1
|
Arunachalam AK, Aboobacker FN, Sampath E, Devasia AJ, Korula A, George B, Edison ES. Molecular Heterogeneity of Osteopetrosis in India: Report of 17 Novel Variants. Indian J Hematol Blood Transfus 2024; 40:494-503. [PMID: 39011244 PMCID: PMC11246401 DOI: 10.1007/s12288-023-01732-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 12/26/2023] [Indexed: 07/17/2024] Open
Abstract
Osteopetrosis is a clinically and genetically heterogeneous group of inherited bone disorders that is caused by defects in osteoclast formation or function. Treatment options vary with the disease severity and an accurate molecular diagnosis helps in prognostication and treatment decisions. We investigated the genetic causes of osteopetrosis in 31 unrelated patients of Indian origin. Screening for the genetic variants was done by Sanger sequencing or next generation sequencing in 48 samples that included 31 samples from index patients, 16 from parents' and 1 chorionic villus sample. A total of 30 variants, including 29 unique variants, were identified in 26 of the 31 patients in the study. TCIRG1 was the most involved gene (n = 14) followed by TNFRSF11A (n = 4) and CLCN7 (n = 3). A total of 17 novel variants were identified. Prenatal diagnosis was done in one family and the foetus showed homozygous c.807 + 2T > G variant in TCIRG1. Molecular diagnosis of osteopetrosis aids in therapeutic decisions including the need for a stem cell transplantation and gives a possible option of performing prenatal diagnosis in affected families. Further studies would help in understanding the genetic etiology in patients where no variants were identified. Supplementary Information The online version contains supplementary material available at 10.1007/s12288-023-01732-4.
Collapse
Affiliation(s)
| | - Fouzia N. Aboobacker
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu 632517 India
| | - Eswari Sampath
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu 632517 India
| | - Anup J. Devasia
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu 632517 India
| | - Anu Korula
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu 632517 India
| | - Biju George
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu 632517 India
| | | |
Collapse
|
2
|
Udupa P, Ghosh DK, Kausthubham N, Shah H, Bartakke S, Dalal A, Girisha KM, Bhavani GS. Genome sequencing identifies a large non-coding region deletion of SNX10 causing autosomal recessive osteopetrosis. J Hum Genet 2023; 68:287-290. [PMID: 36526684 PMCID: PMC10040338 DOI: 10.1038/s10038-022-01104-2] [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: 05/27/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
Autosomal recessive osteopetrosis (ARO) is a rare genetic disorder caused by impaired osteoclast activity. In this study, we describe a 4-year-old boy with increased bone density due to osteopetrosis, autosomal recessive 8. Using genome sequencing, we identified a large deletion in the 5'-untranslated region (UTR) of SNX10 (sorting nexin 10), where the regulatory region of this gene is located. This large deletion resulted in the absence of the SNX10 transcript and led to abnormal osteoclast activity. SNX10 is one of the nine genes known to cause ARO, shown to interact with V-ATPase (vacuolar type H( + )-ATPase), as it plays an important role in bone resorption. Our study highlights the importance of regulatory regions in the 5'-UTR of SNX10 for its expression while also demonstrating the importance of genome sequencing for detecting large deletion of the regulatory region of SNX10.
Collapse
Affiliation(s)
- Prajna Udupa
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Debasish Kumar Ghosh
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Neethukrishna Kausthubham
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Hitesh Shah
- Department of Pediatric Orthopedics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Sandip Bartakke
- Department of Clinical Hematology, Aditya Birla Memorial Hospital, Pune, India
| | - Ashwin Dalal
- Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Gandham SriLakshmi Bhavani
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.
| |
Collapse
|
3
|
Schulz A, Moshous D. Hematopoietic stem cell transplantation, a curative approach in infantile osteopetrosis. Bone 2023; 167:116634. [PMID: 36470372 DOI: 10.1016/j.bone.2022.116634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022]
Abstract
Most patients with osteopetrosis (OPT) can be causally and curatively treated with allogeneic hematopoietic stem cell transplantation (HSCT) because osteoclasts are derived from the HSC. However, HSCT is contraindicated in some forms of OPT, namely OPT with neurodegeneration (in all patients with OSTM1 and about half of patients with CLCN7 mutations) and OPT caused by an osteoblast defect (patients with RANKL mutations). HSCT for OPT risks serious side effects, such as transplant failure, venous occlusive disease, pulmonary hypertension, and hypercalcemic crises. Nevertheless, the success rate of HSCT has improved significantly in recent decades. This applies, in particular, to HSCT from non-HLA compatible (haploidentical) donors. Therefore, nowadays an HSCT can be discussed for intermediate OPT forms. After a successful HSCT, most patients have very good quality of life, but about two-thirds are visually impaired, and in rarer cases show motor and neurological disabilities. Early diagnosis, further improvements in transplantation procedures, and advances to improve quality-of-life after transplantation are challenges for the future.
