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Wang RL, Ruan DD, Hu YN, Gan YM, Lin XF, Fang ZT, Liao LS, Tang FQ, He WB, Luo JW. Genetic Analysis and Functional Study of a Pedigree With Bruck Syndrome Caused by PLOD2 Variant. Front Pediatr 2022; 10:878172. [PMID: 35601416 PMCID: PMC9120662 DOI: 10.3389/fped.2022.878172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Bruck syndrome (BS) is a rare autosomal recessive inherited osteogenesis imperfecta disease characterized by increased bone fragility and joint contracture. The pathogenic gene of type I BS is FKBPl0, whereas that of type II BS is PLOD2. No significant difference has been found in the clinical phenotype between the two types of BS. In this study, we performed genetic analysis of a BS pedigree caused by PLOD2 variant and studied the corresponding cellular function. METHODS Serum biochemistry, parathyroid hormone (PTH), 25-hydroxyvitamin D [25-(OH) D], osteocalcin, and 24-h urinary calcium levels of a family member with BS was assessed. The genes of the proband were analyzed by second-generation sequencing and exon capture techniques. Sanger sequencing was also performed for the suspected responsible variant of the family member. Wild- and variant-type lentivirus plasmids were constructed by gene cloning and transfected into HEK293T cells. Cell function was verified by real-time quantitative polymerase chain reaction, western blotting, and immunofluorescence detection. RESULTS In this pedigree, the proband was found to have a homozygous variant c.1856G > A (p.Arg619His) in exon 17 of PLOD2 (NM_182943.3). His consanguineous parents and sisters were p.Arg619His heterozygous carriers. The mRNA expression of PLOD2 in the constructed p.Arg619His variant cells was significantly upregulated, while the expression of PLOD2 and collagen I protein in the cell lysate was significantly downregulated. Immunofluorescence revealed that the wild-type PLOD2 was mainly located in the cytoplasm, and the expression of the PLOD2 protein after c.1856G > A variant was significantly downregulated, with almost no expression, aligning with the western blot results. The serum sodium, potassium, calcium, phosphorus, magnesium, alkaline phosphatase, PTH, 25-(OH) D, osteocalcin, and 24 h urinary calcium levels of the proband, his parents, and sisters were normal. CONCLUSION Through gene and cell function analyses, PLOD2 Arg619His missense variant was preliminarily confirmed to cause BS by reducing protein expression.
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Affiliation(s)
- Ruo-Li Wang
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Emergency, Fujian Provincial Hospital, Fuzhou, China.,Fujian Trauma Medical Center, Fuzhou, China
| | - Dan-Dan Ruan
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China
| | - Ya-Nan Hu
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China
| | - Yu-Mian Gan
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China
| | - Xin-Fu Lin
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Pediatrics, Fujian Provincial Hospital, Fuzhou, China
| | - Zhu-Ting Fang
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Intervention, Fujian Provincial Hospital, Fuzhou, China
| | - Li-Sheng Liao
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Hematology, Fujian Provincial Hospital, Fuzhou, China
| | - Fa-Qiang Tang
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Orthopedics, Fujian Provincial Hospital, Fuzhou, China
| | - Wu-Bing He
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Emergency, Fujian Provincial Hospital, Fuzhou, China.,Fujian Trauma Medical Center, Fuzhou, China
| | - Jie-Wei Luo
- Shengli Clinical Medical College, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, China.,Department of Traditional Chinese Medicine, Fujian Provincial Hospital, Fuzhou, China
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Mumm S, Gottesman GS, Wenkert D, Campeau PM, Nenninger A, Huskey M, Bijanki VN, Veis DJ, Barnes AM, Marini JC, Stolina M, Zhang F, McAlister WH, Whyte MP. Bruck syndrome 2 variant lacking congenital contractures and involving a novel compound heterozygous PLOD2 mutation. Bone 2020; 130:115047. [PMID: 31472299 PMCID: PMC6945817 DOI: 10.1016/j.bone.2019.115047] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/13/2019] [Accepted: 08/22/2019] [Indexed: 02/07/2023]
Abstract
Bruck syndrome (BRKS) is the rare disorder that features congenital joint contractures often with pterygia and subsequent fractures, also known as osteogenesis imperfecta (OI) type XI (OMIM # 610968). Its two forms, BRKS1 (OMIM # 259450) and BRKS2 (OMIM # 609220), reflect autosomal recessive (AR) inheritance of FKBP10 and PLOD2 loss-of-function mutations, respectively. A 10-year-old girl was referred with blue sclera, osteopenia, poorly-healing fragility fractures, Wormian skull bones, cleft soft palate, congenital fusion of cervical vertebrae, progressive scoliosis, bell-shaped thorax, restrictive and reactive pulmonary disease, protrusio acetabuli, short stature, and additional dysmorphic features without joint contractures. Iliac crest biopsy after alendronate treatment that improved her bone