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Mäkitie RE, Pekkinen M, Morisada N, Kobayashi D, Yonezawa Y, Nishimura G, Ikegawa S, Mäkitie O. A Novel IFITM5 Variant Associated with Phenotype of Osteoporosis with Calvarial Doughnut Lesions: A Case Report. Calcif Tissue Int 2021; 109:626-632. [PMID: 34156493 PMCID: PMC8531111 DOI: 10.1007/s00223-021-00878-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/10/2021] [Indexed: 11/29/2022]
Abstract
Osteogenesis imperfecta (OI) and other decreased bone density disorders comprise a heterogeneous group of heritable diseases with skeletal fragility. Recently, it was discovered that mutations in SGMS2, encoding sphingomyelin synthetase 2, result in aberrant sphingomyelin metabolism and lead to a novel form of OI termed osteoporosis with calvarial doughnut lesions (OP-CDL) with moderate to severe skeletal fragility and variable cranial hyperostotic lesions. This study describes a Japanese family with the skeletal phenotype of OP-CDL. The affected individuals have moderately severe, childhood-onset skeletal fragility with multiple long-bone fractures, scoliosis and bone deformities. In addition, they exhibit multiple CDLs or calvarial bumps with central radiolucency and peripheral radiopacity. However, SGMS2 sequencing was normal. Instead, whole-exome sequencing identified a novel IFITM5 missense mutation c.143A>G (p.N48S) (classified as a VUS by ACMG). IFITM5 encodes an osteoblast-restricted protein BRIL and a recurrent c.-14C>T mutation in its 5' UTR region results in OI type V, a distinctive subtype of OI associated with hyperplastic callus formation and ossification of the interosseous membranes. The patients described here have a phenotype clearly different from OI type V and with hyperostotic cranial lesions, feature previously unreported in association with IFITM5. Our findings expand the genetic spectrum of OP-CDL, indicate diverse phenotypic consequences of pathogenic IFITM5 variants, and imply an important role for BRIL in cranial skeletogenesis.
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Affiliation(s)
- R E Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, P.O. Box 63, FIN-00014, Helsinki, Finland.
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Department of Otorhinolaryngology Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
| | - M Pekkinen
- Folkhälsan Institute of Genetics, University of Helsinki, P.O. Box 63, FIN-00014, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - N Morisada
- Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan
| | - D Kobayashi
- Department of Orthopaedic Surgery, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan
| | - Y Yonezawa
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences,, Yokohama, Japan
| | - G Nishimura
- Center for Intractable Disease, Saitama Medical University Hospital, Saitama, Japan
| | - S Ikegawa
- Laboratory for Bone and Joint Diseases, RIKEN Center for Integrative Medical Sciences,, Yokohama, Japan
| | - O Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, P.O. Box 63, FIN-00014, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Children's Hospital, University and Helsinki University Hospital, Helsinki, Finland
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Basalom S, Fiscaletti M, Miranda V, Huber C, Couture G, Drouin R, Monceau É, Wavrant S, Dubé J, Mäkitie O, Cormier-Daire V, Campeau PM. Calvarial doughnut lesions with bone fragility in a French-Canadian family; case report and review of the literature. Bone Rep 2021; 15:101121. [PMID: 34504906 PMCID: PMC8414042 DOI: 10.1016/j.bonr.2021.101121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/03/2021] [Accepted: 08/20/2021] [Indexed: 11/20/2022] Open
Abstract
Calvarial Doughnut Lesions with Bone Fragility (CDL) is an autosomal dominant genetic disease, characterized by low bone mineral density, multiple fractures starting in childhood, and sclerotic doughnut-shaped lesions in the cranial bones. Aubé and colleagues described in 1988 a French-Canadian family of 12 affected members who had a clinical diagnosis of doughnut lesions of the skull, with pathological fractures, osteopenia, "bone in bone" in the vertebral bodies and squaring of metatarsal and metacarpal bones. Herein we study new members of this family. Sequential genetic testing identified a nonsense variant c.148C>T, p. Arg50⁎ in SGMS2 previously reported in other families. SGMS2 encodes Sphingomyelin Synthase 2, which produces Sphingomyelin (SM), a major lipid component of the plasma membrane that plays a role in bone mineralization. The nonsense variant is associated with milder phenotype. The proband presents with bone in bone vertebral appearance that had been defined uniquely in the first cases described in the same family. The proband's son was identified to carry the same variant, which makes him the sixth generation with the diagnosis of CDL. We also report that the same pathogenic variant was identified in another previously described family, from France. These reports further confirm the genetic basis of CDL, the recurrence of the same variant (p.Arg50*) in individuals of the same ancestry, and the variable penetrance of some of the clinical findings.
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Affiliation(s)
- Shuaa Basalom
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Center, Montreal, QC H4A 3J1, Canada
| | - Mélissa Fiscaletti
- Department of Pediatrics, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | - Valancy Miranda
- Medical Genetics Division, Department of Pediatrics, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | - Céline Huber
- Department of Medical Genetics, INSERM UMR 1163, Paris Descartes-Sorbonne Paris Cité University, IMAGINE Institute, Necker Enfants Malades Hospital, Paris, France
| | | | - Régen Drouin
- Division of Medical Genetics, Department of Pediatrics, CHU de Quebec – ULaval, Faculty of Medicine, Université Laval, Quebec City, Canada
| | - Élise Monceau
- Department of Pediatrics, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | - Sandrine Wavrant
- Department of Obstetrics and Gynecology, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | - Johanne Dubé
- Department of Obstetrics and Gynecology, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
| | - Outi Mäkitie
- Children's Hospital and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, FI-00014 Helsinki, Finland
| | | | - Philippe M. Campeau
- Medical Genetics Division, Department of Pediatrics, CHU Sainte-Justine, Montreal, QC H3T 1C5, Canada
- Corresponding authors.
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