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Wallenius J, Kafantari E, Jhaveri E, Gorcenco S, Ameur A, Karremo C, Dobloug S, Karrman K, de Koning T, Ilinca A, Landqvist Waldö M, Arvidsson A, Persson S, Englund E, Ehrencrona H, Puschmann A. Exonic trinucleotide repeat expansions in ZFHX3 cause spinocerebellar ataxia type 4: A poly-glycine disease. Am J Hum Genet 2024; 111:82-95. [PMID: 38035881 PMCID: PMC10806739 DOI: 10.1016/j.ajhg.2023.11.008] [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: 10/23/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 12/02/2023] Open
Abstract
Autosomal-dominant ataxia with sensory and autonomic neuropathy is a highly specific combined phenotype that we described in two Swedish kindreds in 2014; its genetic cause had remained unknown. Here, we report the discovery of exonic GGC trinucleotide repeat expansions, encoding poly-glycine, in zinc finger homeobox 3 (ZFHX3) in these families. The expansions were identified in whole-genome datasets within genomic segments that all affected family members shared. Non-expanded alleles carried one or more interruptions within the repeat. We also found ZFHX3 repeat expansions in three additional families, all from the region of Skåne in southern Sweden. Individuals with expanded repeats developed balance and gait disturbances at 15 to 60 years of age and had sensory neuropathy and slow saccades. Anticipation was observed in all families and correlated with different repeat lengths determined through long-read sequencing in two family members. The most severely affected individuals had marked autonomic dysfunction, with severe orthostatism as the most disabling clinical feature. Neuropathology revealed p62-positive intracytoplasmic and intranuclear inclusions in neurons of the central and enteric nervous system, as well as alpha-synuclein positivity. ZFHX3 is located within the 16q22 locus, to which spinocerebellar ataxia type 4 (SCA4) repeatedly had been mapped; the clinical phenotype in our families corresponded well with the unique phenotype described in SCA4, and the original SCA4 kindred originated from Sweden. ZFHX3 has known functions in neuronal development and differentiation n both the central and peripheral nervous system. Our findings demonstrate that SCA4 is caused by repeat expansions in ZFHX3.
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Affiliation(s)
- Joel Wallenius
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Efthymia Kafantari
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Emma Jhaveri
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Sorina Gorcenco
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 23 Uppsala, Sweden
| | - Christin Karremo
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Sigurd Dobloug
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden; Department of Neurology, Helsingborg General Hospital, 252 23 Helsingborg, Sweden
| | - Kristina Karrman
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, 222 42 Lund, Sweden; Department of Clinical Genetics, Pathology and Molecular Diagnostics, Office for Medical Services, Region Skåne, 221 85 Lund, Sweden
| | - Tom de Koning
- Pediatrics, Department of Clinical Sciences Lund, Lund University, 221 84 Lund, Sweden
| | - Andreea Ilinca
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Maria Landqvist Waldö
- Division of Clinical Sciences Helsingborg, Department of Clinical Sciences Lund, Lund University, 221 84 Lund, Sweden
| | - Andreas Arvidsson
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Staffan Persson
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Elisabet Englund
- Department of Clinical Genetics, Pathology and Molecular Diagnostics, Office for Medical Services, Region Skåne, 221 85 Lund, Sweden; Pathology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden
| | - Hans Ehrencrona
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, 222 42 Lund, Sweden; Department of Clinical Genetics, Pathology and Molecular Diagnostics, Office for Medical Services, Region Skåne, 221 85 Lund, Sweden
| | - Andreas Puschmann
- Neurology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, 222 42 Lund, Sweden; SciLifeLab National Research Infrastructure, Lund University, 221 84 Lund, Sweden.
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Thunström S, Axelsson M. Leukoencephalopathia, demyelinating peripheral neuropathy and dural ectasia explained by a not formerly described de novo mutation in the SAMD9L gene, ends 27 years of investigations - a case report. BMC Neurol 2019; 19:89. [PMID: 31053103 PMCID: PMC6499956 DOI: 10.1186/s12883-019-1319-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/26/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Missense mutations in SAMD9L gene is associated with ataxia-pancytopenia syndrome (ATXPC), OMIM#159550. Common clinical features in these patients include neurological and hematological symptoms. The phenotype and age of onset is variable. CASE PRESENTATION In this case report whole exome sequencing (WES) revealed a not previously reported de novo variant c.2686 T > G, p.(Phe896Val) in SAMD9L in a patient with widespread findings of slow developing pathology in the peripheral and central nervous system. The clinical picture was dominated by neurological symptoms, unlike previously described cases, and in addition dural ectasias and multiple cysts in the brain was observed using magnetic resonance imaging. CONCLUSIONS This case underscores the effect of variable expressivity, i.e. different mutations in the same gene can cause different phenotypes.
