*7.1. LRIT3*

Recently, a dog model of recessively inherited CSNB has been identified due to a mutation in leucine-rich-repeat, immunoglobulin-like transmembrane-domain 3 gene (*LRIT3*). Mutations in *LRIT3* in humans causes a form of CSNB [139]. The ERG of the affected dogs shows a lack of ON-bipolar cell function with preservation of cone OFF-bipolar contributions [140–142]. There is currently debate about the positioning of the LRIT3 protein which had been described as being in the synaptic tips of the bipolar cells; however, a recent publication showed that it was presynaptic, being present in photoreceptors, but bridged the synapse to influence the positioning of post-synaptic glutamate signaling proteins [143]. The new availability of a large animal model may facilitate further investigations.