Collapse
Affiliation(s)
- Ansgar Schulz
- Department of Paediatrics, University Medical Center Ulm, Eythstr. 24, D 89075 Ulm, Germany.
| | - Despina Moshous
- Department of Pediatric Immunology, Hematology and Rheumatology, Hôpital Universitaire Necker-Enfants Malades, AP-HP, Université Paris Cité, 149, rue de Sèvres, 75015 Paris, France.
| |
Collapse
|
4
|
Huybrechts Y, Van Hul W. Osteopetrosis associated with PLEKHM1 and SNX10 genes, both involved in osteoclast vesicular trafficking. Bone 2022; 164:116520. [PMID: 35981699 DOI: 10.1016/j.bone.2022.116520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 11/24/2022]
Abstract
The clinical and radiological variability seen in different forms of osteopetrosis, all due to impaired osteoclastic bone resorption, reflect many causal genes. Both defective differentiation of osteoclasts from hematopoietic stem cells as well as disturbed functioning of osteoclasts can be the underlying pathogenic mechanism. Pathogenic variants in PLEKHM1 and SNX10 can be classified among the latter as they impair vesicular transport within the osteoclast and therefore result in the absence of a ruffled border. Some of the typical radiological hallmarks of osteopetrosis can be seen, and most cases present as a relatively mild form segregating in an autosomal recessive mode of inheritance.
Collapse
Affiliation(s)
- Yentl Huybrechts
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium
| | - Wim Van Hul
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| |
Collapse
|
5
|
Elson A, Stein M, Rabie G, Barnea-Zohar M, Winograd-Katz S, Reuven N, Shalev M, Sekeres J, Kanaan M, Tuckermann J, Geiger B. Sorting Nexin 10 as a Key Regulator of Membrane Trafficking in Bone-Resorbing Osteoclasts: Lessons Learned From Osteopetrosis. Front Cell Dev Biol 2021; 9:671210. [PMID: 34095139 PMCID: PMC8173195 DOI: 10.3389/fcell.2021.671210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/23/2021] [Indexed: 12/30/2022] Open
Abstract
Bone homeostasis is a complex, multi-step process, which is based primarily on a tightly orchestrated interplay between bone formation and bone resorption that is executed by osteoblasts and osteoclasts (OCLs), respectively. The essential physiological balance between these cells is maintained and controlled at multiple levels, ranging from regulated gene expression to endocrine signals, yet the underlying cellular and molecular mechanisms are still poorly understood. One approach for deciphering the mechanisms that regulate bone homeostasis is the characterization of relevant pathological states in which this balance is disturbed. In this article we describe one such “error of nature,” namely the development of acute recessive osteopetrosis (ARO) in humans that is caused by mutations in sorting nexin 10 (SNX10) that affect OCL functioning. We hypothesize here that, by virtue of its specific roles in vesicular trafficking, SNX10 serves as a key selective regulator of the composition of diverse membrane compartments in OCLs, thereby affecting critical processes in the sequence of events that link the plasma membrane with formation of the ruffled border and with extracellular acidification. As a result, SNX10 determines multiple features of these cells either directly or, as in regulation of cell-cell fusion, indirectly. This hypothesis is further supported by the similarities between the cellular defects observed in OCLs form various models of ARO, induced by mutations in SNX10 and in other genes, which suggest that mutations in the known ARO-associated genes act by disrupting the same plasma membrane-to-ruffled border axis, albeit to different degrees. In this article, we describe the population genetics and spread of the original arginine-to-glutamine mutation at position 51 (R51Q) in SNX10 in the Palestinian community. We further review recent studies, conducted in animal and cellular model systems, that highlight the essential roles of SNX10 in critical membrane functions in OCLs, and discuss possible future research directions that are needed for challenging or substantiating our hypothesis.
Collapse
Affiliation(s)
- Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Merle Stein
- Institute of Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Grace Rabie
- Hereditary Research Laboratory and Department of Life Sciences, Bethlehem University, Bethlehem, Palestine
| | - Maayan Barnea-Zohar
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | | | - Nina Reuven
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Moran Shalev
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Juraj Sekeres
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Moien Kanaan
- Hereditary Research Laboratory and Department of Life Sciences, Bethlehem University, Bethlehem, Palestine
| | - Jan Tuckermann
- Institute of Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Benjamin Geiger
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|