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Molecular Genetics and Metabolism Feb 2014The mucopolysaccharidoses (MPS), a group of rare genetic disorders caused by defects in glycosaminoglycan (GAG) catabolism, are progressive, multi-systemic diseases with... (Review)
Review
The mucopolysaccharidoses (MPS), a group of rare genetic disorders caused by defects in glycosaminoglycan (GAG) catabolism, are progressive, multi-systemic diseases with a high burden of morbidity. Enzyme replacement therapy (ERT) is available for MPS I, II, and VI, and may improve walking ability, endurance, and pulmonary function as evidenced by data from pivotal trials and extension studies. Despite these demonstrable benefits, cardiac valve disease, joint disease, and skeletal disease, all of which cause significant morbidity, do not generally improve with ERT if pathological changes are already established. Airway disease improves, but usually does not normalize. These limitations can be well understood by considering the varied functions of GAG in the body. Disruption of GAG catabolism has far-reaching effects due to the triggering of secondary pathogenic cascades. It appears that many of the consequences of these secondary pathogenic events, while they may improve on treatment, cannot be fully corrected even with long-term exposure to enzyme, thereby supporting the treatment of patients with MPS before the onset of clinical disease. This review examines the data from clinical trials and other studies in human patients to explore the limits of ERT as currently used, then discusses the pathophysiology, fetal tissue studies, animal studies, and sibling reports to explore the question of how early to treat an MPS patient with a firm diagnosis. The review is followed by an expert opinion on the rationale for and the benefits of early treatment.
Topics: Child, Preschool; Clinical Trials as Topic; Dysostoses; Enzyme Replacement Therapy; Glycosaminoglycans; Heart Valves; Humans; Iduronate Sulfatase; Joints; Mucopolysaccharidoses; N-Acetylgalactosamine-4-Sulfatase; Recombinant Proteins; Respiratory System; Secondary Prevention
PubMed: 24388732
DOI: 10.1016/j.ymgme.2013.11.015 -
Current Topics in Developmental Biology 2014Hes genes, encoding basic helix-loop-helix (HLH) transcriptional repressors, are mammalian homologues of Drosophila hairy and Enhancer of split genes, both of which are... (Review)
Review
Hes genes, encoding basic helix-loop-helix (HLH) transcriptional repressors, are mammalian homologues of Drosophila hairy and Enhancer of split genes, both of which are required for normal neurogenesis in Drosophila. There are seven members in the human Hes family, Hes1-7, which are expressed in many tissues and play various roles mainly in development. All Hes proteins have three conserved domains: basic HLH (bHLH), Orange, and WRPW domains. The basic region binds to target DNA sequences, while the HLH region forms homo- and heterodimers with other bHLH proteins, the Orange domain is responsible for the selection of partners during heterodimer formation, and the WRPW domain recruits corepressors. Hes1, Hes5, and Hes7 are known as downstream effectors of canonical Notch signaling, which regulates cell differentiation via cell-cell interaction. Hes factors regulate many events in development by repressing the expression of target genes, many of which encode transcriptional activators that promote cell differentiation. For example, Hes1, Hes3, and Hes5 are highly expressed by neural stem cells, and inactivation of these genes results in insufficient maintenance of stem cell proliferation and prematurely promotes neuronal differentiation. Recently, it was shown that the expression dynamics of Hes1 plays crucial roles in proper developmental timings and fate-determination steps of embryonic stem cells and neural progenitor cells. Here, we discuss some key features of Hes factors in development and diseases.
Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Brain; Cell Differentiation; Cell Proliferation; Cells, Cultured; Central Nervous System; DNA-Binding Proteins; Dysostoses; Embryonic Stem Cells; Gene Expression Regulation, Developmental; Homeodomain Proteins; Humans; Mice; Multigene Family; Ribs; Scoliosis; Spine; Transcription Factor HES-1; Transcription Factors
PubMed: 25248479
DOI: 10.1016/B978-0-12-405943-6.00007-5 -
European Journal of Human Genetics :... Jun 2023In some cases of infants with apparently isolated single-suture synostosis, an underlying variant can be found. We aimed to determine the molecular substratum in...
