Mutations in Cause Distinctive Retinal Dysfunction in Humans

CACNA2D4 (NM_172364) encodes the α2δ4 subunit of the photoreceptor voltage-gated calcium channels (Cav1.4), which modulate glutamate release from the photoreceptors to the bipolar cells.1 CACNA2D4 mutations have been associated with a rare recessive retinal cone dystrophy (RCD4, OMIM #610478),2 first described in 2 adult siblings with a homozygous truncating mutation in exon 25 of CACNA2D4: c.[2406C>A] (p.[Tyr802*]) associated with mildly reduced visual acuity (VA), photophobia, foveal pigment mottling, an electronegative scotopic electroretinogram (ERG) and markedly subnormal cone responses.