Relatively mild blue cone monochromacy phenotype caused by various haplotypes in the L- and M-cone opsin genes.

Abstract

Purpose:

Blue cone monochromacy (BCM) is an X-linked retinopathy caused by mutations in the red and green cone opsin genes. The aim of this study was to establish the clinical, genetic, and electrophysiological characteristics of a specific form of BCM.

Methods:

Patients harboring mutations in the OPN1LW/OPN1MW genes underwent a full clinical examination, including ocular examination, color vision, full-field electroretinography, color fundus and autofluorescence photography, and optical coherence tomography. Genetic analysis was performed using whole-exome sequencing, duplex PCR, PCR/restriction fragment length polymorphism, and Sanger sequencing. IBM SPSS Statistics v. 21.0 was used for the data analysis.

Results:

Twenty-five patients harboring various haplotypes in exon 3 of the OPN1LW/OPN1MW genes were recruited. They showed a milder incomplete phenotype of BCM than the typical BCM control group. They presented significantly better visual acuity (logarithm of the minimum angle of resolution [logMAR] 0.48 ± 0.26 vs. 1.10 ± 0.54; p < 0.0001) and a highly myopic refraction (-7.81 ± 5.81 D vs. -4.78 ± 5.27 D; p = 0.0222) compared with the BCM control group. The study group had higher 30-Hz cone flicker responses (28.60 ± 15.02 µv; n = 24), whereas the BCM group had none (0.66 ± 2.12 µv; n = 21; p < 0.0001). The Lanthony 15-HUE desaturated test was variable for the exon 3 haplotype group, with a tendency toward the deutan-protan axis.

Conclusions:

The present study included genetic and clinical data from the largest cohort of patients with exon 3 haplotypes that were previously shown to cause missplicing of the OPN1LW and OPN1MW genes. Analysis of the clinical data revealed better best-corrected visual acuity, more severe myopia, and higher 30-Hz cone flicker responses in the patients with exon 3 haplotypes than in those with typical BCM.

• Authors: Samer Khateb, Aya Shemesh, Ashly Offenheim, Ruth Sheffer, Tamar Ben-Yosef, Itay Chowers, Rina Leibu, Britta Baumann, Bernd Wissinger, Susanne Kohl, Eyal Banin, Dror Sharon
• Journal: Molecular vision (Mol Vis) Vol. 28 Pg. 21-28 ( 2022) ISSN: 1090-0535 [Electronic] United States
• PMID: 35400991 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2022 Molecular Vision.

Chemical References

• Cone Opsins

Topics

• Color Vision Defects (genetics)
• Cone Opsins (genetics)
• Electroretinography
• Haplotypes
• Humans
• Myopia (genetics)
• Pedigree
• Phenotype