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Encyclopedia > Chromosome 15 (human)

Chromosome 15 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 15 spans about 100 million base pairs (the building material of DNA) and represents between 3 percent and 3.5 percent of the total DNA in cells. Figure 1: Chromosome. ... Binomial name Homo sapiens Linnaeus, 1758 Subspecies Homo sapiens idaltu(extinct) Homo sapiens sapiens Homo (genus). ... In molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). ... Space-filling model of a section of DNA molecule Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and most viruses). ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ...


Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 15 likely contains between 700 and 900 genes. This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ...

Contents


Genes

The following are some of the genes located on chromosome 15:

  • FAH: fumarylacetoacetate hydrolase (fumarylacetoacetase)
  • FBN1: fibrillin 1 (Marfan syndrome)
  • HEXA: hexosaminidase A (alpha polypeptide)
  • IVD: isovaleryl Coenzyme A dehydrogenase
  • OCA2: oculocutaneous albinism II (pink-eye dilution homolog, mouse)
  • RAD51: RAD51 homolog (RecA homolog, E. coli) (S. cerevisiae)
  • STRC: stereocilin
  • UBE3A: ubiquitin protein ligase E3A (human papilloma virus E6-associated protein, Angelman syndrome)

The intra vas device is a proposed contraceptive device for men, analogous to the IUD for women. ...

Diseases

The following diseases are some of those related to genes on chromosome 15:

Angelman syndrome (AS) is neurological disorder in which severe learning difficulties are associated with a characteristic facial appearance and behavior. ... Breast cancer is cancer of breast tissue. ... Isovaleric acidemia is a rare genetic disorder in which the body is unable to process certain proteins properly. ... Marfan syndrome is a connective tissue disorder characterized by unusually long limbs. ... Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. ... Prader-Willi syndrome is a genetic disorder in which seven genes (or some subset thereof) on chromosome 15 are missing or unexpressed (chromosome 15q partial deletion). ... Tay-Sachs disease (abbreviated TSD, also known as GM2 gangliosidosis) is a fatal genetic disorder, inherited in an autosomal recessive pattern, in which harmful quantities of a fatty substance called ganglioside GM2 accumulate in the nerve cells in the brain. ... Tyrosinemia is an error of metabolism, usually inborn, in which the body can not effectively break down the amino acid tyrosine, found in most animal and plant proteins. ...

Chromosomal conditions

The following conditions are caused by changes in the structure or number of copies of chromosome 15:

  • Angelman syndrome: Angelman syndrome results from a loss of gene activity in a specific part of chromosome 15, the 15q11-q13 region. This region contains a gene called UBE3A that, when mutated or absent, likely causes the characteristic features of this condition. People normally have two copies of the UBE3A gene, one from each parent. Both copies of this gene are active in many of the body's tissues. In the brain, however, only the copy inherited from a person's mother (the maternal copy) is active. If the maternal copy is lost because of a chromosomal change or a gene mutation, a person will have no working copies of the UBE3A gene in the brain.

In most cases (about 70 percent), people with Angelman syndrome have a deletion in the maternal copy of chromosome 15. This chromosomal change deletes the region of chromosome 15 that includes the UBE3A gene. Because the copy of the UBE3A gene inherited from a person's father (the paternal copy) is normally inactive in the brain, a deletion in the maternal chromosome 15 results in no active copies of the UBE3A gene in the brain. Angelman syndrome (AS) is neurological disorder in which severe learning difficulties are associated with a characteristic facial appearance and behavior. ...


In 3 percent to 7 percent of cases, Angelman syndrome occurs when a person has two copies of the paternal chromosome 15 instead of one copy from each parent. This phenomenon is called paternal uniparental disomy (UPD). People with paternal UPD for chromosome 15 have two copies of the UBE3A gene, but they are both inherited from the father and are therefore inactive in the brain.


About 10 percent of Angelman syndrome cases are caused by a mutation in the UBE3A gene, and another 3 percent result from a defect in the DNA region that controls the activation of the UBE3A gene and other genes on the maternal copy of chromosome 15. In a small percentage of cases, Angelman syndrome may be caused by a chromosomal rearrangement called a translocation or by a mutation in a gene other than UBE3A. These genetic changes can abnormally inactivate the UBE3A gene.

  • Prader-Willi syndrome: Prader-Willi syndrome is caused by the loss of active genes in a specific part of chromosome 15, the 15q11-q13 region. People normally have two copies of this chromosome in each cell, one copy from each parent. Prader-Willi syndrome occurs when the paternal copy is partly or entirely missing. Researchers are working to identify genes on chromosome 15 that are responsible for the characteristic features of Prader-Willi syndrome.

In about 70 percent of cases, Prader-Willi syndrome occurs when the 15q11-q13 region of the paternal chromosome 15 is deleted. The genes in this region are normally active on the paternal copy of the chromosome and are inactive on the maternal copy. Therefore, a person with a deletion in the paternal chromosome 15 will have no active genes in this region. Prader-Willi syndrome is a genetic disorder in which seven genes (or some subset thereof) on chromosome 15 are missing or unexpressed (chromosome 15q partial deletion). ...


In about 25 percent of cases, a person with Prader-Willi syndrome has two maternal copies of chromosome 15 in each cell instead of one copy from each parent. This phenomenon is called maternal uniparental disomy. Because some genes are normally active only on the paternal copy of this chromosome, a person with two maternal copies of chromosome 15 will have no active copies of these genes.


