Compoundheterozygous mutations are common causes of autosomal recessive inherited eye diseases.For example, biallelic heterozygous mutations of DRAM2 andTTLL5 lead to retinal dystrophies (El-Asrag et al., 2015; Sergouniotis et al., 2014), compound heterozygous mutationsof ATF6 are the basis of the cone dysfunction disorder achromatopsia(Kohl et al., 2015), andcompound heterozygous mutations in OTX2 and MAB21L2were reported to be a cause of A/M (Ragge etal., 2005; Rainger etal., 2014). The gene discussed is OTX2; the disease is achromatopsia.