Definition

Noun: A chromosomal abnormality characterized by an abnormal number of chromosomes in a cell. The number is not an exact multiple of the haploid number (the basic set of chromosomes), meaning one or more individual chromosomes are missing or present in extra copies, disrupting the normal chromosomal complement.

Usage and Examples

• The condition is caused by aneuploidy, specifically the presence of an extra copy of chromosome 21.
• Screening tests during pregnancy can assess the risk of fetal aneuploidy.
• Aneuploidy is a common feature of many cancer cells.

Advanced Usage and Context

• "Constitutional aneuploidy": Refers to aneuploidy present in all cells of an individual's body, typically arising from an error in gamete (sperm or egg) formation or early embryonic development. Examples include Down syndrome (trisomy 21).
• "Somatic or mosaic aneuploidy": Refers to aneuploidy that occurs in some but not all cells of the body, often due to errors in cell division (mitosis) after conception. This can lead to varying degrees of clinical presentation.
• "Aneuploidy screening": A medical process, such as non-invasive prenatal testing (NIPT), used to estimate the risk of common fetal aneuploidies.

Variants and Related Words

• Aneuploid (adjective): Describing a cell or organism that has an abnormal number of chromosomes.
  • The analysis revealed an aneuploid cell line.
• Euploidy (noun): The state of having a complete set of chromosomes in exact multiples of the haploid number (e.g., haploid, diploid). This is the normal, balanced state.
• Trisomy (noun): A type of aneuploidy where there are three copies of a particular chromosome instead of the usual two.
• Monosomy (noun): A type of aneuploidy where there is only one copy of a particular chromosome instead of the usual two.

Synonyms and Near-Synonyms

• Chromosomal numerical abnormality
• Heteroploidy (a broader term that includes both aneuploidy and polyploidy)

Antonyms

• Euploidy
• Diploidy (the state of having two complete sets of chromosomes, the normal condition for most human somatic cells)

Noun

1. an abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)