The deafness gene

The deafness gene


The mutation of MicroRNA mir-96 leads to progressive loss of hearing if present in single copy, and deafness if present in two copies

The journal Nature Genetics have posted the results of a search conducted under the projects "Sirocco" and "Eurohear", funded by the European Union. The discovery concerns the association between a new type of gene and the progressive loss of hearing, because the mir-96 gene is a small piece of RNA that affect the process of generation of other molecules in sensory hair cells of the inner ear .

The results come from the collaboration of two research groups, one Spanish and one English.

Karen Steel, one of the coordinators of the team of British Sanger Institute, said "We were able to demonstrate relatively quickly if the mice that were carriers of one copy of the variant of this gene suffer from progressive loss of hearing, and if they were carrying both genes, they were suffering from severe hearing loss. The principal questions to be answered concerning the possibility to determine which variant was involved and how influences on hearing "

Having identified the chromosome 7, the possible location of the gene altered the two groups of researchers have sequenced the gene in each "homologous genomic regions in man and mouse that are associated with hearing loss" and showed the presence of a mutation in the gene mir - 96.

Miguel Angel Moreno-Pelayo, author of the study and researcher at the Hospital Ramon y Cajal in Spain, said "We know a number of genes associated with deafness in humans and mice, but we discovered with surprise that this belongs to a new class of MicroRNA genes defined. No one had observed a mutation that can cause disease in a couple of MicroRNA sequence. This is the first MicroRNA gene associated with hearing loss and e 'is significant that the first to be associated with a hereditary condition. "

Experts recognize that the MicroRNA may bind to the active messengers in the generation of cell protein, effectively stopping the process and now have discovered that it is possible to analyze the role of mutation in mice. It seems the sensory hair cells in the mutant mice are affected by mir-96 gene, while mice carrying two copies of the gene mutant hair cells are deformed from birth and cells subjected to a degeneration in the early stages of life.

Morag Lewis of the Sanger Institute, who discovered the mutation, commented "The mutation, or variation of a single letter of genetic code from A to T in this tiny extension, is sufficient to cause a serious loss in mice" .

This mechanism also occurs in humans but, according to analysis of the two families used as a sample, the mutation does not happen ever in the same regions where the mouse, although affect neighboring regions, and always very important for the proper functioning of mir-96 .