Background: Mutations at Gly-90 in rhodopsin cause two different phenotypes: retinitis pigmentosa and congenital night blindness. Results: G90V retinitis pigmentosa mutant shows constitutive activity and very low thermal stability in the dark state. Conclusion: Low conformational stability can trigger retinitis pigmentosa associated with rhodopsin mutations. Significance: Retinoids can help to stabilize the conformation of retinitis pigmentosa mutants.