The presence of three chromosomes instead of the two that normally represent each potential set of chromosomes. This can result in a developmental disability. An example of trisomy is down syndrome, in which three number 21 chromosomes are present.
The condition of having three of a certain chromosome instead of just two.
One or more than the normal number of chromosomes.
The presence of an additional third chromosome of a particular chromosome pair is caused by improper splitting (nondisjunction) of the cell nucleus during cell division trisomy 21; Down’s syndrome.
A condition in which someone has three chromosomes instead of a pair.
A type of chromosomal abnormality in which a person has three copies of a chromosome instead of the normal two. Among the most common types are trisomy 21, or Down’s syndrome; trisomy 13, or Patau’s syndrome; and trisomy 18, or Edwards’ Syndrome.
Condition in which one more than the normal number of two chromosomes exists in a cell. This chromosomal aberration is associated with many congenital defects, the type and severity of the abnormal condition depending on which chromosome is affected. Trisomy 21, for example, is Down’s syndrome.
A state in which an individual or a cell carries an extra chromosome. Normally chromosomes exist in pairs; in trisomy, there are three copies of a given chromosome. In humans, trisomy occurs when a cell carries 47 chromosomes instead of 46. For example, in trisomy 21, which causes Down syndrome, there is an extra chromosome 21. Trisomy causes a higher rate of miscarriage.
A condition in which there is one extra chromosome present in each cell in addition to the normal (diploid) chromosome set. A number of chromosome disorders are due to trisomy, including Down’s syndrome and Klinefelter ‘s syndrome.
In genetics, having three homologous chromosomes per cell instead of two.
Where three chromosomes are in a group instead of the normal pair.
A disorder characterized by the inheritance of a third copy of a chromosome, whereas the normal inheritance pattern involves only two copies.
A condition where a person’s cells contain an additional chromosome, resulting in three copies of a specific chromosome instead of the typical two.
An error in meiosis, the process of cell division that produces egg or sperm cells, can occasionally lead to an egg or sperm carrying an extra chromosome. If such an egg or sperm is involved in fertilization, the resulting embryo will have an extra chromosome in each of its cells.
The most frequent form of trisomy involves an extra copy of chromosome 21, leading to Down syndrome. Less common are trisomies 18 and 13, known as Edward’s syndrome and Patau’s syndrome, respectively. Trisomies 8 and 22 are exceedingly rare. Partial trisomy, where only a segment of a chromosome is duplicated, is also possible.
Full trisomies often lead to issues like skeletal and heart anomalies, as well as cognitive impairments. With the exception of Down syndrome, infants usually do not survive past early childhood. The impact of partial trisomies varies, depending on the extent of the additional chromosomal material.\
Diagnosis is typically confirmed through chromosome analysis, using cells collected either from the fetus via amniocentesis or after birth. No targeted treatments are available. Parents with an affected child may consider undergoing genetic counseling.