Journal of Human Genetics (2018) 63:811–820 https://doi.org/10.1038/s10038-018-0448-5 ARTICLE Osteogenesis imperfecta with ectopic mineralizations in dentin and cementum and a COL1A2 mutation Piranit Nik Kantaputra 1,2 ● Yuddhasert Sirirungruangsarn 3 ● Worrachet Intachai 1 ● Chumpol Ngamphiw 4 ● Sissades Tongsima 4 ● Prapai Dejkhamron 5 Received: 24 October 2017 / Revised: 11 March 2018 / Accepted: 12 March 2018 / Published online: 10 April 2018 © The Author(s) under exclusive licence to The Japan Society of Human Genetics 2018 Abstract We report a Thai father (patient 1) and his daughter (patient 2) affected with osteogenesis imperfecta type IV and dentinogenesis imperfecta. Both were heterozygous for the c.1451G>A (p.Gly484Glu) mutation in COL1A2. The father, a Thai boxer, had very mild osteogenesis imperfecta with no history of low-trauma bone fractures. Scanning electron micrography of the primary teeth with DI of the patient 2, and the primary teeth with DI of another OI patient with OI showed newly recognized dental manifestations of teeth with DI. Normal dentin and cementum might have small areas of ectopic mineralizations. Teeth affected with DI have well-organized ectopic mineralizations in dentin and cementum. The “French-fries-appearance” of the crystals at the cemento-dentinal junction and abnormal cementum have never been reported to be associated with dentinogenesis imperfecta, either isolated or osteogenesis imperfecta-associated. Our study shows for the first time that abnormal collagen fibers can lead to ectopic mineralization in dentin and cementum and abnormal cementum can be a part of osteogenesis imperfecta. Introduction Osteogenesis imperfecta (OI) is a phenotypically and molecularly heterogeneous group of inherited connective tissue disorders characterized by skeletal abnormalities with high susceptibility to bone fragility and deformity. Severity of the phenotypes ranges from perinatal death to barely unnoticeable clinical features. Most cases of OI are caused by mutations in two prominent collagen genes, COL1A1 (MIM #120150) and COL1A2 (MIM #120160), responsible for producing pro-α1(I) and pro-α1(II) chains, respectively. The majority of the previously reported mutations were glycine residue substitutions in the triple helix domain of the encoded protein [1, 2]. Phenotypes of OI are known to vary even within the same families. Herein, we report a father and his daughter, both affected with mild OI and dentinogenesis imperfecta (DI). Scanning electron micro- graphs (SEM) of teeth with DI showed newly recognized dental manifestations, bush-like ectopic mineralizations in dentin and cementum. This report shows varying clinical features of patients with OI. Furthermore, a patient with OI may have ectopic mineralization in dentin and cementum, and no bone fragility. Materials and methods Ethic statement The study was conducted in accordance with the Declara- tion of Helsinki and national guidelines. Informed consent * Piranit Nik Kantaputra dentaland17@gmail.com 1 Center of Excellence in Medical Genetics Research, Chiang Mai University; Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand 2 Dentaland Clinic, Chiang Mai, Thailand 3 Department of Orthopaedic surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 4 Genome Technology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand 5 Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Electronic supplementary material The online version of this article (https://doi.org/10.1038/s10038-018-0448-5) contains supplementary material, which is available to authorized users. 1234567890();,: 1234567890();,: