CACNA2D4 and retinal degeneration: A 30 kb heterozygous deletion (including exon 19 to 26) in the CACNA2D4 gene with a homozygous deletion in C21orf2 was observed in a patient with retinal degeneration (RD) who clinically had a similar phenotype as an RD-patient with only homozygous C21orf2 mutation, suggesting the noninvolvement of CACNA2D4 in RD [47].