Mitfmi/+ as a new mouse model of cone dystrophy

Purpose: Mutations in the Mitf gene can lead to hypopigmentation, microphthalmia, retinal degeneration, deafness and blindness1. We have previously shown that RPE function and structure is affected in mice with various mutations in the Mitf gene, which is expressed specifically in the RPE, resulting in some cases in retinal degeneration2. The current study is the first of its kind to analyse visual and retinal function in Mitfmi/+ mice. Methods: Mitfmi/+ and C5BL/6 J (as control) mice were used in this study. All mice were 1‐ and 3‐months old. Electroretinography (ERG) was performed under both dark‐ and light‐adapted conditions, along with fundus photography from anaesthetised mice. The ERG dark‐adapted a‐, b‐ and c‐waves were analysed. Light‐adapted b‐wave amplitude was analysed. Fundus photography was performed to visualize and compare fundus images from wild type and Mitfmi/+ mice. Results: Light‐adapted a‐wave amplitude was significant lower in 3‐month‐old mutants (7.34 ± 1.34 μV, 6.72 ± 1.19 μV, 8.58 ± 1.03 μV; p