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Aughey G, Cali E, Maroofian R, Zaki MS, Pagnamenta AT, Rahman F, Menzies L, Shafique A, Suri M, Roze E, Aguennouz M, Ghizlane Z, Saadi SM, Ali Z, Abdulllah U, Cheema HA, Anjum MN, Morel G, McFarland R, Altunoglu U, Kraus V, Shoukier M, Murphy D, Flemming K, Yttervik H, Rhouda H, Lesca G, Murtaza BN, Rehman MU, Consortium GE, Seo GH, Beetz C, Kayserili H, Krioulie Y, Chung WK, Naz S, Maqbool S, Gleeson J, Baig SM, Efthymiou S, Taylor JC, Severino M, Jepson JE, Houlden H. Clinical and neurogenetic characterisation of autosomal recessive RBL2-associated progressive neurodevelopmental disorder. medRxiv 2024:2024.05.03.24306631. [PMID: 38746364 PMCID: PMC11092723 DOI: 10.1101/2024.05.03.24306631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Retinoblastoma (RB) proteins are highly conserved transcriptional regulators that play important roles during development by regulating cell-cycle gene expression. RBL2 dysfunction has been linked to a severe neurodevelopmental disorder. However, to date, clinical features have only been described in six individuals carrying five biallelic predicted loss of function (pLOF) variants. To define the phenotypic effects of RBL2 mutations in detail, we identified and clinically characterized a cohort of 28 patients from 18 families carrying LOF variants in RBL2 , including fourteen new variants that substantially broaden the molecular spectrum. The clinical presentation of affected individuals is characterized by a range of neurological and developmental abnormalities. Global developmental delay and intellectual disability were uniformly observed, ranging from moderate to profound and involving lack of acquisition of key motor and speech milestones in most patients. Frequent features included postnatal microcephaly, infantile hypotonia, aggressive behaviour, stereotypic movements and non-specific dysmorphic features. Common neuroimaging features were cerebral atrophy, white matter volume loss, corpus callosum hypoplasia and cerebellar atrophy. In parallel, we used the fruit fly, Drosophila melanogaster , to investigate how disruption of the conserved RBL2 orthologueue Rbf impacts nervous system function and development. We found that Drosophila Rbf LOF mutants recapitulate several features of patients harboring RBL2 variants, including alterations in the head and brain morphology reminiscent of microcephaly, and perturbed locomotor behaviour. Surprisingly, in addition to its known role in controlling tissue growth during development, we find that continued Rbf expression is also required in fully differentiated post-mitotic neurons for normal locomotion in Drosophila , and that adult-stage neuronal re-expression of Rbf is sufficient to rescue Rbf mutant locomotor defects. Taken together, this study provides a clinical and experimental basis to understand genotype-phenotype correlations in an RBL2 -linked neurodevelopmental disorder and suggests that restoring RBL2 expression through gene therapy approaches may ameliorate aspects of RBL2 LOF patient symptoms.
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Efthymiou S, Kriouile Y, Salpietro V, Hajar R, Ghizlane Z, Mankad K, El Khorassani M, Aguennouz M, Houlden H, Wiethoff S. A rare PANK2 deletion in the first north African patient affected with pantothenate kinase associated neurodegeneration. J Neurol Sci 2019; 410:116639. [PMID: 31884352 DOI: 10.1016/j.jns.2019.116639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 10/25/2022]
Affiliation(s)
- Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Yamna Kriouile
- Unit of Neuropediatrics and Neurometabolism, Pediatric Department 2, Rabat Children's Hospital, Morocco
| | - Vincenzo Salpietro
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Rhouda Hajar
- Unit of Neuropediatrics and Neurometabolism, Pediatric Department 2, Rabat Children's Hospital, Morocco
| | - Zouiri Ghizlane
- Unit of Neuropediatrics and Neurometabolism, Pediatric Department 2, Rabat Children's Hospital, Morocco
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Mohamed El Khorassani
- Unit of Neuropediatrics and Neurometabolism, Pediatric Department 2, Rabat Children's Hospital, Morocco
| | - Mhammed Aguennouz
- Department of Clinical and Experimental Medicine, University of Messina, Sicily, Italy
| | | | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Sarah Wiethoff
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard Karls-University, Tübingen, Germany.
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