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Weisschuh N, Stingl K, Audo I, Biskup S, Bocquet B, Branham K, Burstedt MS, De Baere E, De Vries MJ, Golovleva I, Green A, Heckenlively J, Leroy BP, Meunier I, Traboulsi E, Wissinger B, Kohl S. Mutations in the gene PDE6C encoding the catalytic subunit of the cone photoreceptor phosphodiesterase in patients with achromatopsia. Hum Mutat 2018; 39:1366-1371. [PMID: 30080950 DOI: 10.1002/humu.23606] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/24/2018] [Accepted: 08/02/2018] [Indexed: 12/22/2022]
Abstract
Biallelic PDE6C mutations are a known cause for rod monochromacy, better known as autosomal recessive achromatopsia (ACHM), and early-onset cone photoreceptor dysfunction. PDE6C encodes the catalytic α'-subunit of the cone photoreceptor phosphodiesterase, thereby constituting an essential part of the phototransduction cascade. Here, we present the results of a study comprising 176 genetically preselected patients who remained unsolved after Sanger sequencing of the most frequent genes accounting for ACHM, and were subsequently screened for exonic and splice site variants in PDE6C applying a targeted next generation sequencing approach. We were able to identify potentially pathogenic biallelic variants in 15 index cases. The mutation spectrum comprises 18 different alleles, 15 of which are novel. Our study significantly contributes to the mutation spectrum of PDE6C and allows for a realistic estimate of the prevalence of PDE6C mutations in ACHM since our entire ACHM cohort comprises 1,074 independent families.
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Affiliation(s)
- Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Tuebingen, Tuebingen, Germany
| | - Katarina Stingl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Tuebingen, Tuebingen, Germany
| | - Isabelle Audo
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France
| | - Saskia Biskup
- CeGaT GmbH and Praxis fuer Humangenetik Tuebingen, Tuebingen, Germany
| | - Béatrice Bocquet
- Institute for Neurosciences of Montpellier INSERM U1051, University of Montpellier, Montpellier, France.,National Center for Rare Genetic Retinal Dystrophies, Hopital Gui de Chauliac, Montpellier, France
| | - Kari Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Marie S Burstedt
- Department of Clinical Sciences/Ophthalmology, University of Umea, Umea, Sweden
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Meindert J De Vries
- Department of Ophthalmology, Childrens' Hospital Queen Fabiola (Huderf), Brussels, Belgium
| | - Irina Golovleva
- Department of Medical Biosciences/Medical and Clinical Genetics, University of Umea, Umea, Sweden
| | - Andrew Green
- Department of Clinical Genetics, Our Lady's Hospital, Crumlin, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - John Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Bart P Leroy
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.,Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology & Center for Cellular & Molecular Therapy, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Ophthalmology, Ghent University Hospital & Ghent University, Ghent, Belgium
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier INSERM U1051, University of Montpellier, Montpellier, France.,National Center for Rare Genetic Retinal Dystrophies, Hopital Gui de Chauliac, Montpellier, France
| | | | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Tuebingen, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Tuebingen, Tuebingen, Germany
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Mayer AK, Van Cauwenbergh C, Rother C, Baumann B, Reuter P, De Baere E, Wissinger B, Kohl S. CNGB3 mutation spectrum including copy number variations in 552 achromatopsia patients. Hum Mutat 2017; 38:1579-1591. [PMID: 28795510 DOI: 10.1002/humu.23311] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/25/2017] [Accepted: 08/04/2017] [Indexed: 02/03/2023]
Abstract
Achromatopsia is a rare autosomal recessive cone disorder characterized by color vision defects, photophobia, nystagmus, and severely reduced visual acuity. The disease is caused by mutations in genes encoding crucial components of the cone phototransduction cascade (CNGA3, CNGB3, GNAT2, PDE6C, and PDE6H) or in ATF6, involved in the unfolded protein response. CNGB3 encoding the beta subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is the major achromatopsia gene. Here, we present a comprehensive spectrum of CNGB3 mutations and their prevalence in a cohort of 1074 independent families clinically diagnosed with achromatopsia. Of these, 485 (45.2%) carried mutations in CNGB3. We identified a total of 98 different potentially disease-causing CNGB3 variants, 58 of which are novel. About 10% of patients with CNGB3 mutations only harbored a single heterozygous variant. Therefore, we performed quantitative real-time PCR in 43 of such single heterozygotes in search of the missing allele, followed by microarray-based comparative genomic hybridization and breakpoint mapping. We discovered nine different heterozygous copy number variations encompassing one to 10 consecutive exons in 16 unrelated patients. Moreover, one additional patient with a homozygous CNGB3 deletion encompassing exons 4-18 was identified, highlighting the importance of CNV analysis for this gene.
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Affiliation(s)
- Anja K Mayer
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
| | - Caroline Van Cauwenbergh
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Christine Rother
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
| | - Britta Baumann
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
| | - Peggy Reuter
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
| | - Elfride De Baere
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany
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