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Trisomy 9. Full trisomy 9 is a rare and fatal chromosomal disorder caused by having three copies ( trisomy) of chromosome number 9. It can be a viable condition if trisomy affects only part of the cells of the body ( mosaicism) or in cases of partial trisomy (trisomy 9p) in which cells have a normal set of two entire chromosomes 9 plus part of ...
Trisomy. Example of trisomy 21 detected via qPCR short tandem repeat analysis. Specialty. Medical genetics. A trisomy is a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. [ 1] A trisomy is a type of aneuploidy (an abnormal number of chromosomes).
The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in trisomy 21. [91] [96] In 1–2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as mosaic Down syndrome.
The trisomy 21 karyotype figure shows the chromosomal arrangement, with the prominent extra chromosome 21. Trisomy 21 is the cause of approximately 95% of observed Down syndrome, with 88% coming from nondisjunction in the maternal gamete and 8% coming from nondisjunction in the paternal gamete. [4]
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. [ 1][ 2] It does not include a difference of one or more complete sets of chromosomes. A cell with any number of complete chromosome sets is called a euploid cell.
Medical genetics. Monosomy 9p (also known as Alfi's Syndrome or simply 9P-) is a rare chromosomal disorder in which some DNA is missing or has been deleted on the short arm region, "p", of one copy of chromosome 9 (9p22.2-p23). [1] [2] This deletion either happens de novo or as a result of a parent having the chromosome abnormality. [3]
Trisomy X, also known as triple X syndrome and characterized by the karyotype [ note 1] 47,XXX, is a chromosome disorder in which a female has an extra copy of the X chromosome. It is relatively common and occurs in 1 in 1,000 females, but is rarely diagnosed; fewer than 10% of those with the condition know they have it.
Turner syndrome ( TS ), also known as 45,X, or 45,X0, is a genetic disorder in which a person's cells have only one X chromosome or are partially missing an X chromosome ( sex chromosome monosomy) leading to the complete or partial deletion of the pseudoautosomal regions (PAR1, PAR2) in the affected X chromosome. [ 2][ 6][ 7] Most people have ...