De novo deletion removes a conserved motif in the C-terminus of ABCA4 and results in cone-rod dystrophy

: Mutations in the retina-specific ABC transporter ( ) gene are associated with different types of macular degeneration, including Stargardt disease, cone-rod dystrophy, and probably age-related macular degeneration. : Screening for mutations in the gene was performed using denaturing high-performance liquid chromatography and direct sequencing. : We describe the identification of a new de novo 44-bp deletion in an Italian patient affected by cone-rod dystrophy. The mutation, located in intron 48 of the gene, is predicted to cause exon 49 skipping, resulting in loss of the C-terminus of the ABCA4 protein. Interestingly, exon 49 also codes for a highly conserved VFVNFA motif, which has been demonstrated to be essential for the activity of , another gene of the ABC transporter family. The presence of CT repeats at the breakpoints might have facilitated the generation of the deletion through a slippage mispairing mechanism. : The new 6730–16del44 deletion is the first de novo mutation associated with cone-rod dystrophy and may contribute to a better understand-ing of the role of mutations in macular dystrophies.