Hearing loss is the most common inherited sensorial
deficiency in
humans; about 1 in 1000
children suffer from severe or profound
hearing loss at
birth.
Mutations in the GJB2
gene are the most common cause of prelingual, non-syndromic autosomal recessive
deafness in many
populations; the c.35delG
mutation is the most common in Caucasian
populations. The frequency of the c.35delG
mutation was estimated in two samples of deaf
patients from Santiago,
Chile. Unrelated non-syndromic sensorioneural deaf
patients were examined Group 1 consisted of 47 unrelated individuals with
neurosensory deafness referred to the Chilean
Cochlear Implant Program; Group 2 included 66
school children with
prelingual deafness attending
special education institutions for deaf people. Individuals with profound to moderate isolated neurosensory
hearing loss with unknown
etiology were included. The presence of the c.35delG
mutation was evaluated by the
allele-specific
polymerase chain reaction method (
PCR), and in some cases it was confirmed by direct
DNA sequencing of the
coding region of the GJB2
gene. Deaf
relatives were present in 20.3% of the cases. We found 19.5% (22/113)
patients with the c.35delG
mutation, 6 of them homozygous; these rates are
similar to frequencies found in other Latin American countries.