@entity2319 resulting from mutations in the XXXX ( @entity3492 ) gene in Brazilian @entity1 .

@entity1 @entity3492 @entity693 @entity2319 @entity281 @entity519 @entity1274 @entity4701 @entity2462 @entity393
@entity2319 occurs in approximately 1 in 1000 live births. In developed countries about 60% of @entity393 is genetic. However, in Brazil most cases of @entity393 are due to environmental factors, such as @entity281 (mainly @entity2462 ), perinatal @entity519 , @entity693 . Recently, it has been demonstrated that the @entity3492 gene is a major gene underlying congenital @entity1274 . Mutations in this gene cause 10-20% of all genetic @entity393 . One specific mutation, @entity4701 , accounts for the majority of mutant alleles. The extent of the @entity393 varies from mild/moderate to profound, even within the @entity1 homozygous for the common @entity4701 mutation. There may also be progression with age. Mutation analysis in the @entity3492 gene was performed on 36 families (group A) presenting with at least one individual with @entity2319 ( @entity2319 ). An unselected series of 26 deaf individuals referred by other services where the environmental factors were not completely excluded was also part of the study (group B). Mutations in the @entity3492 gene were found in 22% (eight @entity1 ) of the families tested in group A, and 11.5% (three @entity1 ) of individuals within group B. This finding should facilitate diagnosis of @entity2319 and allow early treatment of the affected subjects.
