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Cortinhal T, Santos C, Vaz-Pereira S, Marta A, Duarte L, Miranda V, Costa J, Sousa AB, Peter VG, Kaminska K, Rivolta C, Carvalho AL, Saraiva J, Soares CA, Silva R, Murta J, Santos LC, Marques JP. Genetic profile of syndromic retinitis pigmentosa in Portugal. Graefes Arch Clin Exp Ophthalmol 2024; 262:1883-1897. [PMID: 38189974 PMCID: PMC11106148 DOI: 10.1007/s00417-023-06360-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 12/11/2023] [Accepted: 12/28/2023] [Indexed: 01/09/2024] Open
Abstract
PURPOSE Retinitis pigmentosa (RP) comprises a genetically and clinically heterogeneous group of inherited retinal degenerations, where 20-30% of patients exhibit extra-ocular manifestations (syndromic RP). Understanding the genetic profile of RP has important implications for disease prognosis and genetic counseling. This study aimed to characterize the genetic profile of syndromic RP in Portugal. METHODS Multicenter, retrospective cohort study. Six Portuguese healthcare providers identified patients with a clinical diagnosis of syndromic RP and available genetic testing results. All patients had been previously subjected to a detailed ophthalmologic examination and clinically oriented genetic testing. Genetic variants were classified according to the American College of Medical Genetics and Genomics; only likely pathogenic or pathogenic variants were considered relevant for disease etiology. RESULTS One hundred and twenty-two patients (53.3% males) from 100 families were included. Usher syndrome was the most frequent diagnosis (62.0%), followed by Bardet-Biedl (19.0%) and Senior-Løken syndromes (7.0%). Deleterious variants were identified in 86/100 families for a diagnostic yield of 86.0% (87.1% for Usher and 94.7% for Bardet-Biedl). A total of 81 genetic variants were identified in 25 different genes, 22 of which are novel. USH2A and MYO7A were responsible for most type II and type I Usher syndrome cases, respectively. BBS1 variants were the cause of Bardet-Biedl syndrome in 52.6% of families. Best-corrected visual acuity (BCVA) records were available at baseline and last visit for 99 patients (198 eyes), with a median follow-up of 62.0 months. The mean BCVA was 56.5 ETDRS letters at baseline (Snellen equivalent ~ 20/80), declining to 44.9 ETDRS letters (Snellen equivalent ~ 20/125) at the last available follow-up (p < 0.001). CONCLUSION This is the first multicenter study depicting the genetic profile of syndromic RP in Portugal, thus contributing toward a better understanding of this heterogeneous disease group. Usher and Bardet-Biedl syndromes were found to be the most common types of syndromic RP in this large Portuguese cohort. A high diagnostic yield was obtained, highlighting current genetic testing capabilities in providing a molecular diagnosis to most affected individuals. This has major implications in determining disease-related prognosis and providing targeted genetic counseling for syndromic RP patients in Portugal.
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Affiliation(s)
- Telmo Cortinhal
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Cristina Santos
- Instituto de Oftalmologia Dr. Gama Pinto (IOGP), Lisboa, Portugal
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Sara Vaz-Pereira
- Department of Ophthalmology, Centro Hospitalar Universitário de Lisboa Norte (CHULN), Lisboa, Portugal
- Department of Ophthalmology, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Ana Marta
- Department of Ophthalmology, Centro Hospitalar e Universitário de Santo António (CHUdSA), Porto, Portugal
- Instituto Ciências Biomédicas Abel Salazar (ICBAS), Porto, Portugal
| | - Lilianne Duarte
- Department of Ophthalmology, Centro Hospitalar de Entre Douro e Vouga (CHEDV), Santa Maria da Feira, Portugal
| | - Vitor Miranda
- Department of Ophthalmology, Centro Hospitalar de Entre Douro e Vouga (CHEDV), Santa Maria da Feira, Portugal
| | - José Costa
- Department of Ophthalmology, Hospital de Braga (HB), Braga, Portugal
| | - Ana Berta Sousa
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Lisboa Norte (CHULN), Lisboa, Portugal
| | - Virginie G Peter
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland
- Department of Ophthalmology, University of Basel, 4031, Basel, Switzerland
- Department of Ophthalmology, Inselspital, Bern University Hospital, 3010, Bern, Switzerland
| | - Karolina Kaminska
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland
- Department of Ophthalmology, University of Basel, 4031, Basel, Switzerland
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland
- Department of Ophthalmology, University of Basel, 4031, Basel, Switzerland
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, United Kingdom
| | - Ana Luísa Carvalho
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Jorge Saraiva
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Célia Azevedo Soares
- Medical Genetics Department, Centro de Genética Médica Jacinto Magalhães, Centro Hospitalar e Universitário do Porto (CHUP), Porto, Portugal
- Unit for Multidisciplinary Research in Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- Medical Science Department, Universidade de Aveiro, Aveiro, Portugal
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Rufino Silva
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Joaquim Murta
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | | | - João Pedro Marques
- Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal.
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