title: Spectrum of GJB2 mutations in Turkey comprises both Caucasian and Oriental variants: roles of parental consanguinity and assortative mating.
abstract: Considerable differences exist for the spectrum of GJB2 mutations in different populations. Screening for the c.35delG mutation in 256 independent probands, 154 multiplex (familial) and 102 simplex (sporadic), coming from different regions of Turkey revealed 37 (14.5%) homozygotes. The allele frequency of c.35delG ranged from 5% to 53% in different cities. Parental consanguinity was noted in 34% of c.35delG homozygotes, yet it was 55% in c.35delG negatives (p=0.034). Further screening for GJB2 mutations in multiplex families demonstrated the presence of c.167delT and L90P mutations as well as a novel complex mutation, c.236_239delTGCAinsAGATCCG, in single alleles, leading to compound heterozygosity with c.35delG. The homozygous E120del mutation was found in another case. The V27I polymorphism was detected in five alleles, one of which was associated with the E114G change. Assortative mating was a significant factor predicting to detect biallelic mutations in the GJB2 gene. These results confirm the overwhelming majority of c.35delG in the Turkish deaf individuals as well as the presence of other changes detected in Caucasian and Asian populations.
authors.affiliation: Division of Pediatric Molecular Genetics, Ankara University School of Medicine, Ankara, Turkey. mtekin@medicine.ankara.edu.tr
authors.forename: Mustafa
authors.initials: M
authors.lastname: Tekin
authors.forename: Türker
authors.initials: T
authors.lastname: Duman
authors.forename: Gönül
authors.initials: G
authors.lastname: Boğoçlu
authors.forename: Armağan
authors.initials: A
authors.lastname: Incesulu
authors.forename: Elif
authors.initials: E
authors.lastname: Comak
authors.forename: Inci
authors.initials: I
authors.lastname: Ilhan
authors.forename: Nejat
authors.initials: N
authors.lastname: Akar
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003241:Consanguinity; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D005843:Geography; D034381:Hearing Loss / Q000208:ethnology / Q000235:genetics*; D006801:Humans; D008297:Male; D008393:Marriage; D009154:Mutation; D011110:Polymorphism, Genetic; D017384:Sequence Deletion; D014421:Turkey / Q000453:epidemiology; D044465:White People / Q000235:genetics
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26; D004247:DNA