X-linked congenital stationary night blindness is a nonprogressive retinal disorder characterized by decreased visual acuity and loss of night vision. Bergen et al. (1995) stated that X-linked CSNB (CSNBX) is clinically heterogeneous with respect to the involvement of ... X-linked congenital stationary night blindness is a nonprogressive retinal disorder characterized by decreased visual acuity and loss of night vision. Bergen et al. (1995) stated that X-linked CSNB (CSNBX) is clinically heterogeneous with respect to the involvement of retinal rods and/or cones in the disease. The classic form of X-linked congenital stationary night blindness (CSNB1; 310500) is associated with myopia. All affected members of the family mapped by Bergen et al. (1996) to Xp21.1 had myopia and a fine horizontal nystagmus. None of them experienced deterioration, during an average follow-up of 5 years, of their visual acuity or ERG recordings. The 6 obligate carriers and 1 possible carrier had normal visual acuity, no myopia, and no abnormalities on ERG. The affected males, apart from night blindness as shown by the dark adaptation curves, had no clinical or electrophysiologic signs of retinitis pigmentosa.
Conducting mutation analysis in 13 families with the incomplete form of X-linked congenital stationary night blindness type 2, Strom et al. (1998) identified 9 different mutations in the CACNA1F gene in 10 families, including 3 nonsense and 1 ... Conducting mutation analysis in 13 families with the incomplete form of X-linked congenital stationary night blindness type 2, Strom et al. (1998) identified 9 different mutations in the CACNA1F gene in 10 families, including 3 nonsense and 1 frameshift mutation (see, e.g., 300110.0001-300110.0002). Similarly, by mutation analysis of the CACNA1F gene in 20 families with incomplete CSNB, Bech-Hansen et al. (1998) found 6 different mutations, all of which predicted premature protein truncation (see, e.g., 300110.0003-300110.0004). In 7 Japanese patients from 5 unrelated families with incomplete CSNB, Nakamura et al. (2001) identified 5 different mutations in the CACNA1F gene. Clinically, each patient had essentially normal fundi, mildly reduced corrected visual acuity, and slight myopia or hyperopia with astigmatism. Electrophysiologically, the mixed rod-cone ERG showed a negative configuration with recordable oscillatory potentials. The rod ERG was recordable but subnormal, and the cone and 30-Hz flicker ERGs were markedly depressed. Nakamura et al. (2001) concluded that in most Japanese patients with incomplete CSNB, the phenotype is caused by mutation in the CACNA1F gene.