CNGB1-related rod-cone dystrophy: a mutation review and update.

CNGB1 (Cyclic nucleotide-gated channel β 1) encodes the 240-kDa β subunit of the rod photoreceptor cyclic nucleotide-gated ion channel. Disease-causing sequence variants in CNGB1 lead to autosomal recessive rod-cone dystrophy/retinitis pigmentosa (RP). We herein present a comprehensive review and analysis of all previously reported CNGB1 sequence variants, and add 22 novel variants, thereby enlarging the spectrum to 84 variants in total, including 24 missense variants (two of which may also affect splicing), 21 nonsense, 19 splicing defects (7 at non-canonical positions), 10 small deletions, 1 small insertion, 1 small insertion-deletion, 7 small duplications and 1 gross deletion. According to the ACMG classification criteria, 59 variants were considered pathogenic or likely pathogenic and 25 were variants of uncertain significance. In addition, we provide further phenotypic data from 34 CNGB1-related RP cases which, overall, are in line with previous findings suggesting that this form of RP has a long-term retention of useful central vision despite the early onset of night blindness, which is valuable for patient counseling, but also has implications for it being considered a priority target for gene therapy trials. This article is protected by copyright. All rights reserved.