Beispiel | Beispiel | <section> <templateId root="2.16.840.1.113883.10.20.20.1.9"/> <title>Test Information</title> <component> <section> <templateId root="2.16.840.1.113883.10.20.20.1.9.1"/> <title>Background</title> <text> <list> <item> <content> Mutations in the GJB2 (connexin 26) gene are the most common cause of non syndromic hearing loss and are most often seen in a person with hearing loss that was found in early childhood without any other medical problems. The severity of the hearing loss can range from mild to profound. The inheritance pattern is usually autosomal recessive, requiring two mutations, one in each copy of the gene, to cause hearing loss. The GJB6- D13S1830 deletion removes most of the GJB6 gene, which encodes the connexin 30 protein (Cx30). This deletion, when present in two copies or when combined with a single connexin 26 mutation, causes hearing loss. Although the frequency of mitochondrial hearing loss is unknown, studies suggest that mitochondrial mutations play an important role in inherited and acquired hearing impairment. </content> </item> </list> </text> </section> </component> <component> <section> <templateId root="2.16.840.1.113883.10.20.20.1.9.2"/> <title>Methodology</title> <text> <list> <item> <content> Exon 1 and the coding region of exon 2 of the connexin 26 (GJB2) gene are amplified using flanking primer sets. PCR products are sequenced using an ABI fluorescence automatic DNA sequencer. This test does not detect large deletions or mutations in non-coding regions that could affect gene expression. This assay is greater than 99.9% accurate in detecting mutations in the sequences analyzed. Polymerase chain reaction (PCR) analysis is performed to detect the presence or absence of a deletion spanning the GJB6-D13S1830 region of chromosome 13. </content> </item> </list> </text> </section> </component> <component> <section> <templateId root="2.16.840.1.113883.10.20.20.1.9.3"/> <title>References</title> <text> <list> <item> <content> Azaiez H, Chamberlin GP, Fischer SM, Welp CL, Prasad SD, Taggart RT, del Castillo, I, Van Camp G and Smith RJ. GJB2: the spectrum of deafnesscausing allele variants and their phenotype. Hum Mutat. 2004;24(4): 305-11. </content> </item> <item> <content> Calvo J, Rabionet R, Gasparini P, Estivill X. Connexins and Deafness Homepage. http://www.crg.es/deafness. </content> </item> <item> <content> del Castillo I, Moreno-Pelayo MA, del Castillo FJ, Brownstein Z, Marlin S, Adina Q, Cockburn DJ, Pandya A, Siemering KR, Chamberlin GP, Ballana E, Wuyts W, Maciel-Guerra AT, Alvarez A, Villamar M, Shohat M, Abeliovich D, Dahl HH, Estivill X, Gasparini P, Hutchin T, Nance WE, Sartorato EL, Smith RJ, Van Camp G, Avraham KB, Petit C. and Moreno F. Prevalence and evolutionary origins of the del(GJB6-D13S1830) mutation in the DFNB1 locus in hearing-impaired subjects: a multicenter study. Am J Hum Genet. 2003;73: 1452-1458. </content> </item> <item> <content> Kelley PM, Harris DJ, Comer BC, Askew JW, Fowler T, Smith SD, Kimberling WJ. Novel mutations in the connexin 26 gene (GJB2) that cause autosomal recessive (DFNB1) hearing loss. Am J Hum Genet. 1998 Apr;62(4):792-9. </content> </item> <item> <content> Kenna MA, Wu BL, Cotanche DA, Korf BR, Rehm HL. Connexin 26 studies in patients with sensorineural hearing loss. Arch Otolaryngol Head Neck Surg. 2001 Sep;127(9):1037-42. </content> </item> <item> <content> Kenneson A, Van Naarden Braun K and Boyle C. GJB2 (connexin 26) variants and nonsyndromic sensorineural hearing loss: a HuGE review. Genet Med. 2002;4(4): 258-74. </content> </item> <item> <content> Park HJ, Hahn SH, Chun YM, Park K, Kim HN. Connexin26 mutations associated with nonsyndromic hearing loss. Laryngoscope. 2000 Sep;110(9):1535-8. </content> </item> <item> <content> Rickard S, Kelsell DP, Sirimana T, Rajput K, MacArdle B, Bitner-Glindzicz M. Recurrent mutations in the deafness gene GJB2 (connexin 26) in British Asian families. J Med Genet. 2001 Aug;38(8):530-3. </content> </item> <item> <content> Smith RJH, Van Camp G. Nonsyndromic hearing loss and deafness, DFNB1 (Updated March 14, 2005) In: GeneReviews at GeneTests: Medical Genetics Information Resource (database online). http://www.genetests.org. </content> </item> <item> <content> Snoeckx RL, Huygen PLM, Feldmann D, Marlin S, Denoyelle F, Waligora J, Mueller-Malesinska M, Pollak A, Ploski R, Murgia A, Orzan E, Castorina P, Ambrosetti U, Nowakowska-Szyrwinska E, Bal J, Wiszniewski W, Janecke AR, Nekahm-Heis D, Seeman P, Bendova O, Kenna MA, Frangulov A, Rehm HL, Tekin M, Incesulu A, Dahl H-HM, du Sart D, Jenkins L, Lucas D, Bitner-Glindzicz M, Avraham KB, Brownstein Z, del Castillo I, Moreno F, Blin N, Pfister M, Sziklai I, Toth T, Kelley PM, Cohn ES, Maldergem LV, Hilbert P, Roux A-F, Mondain M, Hoefsloot, LH Cremers CWRJ, Lopponen T, Lopponen H, Parving A, Gronskov K, Schrijver I, Roberson J, Gualandi F, Martini A, Lina-Granade G, Pallares-Ruiz N, Correia C, Fialho G, Cryns K, Hilgert N, Van de Heyning P, Nishimura CJ, Smith RJH, and Van Camp G. A genotype-phenotype correlation for GJB2 (connexin 26) deafness. Am J Med Genet 2005 Dec;77(6):945-57. </content> </item> </list> </text> </section> </component></section> |
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