In a small percentage of cases, Prader-Willi syndrome is caused by a chromosomal rearrangement called a translocation. Rarely, the condition is caused by an abnormality in the DNA region that controls the activity of genes on the paternal chromosome 15.

  • Other chromosomal conditions: A specific chromosomal change called an isodicentric chromosome 15 (previously called an inverted duplication 15) can affect growth and development. This small extra chromosome is made up of genetic material from chromosome 15 that has been abnormally duplicated (copied) and attached end-to-end. In some cases, the extra chromosome is very small and has no effect on a person's health. A larger isodicentric chromosome 15 can result in weak muscle tone (hypotonia), mental retardation, seizures, and behavioral problems. Signs and symptoms of autism (a developmental disorder that affects communication and social interaction) have also been associated with the presence of an isodicentric chromosome 15.

Other changes in the number or structure of chromosome 15 can cause mental retardation, delayed growth and development, hypotonia, and characteristic facial features. These changes include an extra copy of part of chromosome 15 in each cell (partial trisomy 15) or a missing segment of the chromosome in each cell (partial monosomy 15). In some cases, several of the chromosome's DNA building blocks (nucleotides) are deleted or duplicated.


References

  • Bittel DC, Butler MG (2005). Prader-Willi syndrome: clinical genetics, cytogenetics and molecular biology. Expert Rev Mol Med 7 (14): 1-20. PMID 16038620
  • Bittel DC, Kibiryeva N, Talebizadeh Z, Butler MG (2003). Microarray analysis of gene/transcript expression in Prader-Willi syndrome: deletion versus UPD. J Med Genet 40 (8): 568-74. PMID 12920063
  • Bittel DC, Kibiryeva N, Talebizadeh Z, Driscoll DJ, Butler MG (2005). Microarray analysis of gene/transcript expression in Angelman syndrome: deletion versus UPD. Genomics 85 (1): 85-91. PMID 15607424
  • Borgatti R, Piccinelli P, Passoni D, Dalpra L, Miozzo M, Micheli R, Gagliardi C, Balottin U (2001). Relationship between clinical and genetic features in "inverted duplicated chromosome 15" patients. Pediatr Neurol 24 (2): 111-6. PMID 11275459
  • Butler MG, Bittel DC, Kibiryeva N, Talebizadeh Z, Thompson T (2004). Behavioral differences among subjects with Prader-Willi syndrome and type I or type II deletion and maternal disomy. Pediatrics 113 (3 Pt 1): 565-73. PMID 14993551
  • Cassidy SB, Dykens E, Williams CA (2000). Prader-Willi and Angelman syndromes: sister imprinted disorders. Am J Med Genet 97 (2): 136-46. PMID 11180221
  • Clayton-Smith J, Laan L (2003). Angelman syndrome: a review of the clinical and genetic aspects. J Med Genet 40 (2): 87-95. PMID 12566516
  • Gilbert F (1999). Disease genes and chromosomes: disease maps of the human genome. Chromosome 15. Genet Test 3 (3): 309-22. PMID 10495933
  • Lee S, Wevrick R (2000). Identification of novel imprinted transcripts in the Prader-Willi syndrome and Angelman syndrome deletion region: further evidence for regional imprinting control. Am J Hum Genet 66 (3): 848-58. PMID 10712201
  • Rineer S, Finucane B, Simon EW (1998). Autistic symptoms among children and young adults with isodicentric chromosome 15. Am J Med Genet 81 (5): 428-33. PMID 9754629
  • Zollino M, Tiziano F, Di Stefano C, Neri G (1999). Partial duplication of the long arm of chromosome 15: confirmation of a causative role in craniosynostosis and definition of a 15q25-qter trisomy syndrome. Am J Med Genet 87 (5): 391-4. PMID 10594876
Human chromosomes edit

{1} {2} {3} {4} {5} {6} {7} {8} {9} {10} {11} {12} {13} {14} {15} {16} {17} {18} {19} {20} {21} {22} {X} {Y} Figure 1: Chromosome. ... Chromosome 10 is one of the 23 pairs of chromosomes in humans. ... Chromosome 11 is one of the 23 pairs of chromosomes in humans. ... Chromosome 12 is one of the 23 pairs of chromosomes in humans. ... Chromosome 13 is one of the 23 pairs of chromosomes in humans. ... Chromosome 14 is one of the 23 pairs of chromosomes in humans. ... A common disease due to 3 of such chromosomes instead of the normal 2 is called Down syndrome. ... The human X chromosome, is is one of the two chromosomes involved in the XY sex-determination system. ... The human Y chromosome is one of two sex chromosomes, it contains the genes that cause testis development, thus determining maleness. ...


  Results from FactBites:
 
Human Chromosome 15 (93 words)
A chromosome is a treadlike linear strand of DNA found in the nucleus of a cell that carries the genes in the transmission of hereditary information.
Humans have 46 chromosomes: 22 homologous pairs and either XX (females) or XY (males).
This webpage is devoted to Chromosome 15 and the diseases and proteins associated with it.
Chromosome 15 Ring (767 words)
Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring.
Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females.
Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.
  More results at FactBites »

 
 

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