Related Experiment Video
Updated: Aug 8, 2026
Mouse Eye Enucleation for Remote High-throughput Phenotyping
Published on: November 19, 2011
Clinical variability among patients with incomplete X-linked congenital stationary night blindness and a founder
K M Boycott1, W G Pearce, N T Bech-Hansen
1Department of Medical Genetics, Faculty of Medicine, University of Calgary, Alta.
Background:
Incomplete X-linked congenital stationary night blindness (CSNB) is a clinically variable condition that has been shown to be caused by mutations in the calcium-channel CACNA1F gene. We assessed the clinical variability in the expression of the incomplete CSNB phenotype in a subgroup of patients of Mennonite ancestry with the same founder mutation.
Methods:
Sixty-six male patients from 15 families were identified with a common mutation in exon 27 of CACNA1F (L1056insC). Clinical variability in night blindness, reduced visual acuity, myopia, nystagmus and strabismus was examined.
Results:
At least one of the major features of CSNB (night blindness, myopia and nystagmus) was absent in 72% of the patients. All the examined features varied widely, both between and within families.
Interpretation:
Although the patients shared a common CACNA1F mutation, there was considerable variability in the clinical expression of the incomplete CSNB phenotype. These findings suggest the presence of other genetic factors modifying the phenotype of this disorder.
Related Concept Videos
01:11Genetic Lingo
02:26Comparing Copy Number Variations and SNPs
Copy number variations or CNVs are the structural variations that cover more than 1kb of DNA sequence. The single nucleotide polymorphism (SNP), on the other hand, is a single nucleotide change or a point mutation that is found in more than 1%...
01:22Photoreceptors and Visual Pathways