Chromosome 13 humain

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. 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. Genes on human chromosome 13 The following is a partial list of genes on human chromosome 13. For complete list, see the link in the infobox on the right. The following diseases and disorders are some of those related to genes on chromosome 13: 13q deletion syndrome 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 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.