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Morison LD, Kennis MGP, Rots D, Bouman A, Kummeling J, Palmer E, Vogel AP, Liegeois F, Brignell A, Srivastava S, Frazier Z, Milnes D, Goel H, Amor DJ, Scheffer IE, Kleefstra T, Morgan AT. Expanding the phenotype of Kleefstra syndrome: speech, language and cognition in 103 individuals. J Med Genet 2024; 61:578-585. [PMID: 38290825 PMCID: PMC11148766 DOI: 10.1136/jmg-2023-109702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/18/2024] [Indexed: 02/01/2024]
Abstract
OBJECTIVES Speech and language impairments are core features of the neurodevelopmental genetic condition Kleefstra syndrome. Communication has not been systematically examined to guide intervention recommendations. We define the speech, language and cognitive phenotypic spectrum in a large cohort of individuals with Kleefstra syndrome. METHOD 103 individuals with Kleefstra syndrome (40 males, median age 9.5 years, range 1-43 years) with pathogenic variants (52 9q34.3 deletions, 50 intragenic variants, 1 balanced translocation) were included. Speech, language and non-verbal communication were assessed. Cognitive, health and neurodevelopmental data were obtained. RESULTS The cognitive spectrum ranged from average intelligence (12/79, 15%) to severe intellectual disability (12/79, 15%). Language ability also ranged from average intelligence (10/90, 11%) to severe intellectual disability (53/90, 59%). Speech disorders occurred in 48/49 (98%) verbal individuals and even occurred alongside average language and cognition. Developmental regression occurred in 11/80 (14%) individuals across motor, language and psychosocial domains. Communication aids, such as sign and speech-generating devices, were crucial for 61/103 (59%) individuals including those who were minimally verbal, had a speech disorder or following regression. CONCLUSIONS The speech, language and cognitive profile of Kleefstra syndrome is broad, ranging from severe impairment to average ability. Genotype and age do not explain the phenotypic variability. Early access to communication aids may improve communication and quality of life.
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Affiliation(s)
- Lottie D Morison
- Speech and Language, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Milou G P Kennis
- Department of Clinical Genetics, Radboudumc, Nijmegen, Netherlands
| | - Dmitrijs Rots
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Arianne Bouman
- Department of Clinical Genetics, Radboudumc, Nijmegen, Netherlands
| | - Joost Kummeling
- Department of Clinical Genetics, Radboudumc, Nijmegen, Netherlands
| | - Elizabeth Palmer
- Sydney Children's Hospital Network, Randwick, New South Wales, Australia
- Discipline of Paediatrics and Child Health, Faculty of Medicine and Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Adam P Vogel
- Department of Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia
- Redenlab, Melbourne, Victoria, Australia
| | - Frederique Liegeois
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Amanda Brignell
- Department of Paediatrics, Monash University, Clayton, Victoria, Australia
- Department of Developmental Paediatrics, Monash Children's Hospital, Clayton, Victoria, Australia
| | | | - Zoe Frazier
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Di Milnes
- Genetic Health Queensland, Herston, Queensland, Australia
| | - Himanshu Goel
- Hunter Genetics, Waratah, New South Wales, Australia
| | - David J Amor
- Speech and Language, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Ingrid E Scheffer
- Melbourne Brain Centre, Austin Health, Heidelberg, Victoria, Australia
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Tjitske Kleefstra
- Department of Clinical Genetics, Radboudumc, Nijmegen, Netherlands
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Angela T Morgan
- Speech and Language, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia
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Morgan AT, Amor DJ, St John MD, Scheffer IE, Hildebrand MS. Genetic architecture of childhood speech disorder: a review. Mol Psychiatry 2024; 29:1281-1292. [PMID: 38366112 PMCID: PMC11189821 DOI: 10.1038/s41380-024-02409-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 02/18/2024]
Abstract
Severe speech disorders lead to poor literacy, reduced academic attainment and negative psychosocial outcomes. As early as the 1950s, the familial nature of speech disorders was recognized, implying a genetic basis; but the molecular genetic basis remained unknown. In 2001, investigation of a large three generational family with severe speech disorder, known as childhood apraxia of speech (CAS), revealed the first causative gene; FOXP2. A long hiatus then followed for CAS candidate genes, but in the past three years, genetic analysis of cohorts ascertained for CAS have revealed over 30 causative genes. A total of 36 pathogenic variants have been identified from 122 cases across 3 cohorts in this nascent field. All genes identified have been in coding regions to date, with no apparent benefit at this stage for WGS over WES in identifying monogenic conditions associated with CAS. Hence current findings suggest a remarkable one in three children have a genetic variant that explains their CAS, with significant genetic heterogeneity emerging. Around half of the candidate genes identified are currently supported by medium (6 genes) to strong (9 genes) evidence supporting the association between the gene and CAS. Despite genetic heterogeneity; many implicated proteins functionally converge on pathways involved in chromatin modification or transcriptional regulation, opening the door to precision diagnosis and therapies. Most of the new candidate genes for CAS are associated with previously described neurodevelopmental conditions that include intellectual disability, autism and epilepsy; broadening the phenotypic spectrum to a distinctly milder presentation defined by primary speech disorder in the setting of normal intellect. Insights into the genetic bases of CAS, a severe, rare speech disorder, are yet to translate to understanding the heritability of more common, typically milder forms of speech or language impairment such as stuttering or phonological disorder. These disorders likely follow complex inheritance with polygenic contributions in many cases, rather than the monogenic patterns that underly one-third of patients with CAS. Clinical genetic testing for should now be implemented for individuals with CAS, given its high diagnostic rate, which parallels many other neurodevelopmental disorders where this testing is already standard of care. The shared mechanisms implicated by gene discovery for CAS highlight potential new targets for future precision therapies.
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Affiliation(s)
- Angela T Morgan
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.
- Speech Pathology, University of Melbourne, Melbourne, VIC, Australia.
- Speech Pathology, Royal Children's Hospital, Melbourne, VIC, Australia.
| | - David J Amor
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Miya D St John
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Speech Pathology, University of Melbourne, Melbourne, VIC, Australia
| | - Ingrid E Scheffer
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Epilepsy Research Centre, Austin Health, Melbourne, VIC, Australia
| | - Michael S Hildebrand
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Epilepsy Research Centre, Austin Health, Melbourne, VIC, Australia
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Ng R, Harris J, Kleefstra T, Morgan AT, Simpson B. Editorial: Characterizing the neurobehavioral phenotype of mendelian disorders of epigenetic machinery. Front Genet 2023; 14:1338078. [PMID: 38116293 PMCID: PMC10728862 DOI: 10.3389/fgene.2023.1338078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023] Open
Affiliation(s)
- Rowena Ng
- Department of Neuropsychology, Kennedy Krieger Institute, Baltimore, MD, United States
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jacqueline Harris
- Kennedy Krieger Institute, Baltimore, MD, United States
- Department of Genetic Medicine, Pediatrics and Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Tjitske Kleefstra
- Department of Human Genetics and Psychiatry, Radboud University Medical Center, Venray, Netherlands
- Centre of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, Netherlands
| | - Angela T. Morgan
- Speech and Language, Murdoch Children’s Research Institute, Parkville, VIC, Australia
- Department of Audiology and Speech Pathology, University of Melbourne, Parkville, VIC, Australia
- Speech Genomics Clinic, Royal Children’s Hospital, Parkville, VIC, Australia
| | - Brittany Simpson
- Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, Division of Human Genetics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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