A Novel Splice-Site Variant in CACNA1F Causes a Phenotype Synonymous with à land Island Eye Disease and Incomplete Congenital Stationary Night Blindness.

BACKGROUND: CACNA1F-related disorders encompass progressive and non-progressive disorders, including à land island eye disease and incomplete congenital stationary night blindness. These two X-linked disorders are characterized by nystagmus, color vision defect, myopia, and electroretinography (ERG) abnormalities. Ocular hypopigmentation and iris transillumination are reported only in patients with à land island eye disease. Around 260 variants were reported to be associated with these two non-progressive disorders, with 19 specific to à land island eye disease and 14 associated with both à land island eye disease and incomplete congenital stationary night blindness. CACNA1F variants spread on the gene and further analysis are needed to reveal phenotype-genotype correlation. CASE REPORT: A complete ocular exam and genetic testing were performed on a 13-year-old boy. A novel splice-site variant, c.4294-11C>G in intron 36 in CACNA1F, was identified at hemizygous state in the patient and at heterozygous state in his asymptomatic mother and explained the phenotype synonymous with à land island eye disease and incomplete congenital stationary night blindness observed in the patient. CONCLUSION: We present a novel variant in the CACNA1F gene causing phenotypic and electrophysiologic findings indistinguishable from those of AIED/CSNB2A disease. This finding further expands the mutational spectrum and our knowledge of CACNA1F-related disease.