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International Journal of Molecular... Apr 2021Bone development is a tightly regulated process. Several integrated signaling pathways including HH, PTHrP, WNT, NOTCH, TGF-β, BMP, FGF and the transcription factors... (Review)
Review
Bone development is a tightly regulated process. Several integrated signaling pathways including HH, PTHrP, WNT, NOTCH, TGF-β, BMP, FGF and the transcription factors SOX9, RUNX2 and OSX are essential for proper skeletal development. Misregulation of these signaling pathways can cause a large spectrum of congenital conditions categorized as skeletal dysplasia. Since the signaling pathways involved in skeletal dysplasia interact at multiple levels and have a different role depending on the time of action (early or late in chondrogenesis and osteoblastogenesis), it is still difficult to precisely explain the physiopathological mechanisms of skeletal disorders. However, in recent years, significant progress has been made in elucidating the mechanisms of these signaling pathways and genotype-phenotype correlations have helped to elucidate their role in skeletogenesis. Here, we review the principal signaling pathways involved in bone development and their associated skeletal dysplasia.
Topics: Animals; Bone Development; Humans; Osteochondrodysplasias; Signal Transduction
PubMed: 33919228
DOI: 10.3390/ijms22094321 -
American Journal of Physiology. Cell... Aug 2022The extracellular matrix is an intricate and essential network of proteins and nonproteinaceous components that provide a conducive microenvironment for cells to... (Review)
Review
The extracellular matrix is an intricate and essential network of proteins and nonproteinaceous components that provide a conducive microenvironment for cells to regulate cell function, differentiation, and survival. Fibronectin is one key component in the extracellular matrix that participates in determining cell fate and function crucial for normal vertebrate development. Fibronectin undergoes time-dependent expression patterns during stem cell differentiation, providing a unique stem cell niche. Mutations in fibronectin have been recently identified to cause a rare form of skeletal dysplasia with scoliosis and abnormal growth plates. Even though fibronectin has been extensively analyzed in developmental processes, the functional role and importance of this protein and its various isoforms in skeletal development remain less understood. This review attempts to provide a concise and critical overview of the role of fibronectin isoforms in cartilage and bone physiology and associated pathologies. This will facilitate a better understanding of the possible mechanisms through which fibronectin exerts its regulatory role on cellular differentiation during skeletal development. The review discusses the consequences of mutations in fibronectin leading to corner fracture type spondylometaphyseal dysplasia and presents a new outlook toward matrix-mediated molecular pathways in relation to therapeutic and clinical relevance.
Topics: Cell Differentiation; Extracellular Matrix; Fibronectins; Humans; Osteochondrodysplasias; Protein Isoforms
PubMed: 35759430
DOI: 10.1152/ajpcell.00226.2022 -
Molecular Genetics and Metabolism Feb 2015Patients with mucopolysaccharidoses (MPS) have accumulation of glycosaminoglycans in multiple tissues which may cause coarse facial features, mental retardation,... (Review)
Review
Patients with mucopolysaccharidoses (MPS) have accumulation of glycosaminoglycans in multiple tissues which may cause coarse facial features, mental retardation, recurrent ear and nose infections, inguinal and umbilical hernias, hepatosplenomegaly, and skeletal deformities. Clinical features related to bone lesions may include marked short stature, cervical stenosis, pectus carinatum, small lungs, joint rigidity (but laxity for MPS IV), kyphoscoliosis, lumbar gibbus, and genu valgum. Patients with MPS are often wheelchair-bound and physical handicaps increase with age as a result of progressive skeletal dysplasia, abnormal joint mobility, and osteoarthritis, leading to 1) stenosis of the upper cervical region, 2) restrictive small lung, 3) hip dysplasia, 4) restriction of joint movement, and 5) surgical complications. Patients often need multiple orthopedic procedures including cervical decompression and fusion, carpal tunnel release, hip reconstruction and replacement, and femoral or tibial osteotomy through their lifetime. Current measures to intervene in bone disease progression are not perfect and palliative, and improved therapies are urgently required. Enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), and gene therapy are available or in development for some types of MPS. Delivery of sufficient enzyme to bone, especially avascular cartilage, to prevent or ameliorate the devastating skeletal dysplasias remains an unmet challenge. The use of an anti-inflammatory drug is also under clinical study. Therapies should start at a very early stage prior to irreversible bone lesion, and damage since the severity of skeletal dysplasia is associated with level of activity during daily life. This review illustrates a current overview of therapies and their impact for bone lesions in MPS including ERT, HSCT, gene therapy, and anti-inflammatory drugs.
