Purpose: To describe the genetic and clinical spectrum of GUCY2D-associated retinopathies and to accurately establish their prevalence in a large cohort of patients.
Design: Retrospective case series.
Methods: Institutional study of 47 patients from 27 unrelated families with retinal dystrophies carrying disease-causing GUCY2D variants from the Fundación Jiménez Díaz hospital dataset of 8000 patients. Patients underwent ophthalmological examination and molecular testing by Sanger or exome sequencing approaches. Statistical and principal component analyses were performed to determine genotype-phenotype correlations.
Results: Four clinically different associated phenotypes were identified: 66.7% of families with cone/cone-rod dystrophy, 22.2% with Leber congenital amaurosis, 7.4% with early-onset retinitis pigmentosa, and 3.7% with congenital night blindness. Twenty-three disease-causing GUCY2D variants were identified, including 6 novel variants. Biallelic variants accounted for 28% of patients, whereas most carried dominant alleles associated with cone/cone-rod dystrophy. The disease onset had statistically significant differences according to the functional variant effect. Patients carrying GUCY2D variants were projected into 3 subgroups by allelic combination, disease onset, and presence of nystagmus or night blindness. In contrast to patients with the most severe phenotype of Leber congenital amaurosis, 7 patients with biallelic GUCY2D had a later and milder rod form with night blindness in infancy as the first symptom.
Conclusions: This study represents the largest GUCY2D cohort in which 4 distinctly different phenotypes were identified, including rare intermediate presentations of rod-dominated retinopathies. We established that GUCY2D is linked to about 1% of approximately 3000 molecularly characterized families of our cohort. All of these findings are critical for defining cohorts for inclusion in future clinical trials.
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http://dx.doi.org/10.1016/j.ajo.2023.05.015 | DOI Listing |
Indian J Ophthalmol
December 2024
Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Anant Bajaj Retina Institute, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, Telangana, India.
Purpose: To assess the clinical phenotypes and genetic mutations in patients with Leber congenital amaurosis (LCA) from a tertiary eye care center in India.
Design: Retrospective observational study.
Methods: The study includes patients with a clinical diagnosis of LCA who underwent genetic testing from January 2016 to December 2021.
Biochemistry
September 2024
Department of Neuroscience, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg ,Germany.
Phototransduction in vertebrate photoreceptor cells is controlled by Ca-dependent feedback loops involving the membrane-bound guanylate cyclase GC-E that synthesizes the second messenger guanosine-3',5'-cyclic monophosphate. Intracellular Ca-sensor proteins named guanylate cyclase-activating proteins (GCAPs) regulate the activity of GC-E by switching from a Ca-bound inhibiting state to a Ca-free/Mg-bound activating state. The gene encodes for human GC-E, and mutations in are often associated with an imbalance of Ca and cGMP homeostasis causing retinal disorders.
View Article and Find Full Text PDFAm J Ophthalmol Case Rep
December 2024
Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA.
Purpose: Cone-rod dystrophies (CORD) are inherited retinal dystrophies characterized by primary cone degeneration with secondary rod involvement. We report two patients from the same family with a dominant variant in the guanylate cyclase 2D () gene with different phenotypes in the electroretinogram (ERG).
Observations: A 21-year-old lady (Patient 1) was referred due to experiencing blurry vision and color vision impairment.
Mol Syndromol
June 2024
Department of Medical Genetics, Konya City Hospital, Konya, Turkey.
Introduction: Inherited retinal dystrophies (IRDs) associated with more than 300 genes are a clinically and genetically heterogeneous group of retinal diseases. This study aimed to identify causative gene variants and molecular basis of Turkish patients with IRD.
Methods: Whole-exome sequencing was performed in 28 unrelated patients.
Graefes Arch Clin Exp Ophthalmol
September 2024
Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, Beijing, 100045, China.
Purpose: Leber congenital amaurosis (LCA) is a group of early-onset retinal degenerative disorders, resulting in blindness in children. This study aimed to describe the clinical and genetic characteristics of a cohort of patients with LCA and to investigate the retinal vascular characteristics in LCA patients.
Methods: Fifty-two children with LCA were included in the study.
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