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. 2023 Jan 27;11(2):385.
doi: 10.3390/biomedicines11020385.

Clinical and Therapeutic Evaluation of the Ten Most Prevalent CRB1 Mutations

Bruna Lopes da Costa  1   2   3   4 , Masha Kolesnikova  2   3   5 , Sarah R Levi  2   3 , Thiago Cabral  4   6   7 , Stephen H Tsang  1   2   3   8   9 , Irene H Maumenee  2   3 , Peter M J Quinn  2   3
Affiliations

Clinical and Therapeutic Evaluation of the Ten Most Prevalent CRB1 Mutations

Bruna Lopes da Costa et al. Biomedicines. .

Abstract

Mutations in the Crumbs homolog 1 (CRB1) gene lead to severe inherited retinal dystrophies (IRDs), accounting for nearly 80,000 cases worldwide. To date, there is no therapeutic option for patients suffering from CRB1-IRDs. Therefore, it is of great interest to evaluate gene editing strategies capable of correcting CRB1 mutations. A retrospective chart review was conducted on ten patients demonstrating one or two of the top ten most prevalent CRB1 mutations and receiving care at Columbia University Irving Medical Center, New York, NY, USA. Patient phenotypes were consistent with previously published data for individual CRB1 mutations. To identify the optimal gene editing strategy for these ten mutations, base and prime editing designs were evaluated. For base editing, we adopted the use of a near-PAMless Cas9 (SpRY Cas9), whereas for prime editing, we evaluated the canonical NGG and NGA prime editors. We demonstrate that for the correction of c.2843G>A, p.(Cys948Tyr), the most prevalent CRB1 mutation, base editing has the potential to generate harmful bystanders. Prime editing, however, avoids these bystanders, highlighting its future potential to halt CRB1-mediated disease progression. Additional studies investigating prime editing for CRB1-IRDs are needed, as well as a thorough analysis of prime editing's application, efficiency, and safety in the retina.

Keywords: CRISPR; Crumbs homolog 1 (CRB1); Leber Congenital Amaurosis (LCA); base editing; inherited retinal disease (IRD); maculopathy; prime editing; retinitis pigmentosa.

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Conflict of interest statement

Stephen H. Tsang receives financial support from Abeona Therapeutics, Inc and Emendo. He is also the founder of Rejuvitas and is on the scientific and clinical advisory board for Nanoscope Therapeutics. Peter M.J. Quinn receives research support from Rejuvitas, Inc. Columbia University has filed patent applications related to this work for which Bruna Lopes da Costa, Stephen H. Tsang., and Peter M.J. Quinn are listed as inventors.

Figures

Figure 1
Figure 1
Color fundus imaging for nine patients with at least one confirmed mutation among the ten most prevalent mutations in CRB1. (A–E) Patients 1, 3, 4, 5, and 7, respectively, with ages ranging from 20 to 49 years old, demonstrated extensive intraretinal pigment migration 360-degrees throughout the periphery with relative para-arteriolar sparing. (F) Patient 6 presented with significant macular atrophy extending beyond the arcades with central pigmentary changes. There is no peripheral pigment migration. (G–I) Patients 2, 8, and 9, respectively, who are under the age of 10, demonstrated rare pigment migration scattered throughout the posterior pole and peripheral retina.
Figure 2
Figure 2
Short-wavelength autofluorescence (SW-AF) for three patients with at least one confirmed mutation in the top ten most prevalent variants of CRB1 and representative spectral domain optical coherence topography (SD-OCT) imaging of patients with two mutations in CRB1. (A,B) Two SW-AF images from patients 3 and 7, respectively, representative of typical SW-AF presentation in patients with confirmed CRB1 mutations. There is globally diminished autofluorescence with overlying heterogeneous pattern of hypoautofluorescence involving the posterior pole and peripheral retina. (C) SW-AF of patient 6 showing central atrophy in the macula extending nasally past the optic nerve, superiorly greater than inferiorly. (D) SD-OCT imaging from patient 2 representative of typical SD-OCT presentation in patients with confirmed CRB1 mutations. Retinal layers are poorly delaminated. There is foveal hypoplasia and increased retinal thickness.
Figure 3
Figure 3
Base editing designs for the six trasition variants—c.614T>C (A), c.1576C>T (B), c.2843G>A (C), c.2234C>T (D), c.2290C>T (E), c.3307G>A (F)—in the top 10 most frequent CRB1 mutations.
Figure 4
Figure 4
Prime editing design for the top 10 prevalent CRB1 mutations—c.614T>C (A), c.3307A>G (B), c.2843AG>A (C), c.613_619del (ATAGGAA)(D), c.2688T>A (E), c.2401A>T (F), c.2234C>T (G), c.2290C>T (H), c.1576C>T (I), and c.498_506del (AATTGATGG) (J).
See this image and copyright information in PMC

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