Novel and Previously Known Mutations of the KCNV2 Gene Cause Various Variants of the Clinical Course of Cone Dystrophy with Supernormal Rod Response in Children
<p>Fundus photos, fundus autofluorescence (FAF) and optical coherence tomography (OCT) of the first case in both eyes. (<b>a</b>,<b>b</b>) Fundusoscopy shows that the optic disc is pink, with clear contours and normal retinal vessels; (<b>c</b>,<b>d</b>) FAF shows an enlarged macular reflex that is somewhat darkened and blurred; (<b>e</b>,<b>f</b>) OCT shows the perspicuous thinning of the retina in all layers, and is more pronounced in the foveal zone.</p> "> Figure 2
<p>Fundus photos, fundus autofluorescence (FAF) and optical coherence tomography (OCT) of the second case in both eyes. (<b>a</b>,<b>b</b>) The last fundoscopy reveals a standard optic disc and retinal vessel morphology with macular and foveal reflexes absent. (<b>c</b>,<b>d</b>) FAF presents symmetrical abnormal spots of hypoautofluorescence surrounded by a ring of hyperautofluorescence; (<b>e</b>,<b>f</b>) OCT shows a slight decrease in the average thickness of the neuroepithelium with the absence of the myoid and ellipsoid zones of the fovea.</p> "> Figure 3
<p>Full−field ERG in the first and second cases is comparable with a normal ERG. The first patient ERG was close to supernormal. The scotopic rod–cone response revealed an increase in the latency of the a− and b− waves. ERG is subnormal; the amplitudes of a–b waves are reduced. The flicker response amplitude was found to be reduced compared to the norm. The second patient’s ERG revealed a decrease in the amplitude and an increase in the latent period of the b-wave in both cone and rod responses. The amplitude of the flicker ERG response decreased compared to the age norm.</p> "> Figure 4
<p>Direct sequencing of the <span class="html-italic">KCNV2</span> gene in the first and second patients. The first patient revealed a de novo mutation, c.1109dup, and another at position c.859C>T, forming a complex heterozygous mutation in the proband. The second patient revealed a complex heterozygous mutation, containing c.754A>T and c.775G>A substitutions. Substitutions are marked with asterisks.</p> "> Figure 5
<p>Schematic diagram of the <span class="html-italic">KCVN2</span> potassium channel subunit. The structure of the alpha subunit of the potential-dependent potassium channel is represented by N-terminal A- and B-boxes (NABs), transmembrane domains (S1–S6), extracellular domains, and a P loop motif between S5 and S6. The approximate location of mutations (black dots) related to the patients is shown in the diagrammatic structure in blue and red for the first and second cases, respectively.</p> ">
Abstract
:1. Introduction
2. Materials and Methods
2.1. Clinical Assessment
2.2. Electrophysiological Assessment
2.3. Molecular Genetics
3. Results
3.1. Subjects and Clinical Findings
3.2. Molecular Genetics
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Alsalloum, A.; Mosin, I.; Shefer, K.; Mingaleva, N.; Kim, A.; Feoktistova, S.; Malyugin, B.; Boiko, E.; Sultanov, S.; Mityaeva, O.; et al. Novel and Previously Known Mutations of the KCNV2 Gene Cause Various Variants of the Clinical Course of Cone Dystrophy with Supernormal Rod Response in Children. J. Clin. Med. 2024, 13, 4592. https://doi.org/10.3390/jcm13164592
Alsalloum A, Mosin I, Shefer K, Mingaleva N, Kim A, Feoktistova S, Malyugin B, Boiko E, Sultanov S, Mityaeva O, et al. Novel and Previously Known Mutations of the KCNV2 Gene Cause Various Variants of the Clinical Course of Cone Dystrophy with Supernormal Rod Response in Children. Journal of Clinical Medicine. 2024; 13(16):4592. https://doi.org/10.3390/jcm13164592
Chicago/Turabian StyleAlsalloum, Almaqdad, Ilya Mosin, Kristina Shefer, Natalia Mingaleva, Alexander Kim, Sofya Feoktistova, Boris Malyugin, Ernest Boiko, Shamil Sultanov, Olga Mityaeva, and et al. 2024. "Novel and Previously Known Mutations of the KCNV2 Gene Cause Various Variants of the Clinical Course of Cone Dystrophy with Supernormal Rod Response in Children" Journal of Clinical Medicine 13, no. 16: 4592. https://doi.org/10.3390/jcm13164592