density revealed low trabecular connectivity, abundant patchy osteoid, and active bone formation with widely-spaced tetracycline labels. Chromosome 22q11 deletion analysis for velocardiofacial syndrome, COL1A1 and COL1A2 sequencing for prevalent types of OI, and Sanger sequencing of LRP5, PPIB, FKBP10, and IFITM5 for rare pediatric osteoporoses were negative. Copy number microarray excluded a contiguous gene syndrome. Instead, exome sequencing revealed two missense variants in PLOD2 which encodes procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (lysyl hydroxylase 2, LH2); exon 8, c.797G>T, p.Gly266Val (paternal), and exon 12, c.1280A>G, p.Asn427Ser (maternal). In the Exome Aggregation Consortium (ExAC) database, low frequency (Gly266Val, 0.0000419) and absence (Asn427Ser) implicated both variants as mutations of PLOD2. The father, mother, and sister (who carried the exon 12 defect) were reportedly well with normal parental DXA findings. BRKS2, characterized by under-hydroxylation of type I collagen telopeptides compromising their crosslinking, has been reported in at least 16 probands/families. Most PLOD2 mutations involve exons 17-19 (of 20 total) encoding the C-terminal domain with LH activity. However, truncating defects (nonsense, frameshift, splice site mutations) are also found throughout PLOD2. In three reports, AR PLOD2 mutations are not associated with congenital contractures. Our patient's missense defects lie within the central domain of unknown function of PLOD2. In our patient, compound heterozygosity with PLOD2 mutations is associated with a clinical phenotype distinctive from classic BRKS2 indicating that when COL1A1 and COL1A2 mutation testing is negative for OI without congenital contractures or pterygia, atypical BRKS should be considered.
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Affiliation(s)
- Steven Mumm
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Gary S Gottesman
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA.
| | - Deborah Wenkert
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA.
| | - Philippe M Campeau
- Department of Pediatrics, University of Montreal, Montreal, Quebec H3T 1C5, Canada.
| | - Angela Nenninger
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA.
| | - Margaret Huskey
- Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Vinieth N Bijanki
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA.
| | - Deborah J Veis
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Aileen M Barnes
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Joan C Marini
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Marina Stolina
- Amgen Research, Amgen Inc., Thousand Oaks, CA 91320, USA.
| | - Fan Zhang
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA.
| | - William H McAlister
- Mallinckrodt Institute of Radiology, Washington University School of Medicine at St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children-St. Louis, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Scietti L, Campioni M, Forneris F. SiMPLOD, a Structure-Integrated Database of Collagen Lysyl Hydroxylase (LH/PLOD) Enzyme Variants. J Bone Miner Res 2019; 34:1376-1382. [PMID: 30721533 DOI: 10.1002/jbmr.3692] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/09/2019] [Accepted: 01/26/2019] [Indexed: 12/17/2022]
Abstract
PLOD genes encode for procollagen lysyl hydroxylase enzymes (LH/PLOD), a family of proteins essential for collagen biosynthesis. Several mutations affect these genes, causing severe disorders, such as Ehlers-Danlos and Bruck syndrome, as well a connective tissue disease with phenotype resembling osteogenesis imperfecta caused by lack of LH3 functions. The recently determined three-dimensional (3D) structures of the full-length human LH3/PLOD3 isoform, together with the structure of a fragment of a viral LH/PLOD homolog, are now allowing molecular mapping of the numerous disease-causing mutations, providing insights often suitable for the interpretation of the resulting disease phenotypes. However, the added value of molecular structure interpretation is affected by the limited accessibility of complex molecular data to scientific communities lacking direct expertise in structural biology. In this work, we present a Structurally-integrated database for Mutations of PLOD genes (SiMPLOD), a publicly-available manually-curated online database with an embedded molecular viewer interface for the visualization and interpretation of LH/PLOD mutations on available molecular models. Each SiMPLOD entry is accompanied by manual annotations extrapolated from literature references and comments about the localization of the amino acid variants on the molecular structure. Additional links to the appropriate online resources for clinically-relevant as well as biochemical data are also provided in a standardized format. The web application is available at http://fornerislab.unipv.it/SiMPLOD. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Luigi Scietti
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Matteo Campioni
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
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