Prevalence of GJB2 mutations in prelingual deafness in the Greek population.
OBJECTIVE
Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) have been shown as a major contributor to prelingual, sensorineural, nonsyndromic, recessive deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations. The aim of our study was to determine the prevalence and spectrum of GJB2 mutations in prelingual deafness in the Greek population.


METHODS
In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific polymerase chain reaction (PCR) for the detection of the 35delG mutation. Patients heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene.


RESULTS
The 35delG mutation was found in 42.2% of the chromosomes in 45 familial cases of prelingual, nonsyndromic deafness (18 homozygotes and 2 heterozygotes) and in 30.6% of the chromosomes in 165 sporadic cases (45 homozygotes and 11 heterozygotes). Direct genomic sequencing in heterozygous patients revealed the L90P (2 alleles), W24X (2 alleles), R184P (2 alleles), and 291insA (1 allele) mutations.


CONCLUSIONS
Mutations in the GJB2 gene are responsible for about one third of prelingual, sensorineural, nonsyndromic deafness in the Greek population, and allele-specific PCR is an easy screening method for the common 35delG mutation.
Pampanos
Andreas
A
Department of Genetics, Institute of Child Health, Aghia Sophia Children's Hospital, GR-11527 Athens, Greece.
Economides
John
J
Iliadou
Vassiliki
V
Neou
Polyxeni
P
Leotsakos
Paulos
P
Voyiatzis
Nikolaos
N
Eleftheriades
Nikolaos
N
Tsakanikos
Michael
M
Antoniadi
Thalia
T
Hatzaki
Angeliki
A
Konstantopoulou
Irene
I
Yannoukakos
Drakoulis
D
Gronskov
Karen
K
Brondum-Nielsen
Karen
K
Grigoriadou
Maria
M
Gyftodimou
Jolanda
J
Iliades
Theophilos
T
Skevas
Antonios
A
Petersen
Michael B
MB
D001483:Base Sequence; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005820:Genetic Testing; D005838:Genotype; D006115:Greece / Q000453:epidemiology; D006319:Hearing Loss, Sensorineural / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011159:Population Surveillance; D015995:Prevalence
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26