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Dubail J, Rondeau S, Michot C, Baujat G, Capri Y, Thévenon J, Charpie M, Pejin Z, Phan G, Huber C, Cormier-Daire V. Identification of kinesin family member (KIF22) homozygous variants in spondyloepimetaphyseal dysplasia with joint laxity, lepdodactylic type and demonstration of proteoglycan biosynthesis impairment. J Bone Miner Res 2024; 39:287-297. [PMID: 38477767 DOI: 10.1093/jbmr/zjad020] [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: 09/15/2023] [Revised: 11/19/2023] [Accepted: 11/23/2023] [Indexed: 03/14/2024]
Abstract
Heterozygous variants in KIF22, encoding a kinesin-like protein, are responsible for spondyloepimetaphyseal dysplasia with joint laxity, leptodactilic type (lepto-SEMDJL), characterized by short stature, flat face, generalized joint laxity with multiple dislocations, and progressive scoliosis and limb deformity. By targeted gene sequencing analysis, we identified a homozygous KIF22 variant (NM_007317.3: c.146G>A, p.Arg49Gln) in 3 patients from 3 unrelated families. The clinical features appeared similar to those of patients carrying heterozygous KIF22 variant (c.443C>T or c.446G>A), although the spinal involvement appeared later and was less severe in patients with a recessive variant. Relatives harboring the c.146G>A variant at the heterozygous state were asymptomatic. The homozygous KIF22 variant c.146G>A affected a conserved residue located in the active site and potentially destabilized ATP binding. RT-PCR and western blot analyses demonstrated that both dominant and recessive KIF22 variants do not affect KIF22 mRNA and protein expression in patient fibroblasts compared to controls. As lepto-SEMDJL presents phenotypic overlap with chondrodysplasias with multiple dislocations (CMD), related to defective proteoglycan biosynthesis, we analyzed proteoglycan synthesis in patient skin fibroblasts. Compared to controls, DMMB assay showed a significant decrease of total sulfated proteoglycan content in culture medium but not in the cell layer, and immunofluorescence demonstrated a strong reduction of staining for chondroitin sulfates but not for heparan sulfates, similarly in patients with recessive or dominant KIF22 variants. These data identify a new recessive KIF22 pathogenic variant and link for the first time KIF22 pathogenic variants to altered proteoglycan biosynthesis and place the lepto-SEMDJL in the CMD spectrum.
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Affiliation(s)
- Johanne Dubail
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
| | - Sophie Rondeau
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Reference Center for Skeletal Dysplasia, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
| | - Caroline Michot
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Reference Center for Skeletal Dysplasia, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
| | - Geneviève Baujat
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Reference Center for Skeletal Dysplasia, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
| | - Yline Capri
- Département de Génétique, Hôpital Robert Debré, APHP-Nord, Paris 75019, France
| | - Julien Thévenon
- Service de Génétique, Génomique et Procréation, Hôpital Couple-Enfant CHU Grenoble Alpes, Grenoble 38700, France
| | - Maelle Charpie
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Reference Center for Skeletal Dysplasia, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
| | - Zagorka Pejin
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Service de chirurgie orthopédique, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
| | - Gilles Phan
- Université Paris Cité, CNRS, CiTCoM, Paris 75006, France
| | - Céline Huber
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
| | - Valérie Cormier-Daire
- Paris Cité University, INSERM UMR 1163, Imagine Institute, Paris 75015, France
- Reference Center for Skeletal Dysplasia, Necker-Enfants Malades Hospital, AP-HP, Paris 75015, France
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Thompson AF, Blackburn PR, Arons NS, Stevens SN, Babovic-Vuksanovic D, Lian JB, Klee EW, Stumpff J. Pathogenic mutations in the chromokinesin KIF22 disrupt anaphase chromosome segregation. eLife 2022; 11:78653. [PMID: 35730929 PMCID: PMC9302971 DOI: 10.7554/elife.78653] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/21/2022] [Indexed: 11/22/2022] Open
Abstract
The chromokinesin KIF22 generates forces that contribute to mitotic chromosome congression and alignment. Mutations in the α2 helix of the motor domain of KIF22 have been identified in patients with abnormal skeletal development, and we report the identification of a patient with a novel mutation in the KIF22 tail. We demonstrate that pathogenic mutations do not result in a loss of KIF22’s functions in early mitosis. Instead, mutations disrupt chromosome segregation in anaphase, resulting in reduced proliferation, abnormal daughter cell nuclear morphology, and, in a subset of cells, cytokinesis failure. This phenotype could be explained by a failure of KIF22 to inactivate in anaphase. Consistent with this model, constitutive activation of the motor via a known site of phosphoregulation in the tail phenocopied the effects of pathogenic mutations. These results suggest that the motor domain α2 helix may be an important site for regulation of KIF22 activity at the metaphase to anaphase transition. In support of this conclusion, mimicking phosphorylation of α2 helix residue T158 also prevents inactivation of KIF22 in anaphase. These findings demonstrate the importance of both the head and tail of the motor in regulating the activity of KIF22 and offer insight into the cellular consequences of preventing KIF22 inactivation and disrupting force balance in anaphase.
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Affiliation(s)
- Alex F Thompson
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | | | - Noah S Arons
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Sarah N Stevens
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | | | - Jane B Lian
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Eric W Klee
- Biomedical Informatics, Mayo Clinic, Rochester, United States
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
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