GNAT1 encodes the α-subunit of rod transducin, a critical G protein that functions as a signal transducer downstream of rhodopsin (RHO) in rod photoreceptors 1. Upon light activation, RHO promotes GDP release and GTP binding to GNAT1, enabling its interaction with downstream effector proteins including cGMP-phosphodiesterase to modulate cyclic nucleotide levels and elicit electrical changes in photoreceptor cells 2. This phototransduction cascade represents the first neuronal step in vision perception 1. Pathogenic variants in GNAT1 cause inherited retinal diseases, primarily congenital stationary night blindness (CSNB). Autosomal dominant missense variants like p.G38D cause Nougaret-type CSNB with characteristic electronegative electroretinograms and delayed, broadened a-waves 3. Autosomal recessive GNAT1 mutations present with early-onset night blindness; homozygous truncating mutations can cause late-onset retinitis pigmentosa with progressive retinal degeneration in addition to lifelong night blindness 4. In-frame deletions produce similar rod-specific dysfunction with reduced scotopic responses 5. Clinically, GNAT1-associated retinal disease manifests as nonprogressive night blindness with electroretinographic evidence of rod photoreceptor dysfunction, often accompanied by nystagmus and myopia 2. The severity depends on mutation type and inheritance pattern, with recessive complete loss-of-function variants causing the most severe phenotypes.