Mouse models have shown that photoreceptors degenerate and die when the syntaxin 3 gene is inactivated, the major retinal splice form of which is syntaxin 3B, while human syntaxin 3 mutations that impact syntaxin 3B have been linked to an early-onset severe retinal dystrophy in patients with syntaxin 3A-associated microvillus inclusion disease. This evidence concerns the gene STX3 and microvillus inclusion disease.