Chromosome 13 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 13 spans about 113 million base pairs (the building material of DNA) and represents between 3.5 and 4% of the total DNA in cells.
Genes Number of genes The following are some of the gene count estimates of human chromosome 13. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.
Estimated by Protein-coding genes Non-coding RNA genes Pseudogenes Source Release date CCDS 308 — — 2016-09-08 HGNC 309 323 469 2017-05-12 Ensembl 324 586 373 2017-03-29 UniProt 329 — — 2018-02-28 NCBI 343 622 481 2017-05-19
Gene list
The following is a partial list of genes on human chromosome 13. For complete list, see the link in the infobox on the right.
Diseases and disorders The following diseases and disorders are some of those related to genes on chromosome 13:
13q deletion syndrome Bipolar disorder Bladder cancer Breast cancer Heterochromia Hirschsprung's disease Maturity onset diabetes of the young type 4 Nonsyndromic deafness Propionic acidemia Retinoblastoma Schizophrenia Waardenburg syndrome Wilson's disease Patau syndrome Chronic lymphocytic leukemia (Acquired defect) Young–Madders syndrome
Chromosomal conditions The following conditions are caused by changes in the structure or number of copies of chromosome 13:
Retinoblastoma: A small percentage of retinoblastoma cases are caused by deletions in the region of chromosome 13 (13q14) containing the RB1 gene. Children with these chromosomal deletions may also have intellectual disability, slow growth, and characteristic facial features (such as prominent eyebrows, a broad nasal bridge, a short nose, and ear abnormalities). Researchers have not determined which other genes are located in the deleted region, but a loss of several genes is likely responsible for these developmental problems. Trisomy 13: Trisomy 13 occurs when each cell in the body has three copies of chromosome 13 instead of the usual two copies. Trisomy 13 can also result from an extra copy of chromosome 13 in only some of the body's cells (mosaic trisomy 13). In a small percentage of cases, trisomy 13 is caused by a rearrangement of chromosomal material between chromosome 13 and another chromosome. As a result, a person has the two usual copies of chromosome 13, plus extra material from chromosome 13 attached to another chromosome. These cases are called translocation trisomy 13. Extra material from chromosome 13 disrupts the course of normal development, causing the characteristic signs and symptoms of trisomy 13. Researchers are not yet certain how this extra genetic material leads to the features of the disorder, which include severely abnormal cerebral functions, a small cranium, retardation, non functional eyes and heart defects. Other chromosomal conditions: Partial monosomy 13q is a rare chromosomal disorder that results when a piece of the long arm (q) of chromosome 13 is missing (monosomic). Infants born with partial monosomy 13q may exhibit low birth weight, malformations of the head and face (craniofacial region), skeletal abnormalities (especially of the hands and feet), and other physical abnormalities. Intellectual disability is characteristic of this condition. The mortality rate during infancy is high among individuals born with this disorder. Almost all cases of partial monosomy 13q occur randomly for no apparent reason (sporadic).
Cytogenetic band
+ G-bands of human chromosome 13 in resolution 850 bphs Chr. Arm"p": Short arm; "q": Long arm. BandFor cytogenetic banding nomenclature, see article locus. ISCNstartThese values (ISCN start/stop) are based on the length of bands/ideograms from the ISCN book, An International System for Human Cytogenetic Nomenclature (2013). Arbitrary unit. ISCNstop Basepairstart Basepairstop Staingpos: Region which is positively stained by G banding, generally AT-rich and gene poor; gneg: Region which is negatively stained by G banding, generally CG-rich and gene rich; acen Centromere. var: Variable region; stalk: Stalk. Density 13 p 13 0 282 gvar 13 p 12 282 620 stalk 13 p 11.2 620 1015 gvar 13 p 11.1 1015 1198 acen 13 q 11 1198 1353 acen 13 q 12.11 1353 1536 gneg 13 q 12.12 1536 1635 gpos 25 13 q 12.13 1635 1790 gneg 13 q 12.2 1790 1888 gpos 25 13 q 12.3 1888 2114 gneg 13 q 13.1 2114 2255 gpos 50 13 q 13.2 2255 2367 gneg 13 q 13.3 2367 2649 gpos 75 13 q 14.11 2649 2931 gneg 13 q 14.12 2931 3030 gpos 25 13 q 14.13 3030 3128 gneg 13 q 14.2 3128 3311 gpos 50 13 q 14.3 3311 3537 gneg 13 q 21.1 3537 3762 gpos 100 13 q 21.2 3762 3889 gneg 13 q 21.31 3889 4058 gpos 75 13 q 21.32 4058 4199 gneg 13 q 21.33 4199 4439 gpos 100 13 q 22.1 4439 4565 gneg 13 q 22.2 4565 4678 gpos 50 13 q 22.3 4678 4791 gneg 13 q 31.1 4791 5087 gpos 100 13 q 31.2 5087 5171 gneg 13 q 31.3 5171 5355 gpos 100 13 q 32.1 5355 5510 gneg 13 q 32.2 5510 5636 gpos 25 13 q 32.3 5636 5834 gneg 13 q 33.1 5834 5989 gpos 100 13 q 33.2 5989 6087 gneg 13 q 33.3 6087 6256 gpos 100 13 q 34 6256 6510 gneg
References
External links