“…So far, 43 disease‐causing mutations in RP1 have been identified of which most were found in the last exon, leading to a premature stop codon and are predicted to form a truncated protein (Table 1). The p.Arg677X has been described as the most commonly reported mutation [Baum et al, 2001; Berson et al, 2001; Bowne et al, 1999; Chiang et al, 2006; Gamundi et al, 2006; Guillonneau et al, 1999; Jacobson et al, 2000; Payne et al, 2000; Pierce et al, 1999; Roberts et al, 2006; Schwartz et al, 2003; Sohocki et al, 2001; Sullivan et al, 1999, 2006; Wang et al, 2005; Xiaoli et al, 2002; Ziviello et al, 2005]. Detailed phenotype–genotype correlation of patients with this mutation revealed incomplete penetrance and high variability of disease expression of adRP, suggesting modifiers to be involved [Jacobson et al, 2000].…”