Statistical study of 35delG mutation of GJB2 gene: a meta-analysis of carrier frequency.

GJB2 mutations are major causes of autosomal recessive nonsyndromic hearing loss (ARNSHL) in many populations. However, a few mutations have an ethnic-specific background. We performed a review by means of a meta-analysis to evaluate the influence of the 35delG on ARNSHL. A PubMed, InterScience, British Library Direct, and Sciencedirect search using keywords '35delG', 'GJB2' and 'Connexin 26' associated with 'carrier frequency' was carried out to include all papers from February 1998 to February 2008. 35delG carrier frequencies in 23187 random controls were analysed and categorized, corresponding with geographical boundaries, from all over the world. Mean carrier frequencies of 35delG mutation were found to be 1.89, 1.52, 0.64, 1, and 0.64 for European, American, Asian, Ocean, and African populations, respectively. We found that the average 35delG carrier frequency is highest in southern Europe and lowest in eastern Asia. The south-to-north European gradient in the carrier frequency of 35delG was confirmed and also a west-to-east Asian gradient is suggested. This study highlights the importance of establishing prevalence, based on the local population for screening and diagnostic programs of live births.