1
|
Sanlialp A, Escher P, Schaller A, Todorova M. Clinical Heterogeneity in Two Siblings Harbouring a Heterozygous PRPH2 Pathogenic Variant. Klin Monbl Augenheilkd 2023; 240:536-543. [PMID: 37164409 DOI: 10.1055/a-2034-6250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
PURPOSE The aim of the study was to describe the clinical and genetic correlation of a c.469 G>A p.(Asp157Asn) heterozygous pathogenic variant in PRPH2 in two siblings of Italian origin. PATIENTS AND METHODS Both patients underwent ophthalmic examination, electrophysiological testing, autofluorescence imaging, and optical coherence tomography (OCT). Screening for pathogenic variants of the obtained DNA from the family members was carried out. RESULTS The 52-year-old (♀, index patient) and 50-year-old (♂) siblings had BCVA (OD and OS) of 20/20 and 20/16 (♀) and 20/25 and 20/40 (♂), respectively, and suffered increased sensitivity to glare. Yellow irregular macular deposits, numerous small irregular hypo- and hyperreflective spots at the posterior pole, a patchy loss of photoreceptors, and retinal pigment epithelium (RPE) in the perifoveal region were seen. Electrophysiology showed dysfunction of rods and cones, with more affected cone dysfunction in the index patient, contrary to the generalised rod dysfunction in the brother of the index patient. The clinical, electrophysiological, and multimodal imaging findings of both siblings pointed towards Stargardt retinopathy with heterogenic presentation. The DNA analysis identified an autosomal dominant c.469 G>A p.(Asp157Asn) heterozygous pathogenic variant in PRPH2 associated with autosomal dominant cone-rod dystrophy and rod-cone dystrophy. PRPH2 codes for peripherin-2, a membrane protein that consists of 346 amino acids. CONCLUSIONS Our findings confirm a heterogeneity in clinical presentation associated with pathogenic variants in PRPH2. It may follow either an autosomal dominant or an autosomal recessive mode of inheritance and show a very heterogeneous clinical manifestation of retinal degeneration, e.g., autosomal dominant retinitis pigmentosa (♂ sibling; II-3) and autosomal dominant cone-rod dystrophy (index ♀ sibling; II-2), autosomal dominant macular dystrophy, and also autosomal recessive retinitis pigmentosa.
Collapse
Affiliation(s)
- Ayse Sanlialp
- Department of Ophthalmology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Pascal Escher
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - André Schaller
- Department of Human Genetics, Department of Pediatrics, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Margarita Todorova
- Department of Ophthalmology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| |
Collapse
|
2
|
Sanlialp A, Schumacher D, Kiper L, Varma E, Riechert E, Ho TC, Hofmann C, Kmietczyk V, Zimmermann F, Dlugosz S, Wirth A, Gorska AA, Burghaus J, Camacho Londoño JE, Katus HA, Doroudgar S, Freichel M, Völkers M. Saraf-dependent activation of mTORC1 regulates cardiac growth. J Mol Cell Cardiol 2020; 141:30-42. [PMID: 32173353 DOI: 10.1016/j.yjmcc.2020.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 03/03/2020] [Accepted: 03/09/2020] [Indexed: 10/24/2022]
Abstract
Pathological cardiac hypertrophy is an independent risk for heart failure (HF) and sudden death. Deciphering signaling pathways regulating intracellular Ca2+ homeostasis that control adaptive and pathological cardiac growth may enable identification of novel therapeutic targets. The objective of the present study is to determine the role of the store-operated calcium entry-associated regulatory factor (Saraf), encoded by the Tmem66 gene, on cardiac growth control in vitro and in vivo. Saraf is a single-pass membrane protein located at the sarco/endoplasmic reticulum and regulates intracellular calcium homeostasis. We found that Saraf expression was upregulated in the hypertrophied myocardium and was sufficient for cell growth in response to neurohumoral stimulation. Increased Saraf expression caused cell growth, which was associated with dysregulation of calcium-dependent signaling and sarcoplasmic reticulum calcium content. In vivo, Saraf augmented cardiac myocyte growth in response to angiotensin II and resulted in increased cardiac remodeling together with worsened cardiac function. Mechanistically, Saraf activated mTORC1 (mechanistic target of rapamycin complex 1) and increased protein synthesis, while mTORC1 inhibition blunted Saraf-dependent cell growth. In contrast, the hearts of Saraf knockout mice and Saraf-deficient myocytes did not show any morphological or functional alterations after neurohumoral stimulation, but Saraf depletion resulted in worsened cardiac function after acute pressure overload. SARAF knockout blunted transverse aortic constriction cardiac myocyte hypertrophy and impaired cardiac function, demonstrating a role for SARAF in compensatory myocyte growth. Collectively, these results reveal a novel link between sarcoplasmic reticulum calcium homeostasis and mTORC1 activation that is regulated by Saraf.
Collapse
Affiliation(s)
- Ayse Sanlialp
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Dagmar Schumacher
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany; Institute of Pharmacology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Leon Kiper
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Eshita Varma
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Eva Riechert
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Thanh Cao Ho
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Christoph Hofmann
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Vivien Kmietczyk
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Frank Zimmermann
- Interfacultary Biomedical Faculty (IBF), University of Heidelberg, Im Neuenheimer Feld 347, 69120 Heidelberg, Germany
| | - Sascha Dlugosz
- Interfacultary Biomedical Faculty (IBF), University of Heidelberg, Im Neuenheimer Feld 347, 69120 Heidelberg, Germany
| | - Angela Wirth
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany; Institute of Pharmacology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Agnieszka A Gorska
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Jana Burghaus
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Juan E Camacho Londoño
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany; Institute of Pharmacology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Shirin Doroudgar
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Marc Freichel
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany; Institute of Pharmacology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Mirko Völkers
- Department of Cardiology, Angiology, and Pneumology, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 669, 69120 Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany.
| |
Collapse
|