Founder mutation in EYS Akio Oishi, University of Bonn 18 August 2015 I read with interest the article by Yoon et al. They are to be congratulated for demonstrating the genetic overview of Korean RP patients. I have one question regarding a mutation in EYS. They found c.4958_4959insA, p.S1653fs in two families and reported it as a novel mutation. Interestingly, c.4957dupA, p.S1653Kfs is a common mutation in Japan as shown in several studies. 1-3 Since the sequence from c.4951 to c.4960 of EYS is CTATCAAGTA, insertion of A in 4955_4956, 4956_4957, or 4957_4958 cannot be differentiated but 4958_4959insA is not identical. Are these mutations independent founder variants? If so, the position might be a hot spot in eastern Asian population. Alternatively, did the difference stem from the different reference sequence? I’m curious to see the result of Sanger sequencing. 1. Hosono K, Ishigami C, Takahashi M, et al. Two novel mutations in the EYS gene are possible major causes of autosomal recessive retinitis pigmentosa in the Japanese population. PLoS One 2012;7(2):e31036. 2. Iwanami M, Oshikawa M, Nishida T, et al. High prevalence of mutations in the EYS gene in Japanese patients with autosomal recessive retinitis pigmentosa. Invest Ophthalmol Vis Sci 2012;53(2):1033-40. 3. Oishi M, Oishi A, Gotoh N, et al. Comprehensive molecular diagnosis of a large cohort of Japanese retinitis pigmentosa and usher syndrome patients by next-generation sequencing. Invest Ophthalmol Vis Sci 2014;55(11):7369-75. Competing interests I do not have any competing interest.