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Anti-deafness
gene found
Wednesday, 29 November 2000
Scientists have discovered an
anti-deafness gene, which appears to suppress the action of another gene
which would normally cause deafness, from birth.
The US and
Pakistani researchers say the modified gene could prove to be a more
general suppressor of certain types of genetically determined deafness, in
a letter to Nature
Genetics.
The discovery of the modifier gene came when the
team was mapping a new deafness gene.
More than half of severe
childhood deafness is genetically determined, and so far, about 6
defective genes have been identified.
Edward Wilcox of the National
Institute on Deafness and other Communication Disorders, and his
colleagues stumbled across the genetic variant in a study in a large
Pakistani family in which several members have severe hearing
loss.
They carried out a genome scan, which involves looking for a
correlation between genetic markers and the incidence of disease. They
homed in on a specific set of DNA markers on chromosome 4, but then
discovered that family members carrying two sets of these markers (one on
each copy chromosome 4) could hear perfectly well.
The researchers
said "this observation indicated either the existence of a modifier gene
suppressing the development [of the deafness gene] or that the gene was
located elsewhere."
They carried out another genome scan on the
hearing individuals and found that markers in a region on chromosome 1
correlated with hearing in those people. It appeared that a genetic
variant in this region 'counteracted' the chromosome-4 defect.
The
researchers say modified genes can act to suppress or enhance a mutant
phenotype. The one they have recorded can be classed as a suppressor of
the particular type of genetic deafness inherited in the Pakistani family
they studied.
Although the identities of the gene or genes in the
chromosome-4 and -1 regions have yet to be determined, the team reports
"it is possible [it] will prove to be a more general suppressor of a
specific class of mutant alleles of a variety of different
genes."
They believe an understanding of the underlying mechanism
of suppression awaits the identification of the genes
involved.
However, they said that analysis of the deafness gene and
the modifier gene "should provide new insights into the molecular
mechanisms of auditory function and facilitate the rational design of
therapies for hearing loss".
ABC science
on-line
More
Info?
News in
Science New gene research could spell the end for deafness
26/11/1999
News in
Science 2/02/99 Deafness curable, predicts bionic ear maker
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