Topics: Animals; Anti-Inflammatory Agents; Bone Diseases; Bone and Bones; Chondrocytes; Disease Progression; Enzyme Replacement Therapy; Genetic Therapy; Hematopoietic Stem Cell Transplantation; Humans; Mucopolysaccharidoses
PubMed: 25537451
DOI: 10.1016/j.ymgme.2014.12.001 -
AACE Clinical Case Reports 2020To present a case of pyknodysostosis (PKND), a rare genetic cause of skeletal dysplasia that often goes undiagnosed even in patients with classic features.
OBJECTIVE
To present a case of pyknodysostosis (PKND), a rare genetic cause of skeletal dysplasia that often goes undiagnosed even in patients with classic features.
METHODS
We report a case of PKND that went undiagnosed over many years despite classic features. We performed physical examination, imaging studies, and genetic testing on the patient.
RESULTS
A 21-year-old female presented to endocrinology to establish care. On evaluation, she was noted to have disproportionate short stature and a past medical history notable for bilateral blindness due to optic atrophy secondary to bone enlargement and thickening of the optic nerve canal before age 7 years. She also had a history of foot fractures occurring with ambulation. Her family history was significant for consanguineous parents and relatives with similar clinical features. Physical examination revealed a short, 128-cm tall female with open anterior and mastoid fontanels, mild frontal bossing and micrognathia, evidence of double rows of teeth, and digits of varied length in both hands and feet. Plain radiographs demonstrated diffuse sclerosis and marked cortical thickening of the pelvis, femurs, metacarpals, proximal phalanges, and metatarsals as well as decreased phalangeal length and acro-osteolysis of the hands and feet. Dual energy X-ray absorptiometry demonstrated increased bone mineral density ( scores +2.5 lumbar spine, +3.7 femoral neck, +4.5 total hip). Genetic testing revealed a exon 5-homozygous mutation in the cathepsin K () gene consistent with PKND.
CONCLUSION
Patients with PKND come to medical attention for a variety of reasons but often go undiagnosed even when presenting with classic features due to the rarity of the condition and the overlap with other skeletal dysplasias.
PubMed: 32984533
DOI: 10.4158/ACCR-2020-0169 -
Frontiers in Endocrinology 2020Skeletal dysplasias are a diverse group of heritable diseases affecting bone and cartilage growth. Throughout the years, the molecular defect underlying many of the... (Review)
Review
Skeletal dysplasias are a diverse group of heritable diseases affecting bone and cartilage growth. Throughout the years, the molecular defect underlying many of the diseases has been identified. These identifications led to novel insights in the mechanisms regulating bone and cartilage growth and homeostasis. One of the pathways that is clearly important during skeletal development and bone homeostasis is the Wingless and int-1 (WNT) signaling pathway. So far, three different WNT signaling pathways have been described, which are all activated by binding of the WNT ligands to the Frizzled (FZD) receptors. In this review, we discuss the skeletal disorders that are included in the latest nosology of skeletal disorders and that are caused by genetic defects involving the WNT signaling pathway. The number of skeletal disorders caused by defects in WNT signaling genes and the clinical phenotype associated with these disorders illustrate the importance of the WNT signaling pathway during skeletal development as well as later on in life to maintain bone mass. The knowledge gained through the identification of the genes underlying these monogenic conditions is used for the identification of novel therapeutic targets. For example, the genes underlying disorders with altered bone mass are all involved in the canonical WNT signaling pathway. Consequently, targeting this pathway is one of the major strategies to increase bone mass in patients with osteoporosis. In addition to increasing the insights in the pathways regulating skeletal development and bone homeostasis, knowledge of rare skeletal dysplasias can also be used to predict possible adverse effects of these novel drug targets. Therefore, this review gives an overview of the skeletal and extra-skeletal phenotype of the different skeletal disorders linked to the WNT signaling pathway.
Topics: Animals; Bone Diseases; Bone and Bones; Genetic Diseases, Inborn; Humans; Musculoskeletal Abnormalities; Wnt Signaling Pathway
PubMed: 32328030
DOI: 10.3389/fendo.2020.00165 -
Annals of Pediatric Endocrinology &... Jun 2022Skeletal dysplasia is a diverse group of disorders that affect bone development and morphology. Currently, approximately 461 different genetic skeletal disorders have...
