Purpose: To describe a French family with the incomplete type of X-linked congenital stationary night blindness (CSNB2) associated with a novel mutation in the retina-specific calcium channel alpha(1) subunit gene (CACNA1F).
Design: Interventional case report.
Methods: Two family members with a history of nonprogressive night blindness and subnormal visual acuity were clinically examined and the genotype determined by molecular genetic analysis.
Result: Both patients had clinical manifestations characteristic of CSNB2. Electrophysiologically, we found a predominant reduction of the ERG B-wave in the maximal response. Both rod and cone function were subnormal, with the latter tending to be more attenuated. We identified a C deletion at nucleotide position 4548, resulting in a frameshift with a predicted premature termination at codon 1524.
Conclusions: The clinical and genetic study of a novel mutation in the CACNA1F gene adds further support to the contention that CSNB2 represents a genetically distinct retinal disorder of a calcium channel.