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Affiliation(s)
- Sofia Thunström
- Department of Clinical Genetics, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Markus Axelsson
- Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
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Davidsson J, Puschmann A, Tedgård U, Bryder D, Nilsson L, Cammenga J. SAMD9 and SAMD9L in inherited predisposition to ataxia, pancytopenia, and myeloid malignancies. Leukemia 2018. [PMID: 29535429 PMCID: PMC5940635 DOI: 10.1038/s41375-018-0074-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Germline mutations in the SAMD9 and SAMD9L genes, located in tandem on chromosome 7, are associated with a clinical spectrum of disorders including the MIRAGE syndrome, ataxia-pancytopenia syndrome and myelodysplasia and leukemia syndrome with monosomy 7 syndrome. Germline gain-of-function mutations increase SAMD9 or SAMD9L's normal antiproliferative effect. This causes pancytopenia and generally restricted growth and/or specific organ hypoplasia in non-hematopoietic tissues. In blood cells, additional somatic aberrations that reverse the germline mutation's effect, and give rise to the clonal expansion of cells with reduced or no antiproliferative effect of SAMD9 or SAMD9L include complete or partial chromosome 7 loss or loss-of-function mutations in SAMD9 or SAMD9L. Furthermore, the complete or partial loss of chromosome 7q may cause myelodysplastic syndrome in these patients. SAMD9 mutations appear to associate with a more severe disease phenotype, including intrauterine growth restriction, developmental delay and hypoplasia of adrenal glands, testes, ovaries or thymus, and most reported patients died in infancy or early childhood due to infections, anemia and/or hemorrhages. SAMD9L mutations have been reported in a few families with balance problems and nystagmus due to cerebellar atrophy, and may lead to similar hematological disease as seen in SAMD9 mutation carriers, from early childhood to adult years. We review the clinical features of these syndromes, discuss the underlying biology, and interpret the genetic findings in some of the affected family members. We provide expert-based recommendations regarding diagnosis, follow-up, and treatment of mutation carriers.
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Affiliation(s)
- Josef Davidsson
- Department of Pediatric Hematology and Oncology, Skåne University Hospital, Lund, Sweden. .,Department of Molecular Hematology, Lund University, Lund, Sweden.
| | - Andreas Puschmann
- Skåne University Hospital, Department of Clinical Sciences Lund, Neurology, Lund University, Lund, Sweden
| | - Ulf Tedgård
- Department of Pediatric Hematology and Oncology, Skåne University Hospital, Lund, Sweden
| | - David Bryder
- Department of Molecular Hematology, Lund University, Lund, Sweden
| | - Lars Nilsson
- Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Jörg Cammenga
- Department of Hematology, University Hospital Linköping, Linköping, Sweden. .,Institution for Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
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Abstract
Infantile-onset saccade initiation delay, also known as congenital ocular motor apraxia, typically presents in early infancy with horizontal head thrusts once head control is achieved. Defective initiation of horizontal saccades and saccade hypometria with normal saccadic velocity are characteristic findings. Isolated impairment of vertical saccades is rare. Impaired smooth ocular pursuit may be seen. Other relatively common features include developmental delay, hypotonia, ataxia, or clumsiness. Brain MRI may be normal or show a diverse range of abnormalities, most commonly involving the cerebellum. Defective slow phases of the optokinetic response are commonly associated with brain MRI abnormalities. Isolated defect of vertical saccade initiation may indicate supratentorial brain abnormalities on MRI. Joubert syndrome, a developmental midbrain-hindbrain malformation, and ataxia telangiectasia are both commonly associated with defective volitional and reflexive saccade initiation, saccade hypometria, and head thrusts. Both horizontal and vertical saccades are impaired in these two disorders.
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Affiliation(s)
- Michael S Salman
- Winnipeg Children's Hospital and Section of Pediatric Neurology, Department of Pediatrics and Child Health, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada,
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