Chromosome 7 (human)

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Chromosome 7.svg

Chromosome 7 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 7 spans about 159 million[1] base pairs (the building material of DNA) and represents between 5 and 5.5 percent of the total DNA in cells.

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 7 is likely to contain between 1,000 and 1,400 genes. It also contains the Homeobox A gene cluster.[2]

Diseases and disorders[edit]

The following diseases are some of those related to genes on chromosome 7:

Chromosomal disorders[edit]

The following conditions are caused by changes in the structure or number of copies of chromosome 7:

  • Williams syndrome is caused by the deletion of genetic material from a portion of the long (q) arm of chromosome 7. The deleted region, which is located at position 11.23 (written as 7q11.23), is designated as the Williams syndrome critical region. This region includes more than 20 genes, and researchers believe that the characteristic features of Williams syndrome are probably related to the loss of multiple genes in this region.

While a few of the specific genes related to Williams syndrome have been identified, the relationship between most of the genes in the deleted region and the signs and symptoms of Williams syndrome is unknown.

  • Other changes in the number or structure of chromosome 7 can cause delayed growth and development, mental disorder, characteristic facial features, skeletal abnormalities, delayed speech, and other medical problems. These changes include an extra copy of part of chromosome 7 in each cell (partial trisomy 7) or a missing segment of the chromosome in each cell (partial monosomy 7). In some cases, several DNA building blocks (nucleotides) are deleted or duplicated in part of chromosome 7. A circular structure called ring chromosome 7 is also possible. A ring chromosome occurs when both ends of a broken chromosome are reunited.[12]

References[edit]

  1. ^ What is chromosome 7, "Genetics Home Reference" of U.S. National Library of Medicine. April 2008. [2014-05-14].
  2. ^ a b c Hillier LW, Fulton RS, Fulton LA, Graves TA, Pepin KH,et al. (2003). "The DNA sequence of human chromosome 7". Nature 424 (6945): 157–64. doi:10.1038/nature01782. PMID 12853948.  * Lichtenbelt KD, Hochstenbach R, van Dam WM, Eleveld MJ, Poot M, Beemer FA (2005). "Supernumerary ring chromosome 7 mosaicism: case report, investigation of the gene content, and delineation of the phenotype". Am J Med Genet A 132 (1): 93–100. doi:10.1002/ajmg.a.30408. PMID 15580634. 
  3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y Scherer SW, Cheung J, MacDonald JR, Osborne LR, Nakabayashi K, Herbrick JA, Carson AR, et al. (2003). "Human chromosome 7: DNA sequence and biology". Science 300 (5620): 767–72. doi:10.1126/science.1083423. PMC 2882961. PMID 12690205. 
  4. ^ Nagamani SC, Erez A, Lee B (May 2012). "Argininosuccinate lyase deficiency". Genet. Med. 14 (5): 501–7. doi:10.1038/gim.2011.1. PMC 3709024. PMID 22241104. 
  5. ^ a b c d e Gilbert F (2002). "Chromosome 7". Genet Test 6 (2): 141–61. doi:10.1089/10906570260199429. PMID 12215256. 
  6. ^ a b Newbury DF, Monaco AP (October 2010). "Genetic advances in the study of speech and language disorders". Neuron 68 (2): 309–20. doi:10.1016/j.neuron.2010.10.001. PMC 2977079. PMID 20955937. 
  7. ^ Solé E et al (2000). "Incidence, characterization and prognostic significance of chromosomal abnormalities in 640 patients with primary myelodysplastic syndromes". British Journal of Haematology 108 (2): 346–356. doi:10.1046/j.1365-2141.2000.01868.x. PMID 10691865. 
  8. ^ Lossin C, George AL (2008). "Myotonia congenita". Adv. Genet. 63: 25–55. doi:10.1016/S0065-2660(08)01002-X. PMID 19185184. 
  9. ^ Grimaldi R, Capuano P, Miranda N, Wagner C, Capasso G (2007). "[Pendrin: physiology, molecular biology and clinical importance]". G Ital Nefrol (in Italian) 24 (4): 288–94. PMID 17659500. 
  10. ^ Eggermann T, Begemann M, Binder G, Spengler S (2010). "Silver-Russell syndrome: genetic basis and molecular genetic testing". Orphanet J Rare Dis 5: 19. doi:10.1186/1750-1172-5-19. PMC 2907323. PMID 20573229. 
  11. ^ Zarchi O, Attias J, Gothelf D (2010). "Auditory and visual processing in Williams syndrome". Isr J Psychiatry Relat Sci 47 (2): 125–31. PMID 20733255. 
  12. ^ Velagaleti GV, Jalal SM, Kukolich MK, Lockhart LH, Tonk VS (2002). "De novo supernumerary ring chromosome 7: first report of a non-mosaic patient and review of the literature". Clin Genet 61 (3): 202–6. doi:10.1034/j.1399-0004.2002.610306.x. PMID 12000362. 

Further reading[edit]

  • Rodriguez L, Lopez F, Paisan L, de la Red Mdel M, Ruiz AM, Blanco M, Antelo Cortizas J, Martinez-Frias ML (2002). "Pure partial trisomy 7q: two new patients and review". Am J Med Genet 113 (2): 218–24. doi:10.1002/ajmg.10719. PMID 12407716. 

External links[edit]