer or more.
chromosome number is not a multiple of the normal haploid (23), usually caused by random erros in meiosis or mitosis
a chromosome problem that happens when one or more whole chromosomes either are missing or are present in more than the typical number of copies.
The loss or gain of a chromosome resulting from non-disjunction, usually in meiosis. It normally refers to whole chromosomes but may be used in relation to extra parts of chromosomes.
Extra or missing chromosomes; other than the normal number of each per cell.
the circumstances in which the total number of chromosomes within a cell is not an exact multiple of the normal haploid (see polyploidy) number. Chromosomes may be lost or gained during cell division.
an evolutionary change in chromosome number not in multiples of the haploid genome.
fewer or more chromosomes than an exact mutliple of the haploid number
Abnormal number of chromasomes in an organism due to chromasomes failing to separate in meiosis.
The gain or loss of one or more chromosomes at meiosis, including trisomy (47 chromosomes) and monosomy (45 chromosomes). Caused by chromosomal nondisjunction.
Aneuploidy is a condition in which the number of chromosomes is abnormal due to extra or missing chromosomes, in other words, it is a chromosomal state where the number of chromosomes is not a multiple of the haploid set. Normal diploid species have 2n chromosomes, where n is the number in the haploid set. Aneuploid individuals would have 2n-1 chromosomes (monosomy), 2n+1 chromosomes (trisomy), or some other such arrangement.