Skeletal dysplasia is a diverse group of disorders that affect bone development and morphology. Currently, approximately 461 different genetic skeletal disorders have been identified, with over 430 causative genes. Among these, fibroblast growth factor receptor 3 (FGFR3)-related skeletal dysplasia is a relatively common subgroup of skeletal dysplasia. Pediatric endocrinologists may encounter a suspected case of skeletal dysplasia in their practice, especially when evaluating children with short stature. Early and accurate diagnosis of FGFR3-related skeletal dysplasia is essential for timely management of complications and genetic counseling. This review summarizes 5 representative and distinct entities of skeletal dysplasia caused by pathogenic variants in FGFR3 and discusses emerging therapies for FGFR3-related skeletal dysplasias.
PubMed: 35793999
DOI: 10.6065/apem.2244114.057 -
Nutrients Mar 2015Sulphate is an obligate nutrient for healthy growth and development. Sulphate conjugation (sulphonation) of proteoglycans maintains the structure and function of... (Review)
Review
Sulphate is an obligate nutrient for healthy growth and development. Sulphate conjugation (sulphonation) of proteoglycans maintains the structure and function of tissues. Sulphonation also regulates the bioactivity of steroids, thyroid hormone, bile acids, catecholamines and cholecystokinin, and detoxifies certain xenobiotics and pharmacological drugs. In adults and children, sulphate is obtained from the diet and from the intracellular metabolism of sulphur-containing amino acids. Dietary sulphate intake can vary greatly and is dependent on the type of food consumed and source of drinking water. Once ingested, sulphate is absorbed into circulation where its level is maintained at approximately 300 μmol/L, making sulphate the fourth most abundant anion in plasma. In pregnant women, circulating sulphate concentrations increase by twofold with levels peaking in late gestation. This increased sulphataemia, which is mediated by up-regulation of sulphate reabsorption in the maternal kidneys, provides a reservoir of sulphate to meet the gestational needs of the developing foetus. The foetus has negligible capacity to generate sulphate and thereby, is completely reliant on sulphate supply from the maternal circulation. Maternal hyposulphataemia leads to foetal sulphate deficiency and late gestational foetal death in mice. In humans, reduced sulphonation capacity has been linked to skeletal dysplasias, ranging from the mildest form, multiple epiphyseal dysplasia, to achondrogenesis Type IB, which results in severe skeletal underdevelopment and death in utero or shortly after birth. Despite being essential for numerous cellular and metabolic functions, the nutrient sulphate is largely unappreciated in clinical settings. This article will review the physiological roles and regulation of sulphate during pregnancy, with a particular focus on animal models of disturbed sulphate homeostasis and links to human pathophysiology.
Topics: Amino Acids, Sulfur; Animals; Deficiency Diseases; Diet; Female; Fetal Development; Humans; Pregnancy; Pregnancy Complications; Prenatal Nutritional Physiological Phenomena; Sulfates
PubMed: 25746011
DOI: 10.3390/nu7031594 -
Developmental Dynamics : An Official... Mar 2021For the vast majority of the 6000 known rare disease the pathogenic mechanisms are poorly defined and there is little treatment, leading to poor quality of life and high... (Review)
Review
For the vast majority of the 6000 known rare disease the pathogenic mechanisms are poorly defined and there is little treatment, leading to poor quality of life and high healthcare costs. Genetic skeletal diseases (skeletal dysplasias) are archetypal examples of rare diseases that are chronically debilitating, often life-threatening and for which no treatments are currently available. There are more than 450 unique phenotypes that, although individually rare, have an overall prevalence of at least 1 per 4000 children. Multiple epiphyseal dysplasia (MED) is a clinically and genetically heterogeneous disorder characterized by disproportionate short stature, joint pain, and early-onset osteoarthritis. MED is caused by mutations in the genes encoding important cartilage extracellular matrix proteins, enzymes, and transporter proteins. Recently, through the use of various cell and mouse models, disease mechanisms underlying this diverse phenotypic spectrum are starting to be elucidated. For example, ER stress induced as a consequence of retained misfolded mutant proteins has emerged as a unifying disease mechanisms for several forms of MED in particular and skeletal dysplasia in general. Moreover, targeting ER stress through drug repurposing has become an attractive therapeutic avenue.
Topics: Endoplasmic Reticulum Stress; Extracellular Matrix Proteins; Humans; Mutation; Osteochondrodysplasias; Quality of Life
PubMed: 32633442
DOI: 10.1002/dvdy.221