C.35delG/ GJB2 and del(GJB6-D13S1830) mutations in Croatians with prelingual non-syndromic hearing impairment

Igor Medica¹^,2 , Gorazd Rudolf¹ , Manuela Balaban¹^,2 and Borut Peterlin¹

¹Division of Medical Genetics, Department of Obstetrics and Gynaecology, University Medical Centre Ljubljana, Slovenia, Slajmerjeva 3 1000 Ljubljana, Slovenia

²Outpatient Paediatric Clinic Pula, Croatia, Istarska 13 52100 Pula, Croatia

author email corresponding author email

BMC Ear, Nose and Throat Disorders 2005, 5:11doi:10.1186/1472-6815-5-11


Published:	8 December 2005

Abstract

Background

C.35delG/GJB2 mutation is the most frequent genetic cause of deafness in Caucasians. Another frequent mutation in some Caucasian populations is del(GJB6-D13S1830). Both GJB2 and GJB6 genes belong to the same DFNB1 locus and when the two mutations are found in combination in a hearing-impaired person, a digenic pattern of inheritance is suggested.

Methods

We examined 63 Croatian subjects (25 familial and 38 sporadic cases) with prelingual non-syndromic hearing impairment by polymerase chain reaction for the presence of the c.35delG/GJB2 and the del(GJB6-D13S1830) mutations.

Results

Of the 63 unrelated hearing-impaired subjects, the mutation c.35delG/GJB2 was found in 21 subjects (33.3%). In 5 of them the mutation was found in the heterozygous state, all of them being compound heterozygotes, as sequencing revealed a second mutation within the coding region of the gene in 3 subjects, and a splice site mutation in 2 subjects. The del(GJB6-D13S1830) mutation was not found in the investigated hearing-impaired Croatian subjects.

Conclusion

Our results contribute to the knowledge of geographic distribution and population genetics of the GJB2 and GJB6 mutations in the Europeans.