A novel DFNB1 deletion allele supports the existence of a distant cis-regulatory region that controls GJB2 and GJB6 expression
Article first published online: 11 FEB 2010
© 2010 John Wiley & Sons A/S
Volume 78, Issue 3, pages 267–274, September 2010
How to Cite
Wilch, E., Azaiez, H., Fisher, R., Elfenbein, J., Murgia, A., Birkenhäger, R., Bolz, H., Da Silva-Costa, S., Del Castillo, I., Haaf, T., Hoefsloot, L., Kremer, H., Kubisch, C., Le Marechal, C., Pandya, A., Sartorato, E., Schneider, E., Van Camp, G., Wuyts, W., Smith, R. and Friderici, K. (2010), A novel DFNB1 deletion allele supports the existence of a distant cis-regulatory region that controls GJB2 and GJB6 expression. Clinical Genetics, 78: 267–274. doi: 10.1111/j.1399-0004.2010.01387.x
- Issue published online: 3 AUG 2010
- Article first published online: 11 FEB 2010
- Received 4 December 2009, revised and accepted for publication 18 January 2010
- connexin 26;
- connexin 30;
- gene expression regulation;
- sensorineural hearing loss;
- sequence deletion
Wilch E, Azaiez H, Fisher RA, Elfenbein J, Murgia A, Birkenhäger R, Bolz HJ, da Silva-Costa SM, del Castillo I, Haaf T, Hoefsloot L, Kremer H, Kubisch C, Le Marechal C, Pandya A, Sartorato EL, Schneider E, Van Camp G, Wuyts W, Smith RJH, Friderici KH. A novel DFNB1 deletion allele supports the existence of a distant cis-regulatory region that controls GJB2 and GJB6 expression.
Eleven affected members of a large German–American family segregating recessively inherited, congenital, non-syndromic sensorineural hearing loss (SNHL) were found to be homozygous for the common 35delG mutation of GJB2, the gene encoding the gap junction protein Connexin 26. Surprisingly, four additional family members with bilateral profound SNHL carried only a single 35delG mutation. Previously, we demonstrated reduced expression of both GJB2 and GJB6 mRNA from the allele carried in trans with that bearing the 35delG mutation in these four persons. Using array comparative genome hybridization (array CGH), we have now identified on this allele a deletion of 131.4 kb whose proximal breakpoint lies more than 100 kb upstream of the transcriptional start sites of GJB2 and GJB6. This deletion, del(chr13:19,837,344–19,968,698), segregates as a completely penetrant DFNB1 allele in this family. It is not present in 528 persons with SNHL and monoallelic mutation of GJB2 or GJB6, and we have not identified any other candidate pathogenic copy number variation by arrayCGH in a subset of 10 such persons. Characterization of distant GJB2/GJB6 cis-regulatory regions evidenced by this allele may be required to find the ‘missing’ DFNB1 mutations that are believed to exist.