GJB2 and deafness: For such recurrent variants, founder effects have been demonstrated in many deafness genes: for example, with regard to GJB2, it is reported that c.35delG, which is predominant throughout Europe, the Middle East, North Africa, North and South America and Australia; and c.235delC, which is commonly found in East Asians, are due to founder effects (see review; Tsukada et al. 2015).