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Xu Z, Sadleir L, Goel H, Jiao X, Niu Y, Zhou Z, de Valles-Ibáñez G, Poke G, Hildebrand M, Lieffering N, Qin J, Yang Z. Genotype and phenotype correlation of PHACTR1-related neurological disorders. J Med Genet 2024; 61:536-542. [PMID: 38272663 DOI: 10.1136/jmg-2023-109638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
BACKGROUND PHACTR1 (phosphatase and actin regulators) plays a key role in cortical migration and synaptic activity by binding and regulating G-actin and PPP1CA. This study aimed to expand the genotype and phenotype of patients with de novo variants in PHACTR1 and analyse the impact of variants on protein-protein interaction. METHODS We identified seven patients with PHACTR1 variants by trio-based whole-exome sequencing. Additional two subjects were ascertained from two centres through GeneMatcher. The genotype-phenotype correlation was determined, and AlphaFold-Multimer was used to predict protein-protein interactions and interfaces. RESULTS Eight individuals carried missense variants and one had CNV in the PHACTR1. Infantile epileptic spasms syndrome (IESS) was the unifying phenotype in eight patients with missense variants of PHACTR1. They could present with other types of seizures and often exhibit drug-resistant epilepsy with a poor prognosis. One patient with CNV displayed a developmental encephalopathy phenotype. Using AlphaFold-Multimer, our findings indicate that PHACTR1 and G-actin-binding sequences overlap with PPP1CA at the RPEL3 domain, which suggests possible competition between PPP1CA and G-actin for binding to PHACTR1 through a similar polymerisation interface. In addition, patients carrying missense variants located at the PHACTR1-PPP1CA or PHACTR1-G-actin interfaces consistently exhibit the IESS phenotype. These missense variants are mostly concentrated in the overlapping sequence (RPEL3 domain). CONCLUSIONS Patients with variants in PHACTR1 can have a phenotype of developmental encephalopathy in addition to IESS. Moreover, our study confirmed that the variants affect the binding of PHACTR1 to G-actin or PPP1CA, resulting in neurological disorders in patients.
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Affiliation(s)
- Zhao Xu
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
| | - Lynette Sadleir
- Department of Paediatrics and Child Health, University of Otago Wellington, Wellington, New Zealand
| | - Himanshu Goel
- Hunter Genetics, Waratah, New South Wales, Australia
| | - Xianru Jiao
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
| | - Yue Niu
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
| | - Zongpu Zhou
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
| | - Guillem de Valles-Ibáñez
- Department of Paediatrics and Child Health, University of Otago Wellington, Wellington, New Zealand
| | - Gemma Poke
- Department of Paediatrics and Child Health, University of Otago Wellington, Wellington, New Zealand
| | - Michael Hildebrand
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Heidelberg, Victoria, Australia
- Neuroscience Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, South Brisbane, Queensland, Australia
| | - Nico Lieffering
- Department of Paediatrics and Child Health, University of Otago Wellington, Wellington, New Zealand
| | - Jiong Qin
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University People's Hospital, Beijing, China
- Epilepsy Center, Peking University People's Hospital, Beijing, China
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Kodirov SA. Adam, amigo, brain, and K channel. Biophys Rev 2023; 15:1393-1424. [PMID: 37975011 PMCID: PMC10643815 DOI: 10.1007/s12551-023-01163-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 09/28/2023] [Indexed: 11/19/2023] Open
Abstract
Voltage-dependent K+ (Kv) channels are diverse, comprising the classical Shab - Kv2, Shaker - Kv1, Shal - Kv4, and Shaw - Kv3 families. The Shaker family alone consists of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv1.6, and Kv1.7. Moreover, the Shab family comprises two functional (Kv2.1 and Kv2.2) and several "silent" alpha subunits (Kv2.3, Kv5, Kv6, Kv8, and Kv9), which do not generate K current. However, e.g., Kv8.1, via heteromerization, inhibits outward currents of the same family or even that of Shaw. This property of Kv8.1 is similar to those of designated beta subunits or non-selective auxiliary elements, including ADAM or AMIGO proteins. Kv channels and, in turn, ADAM may modulate the synaptic long-term potentiation (LTP). Prevailingly, Kv1.1 and Kv1.5 are attributed to respective brain and heart pathologies, some of which may occur simultaneously. The aforementioned channel proteins are apparently involved in several brain pathologies, including schizophrenia and seizures.
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Affiliation(s)
- Sodikdjon A. Kodirov
- Department of Biological Sciences, University of Texas at Brownsville, Brownsville, TX 78520 USA
- Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
- Instituto de Medicina Molecular, Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Almazov Federal Heart, Blood and Endocrinology Centre, Saint Petersburg, 197341 Russia
- Institute for Physiology and Pathophysiology, Johannes Kepler University, Linz, Austria
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Previtali R, Leidi A, Basso M, Izzo G, Stignani C, Spaccini L, Iascone M, Veggiotti P, Bova SM. Case report: Early-onset parkinsonism among the neurological features in children with PHACTR1 variants. Front Neurol 2023; 14:1181015. [PMID: 37483454 PMCID: PMC10359812 DOI: 10.3389/fneur.2023.1181015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
PACHTR1 is expressed in cardiovascular and neurological tissues. In the brain, it has a role in pre- and post-natal maturation. Previously reported PHACTR1-mutated patients showed early-onset epilepsy and intellectual disability. We describe two unreported cases with de novo pathogenic variants in PHACTR1 and their clinical pictures, compared with those of cases already reported in the literature. In line with previous reports, the two patients presented early-onset developmental and epileptic encephalopathy. In addition, one patient developed a speech disorder and a progressive movement disorder characterized by hypertonus, hypo-bradykinesia, hypomimia, ataxic gait, and retropulsion. She was treated with levodopa without any clinical improvement. Pathogenic variants in PHACTR1 may result in a cardiological or neurological phenotype. Severe developmental delay, intellectual disability, and early-onset developmental and epileptic encephalopathy are the main features of PHACTR1-mutated patients with neurological involvement. Movement and speech disorders have never previously been described and could be new features of the neurological phenotype.
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Affiliation(s)
| | | | | | - Giana Izzo
- Department of Pediatric Radiology and Neuroradiology, V. Buzzi Children's Hospital, Milan, Italy
| | - Cecilia Stignani
- Department of Pediatric Orthopedics, V. Buzzi Children's Hospital, Milan, Italy
| | - Luigina Spaccini
- Clinical Genetics Unit, Department of Obstetrics and Gynecology, V. Buzzi Children's Hospital, University of Milan, Milan, Italy
| | - Maria Iascone
- Molecular Genetics Section, Medical Genetics Laboratory, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Pierangelo Veggiotti
- Department of Biomedical and Clinical Sciences, L. Sacco, University of Milan, Milan, Italy
- Pediatric Neurology Unit, Vittore Buzzi Children's Hospital, Milan, Italy
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