In some cases of infants with apparently isolated single-suture synostosis, an underlying variant can be found. We aimed to determine the molecular substratum in isolated sagittal and metopic craniosynostosis. To this end, we included all infants who presented isolated midline synostosis (sagittal or metopic) and had undergone surgery at the craniosynostosis national reference center of Lyon University Hospital. All infants were examined by a multidisciplinary team including neurosurgeons, clinical geneticists and neuropsychologist. Among 101 infants tested, 13 carried a total of 13 variants; that is, 12.9% of the infants carried a variant in genes known to be involved in craniosynostosis. Seven infants carried SMAD6 variants, 2 in FGFR2, 1 in TWIST1, one in FREM1, one in ALX4 and one in TCF12. All variants were detected at the heterozygous level in genes associated with autosomal dominant craniosynostosis. Also, neurodevelopmental testing showed especially delayed acquisition of language in children with than without variants in SMAD6. In conclusion, a high percentage of young children with isolated midline craniosynostosis, especially in isolated trigonocephaly, carried SMAD6 variants. The interpretation of the pathogenicity of the genes must take into account incomplete penetrance, usually observed in craniosynostosis. Our results highlight the interest of molecular analysis in the context of isolated sagittal and/or metopic craniosynostosis to enhance an understanding of the pathophysiology of midline craniosynostosis.
Topics: Child; Infant; Humans; Child, Preschool; Craniosynostoses
PubMed: 36732661
DOI: 10.1038/s41431-023-01295-y -
BMJ Case Reports Mar 2022The management of patients with Apert syndrome (AS) is complex and reflects the multisystem disease as a result of premature fusion of cranial vault, cranial base and...
The management of patients with Apert syndrome (AS) is complex and reflects the multisystem disease as a result of premature fusion of cranial vault, cranial base and midface sutures as well as extremity anomalies characterised by syndactyly. Early cranial sutural fusion results in craniocerebral disproportion which can lead to crisis surgical intervention due to raised intracranial pressure, ophthalmic and compromised airway concerns. Childhood inventions are often determined by psychosocial concerns and adult surgical interventions are often determined by cosmetic concerns. Treatments are provided by many different specialists within multidisciplinary teams (MDT). The treatment pathway extends from birth well into adulthood and is often associated with a heavy burden of care. Due to the extensive nature of the interaction with these patients MDT members have opportunities to provide enhanced patient-centred care and support.This case report provides an overview of the current knowledge of the aetiology of AS, illustrates the pathway of surgical and non-surgical management of AS and provides a long-term review of the dentofacial treatment outcomes.By having a better understanding of the impact of AS and treatment provided, MDT members can not only provide improved clinical treatment but also offer improved patient experiences for those with craniofacial anomalies, in particular, an increased awareness of the psychosocial challenges they endure.
Topics: Acrocephalosyndactylia; Adult; Child; Cranial Sutures; Craniofacial Abnormalities; Face; Humans; Skull Base
PubMed: 35236672
DOI: 10.1136/bcr-2021-245224 -
Science Progress 2023The purpose of this meta-analysis was to strengthen the credibility of primary research results by combining open-source scientific material, namely a comparison of... (Meta-Analysis)
Meta-Analysis Review
The purpose of this meta-analysis was to strengthen the credibility of primary research results by combining open-source scientific material, namely a comparison of craniofacial features (Cfc) between Crouzon's syndrome (CS) patients and non-CS populations. All articles published up to October 7, 2021, were included in the search of PubMed, Google Scholar, Scopus, Medline, and Web of Science. The PRISMA guidelines were followed to conduct this study. PECO framework was applied in the following ways: Those who have CS are denoted by the letter P, those who have been diagnosed with CS via clinical or genetic means by the letter E, those who do not have CS by the letter C, and those who have a Cfc of CS by the letter O. Independent reviewers collected the data and ranked the publications based on their adherence to the Newcastle-Ottawa Quality Assessment Scale. A total of six case-control studies were reviewed for this meta-analysis. Due to the large variation in cephalometric measures, only those published in at least two previous studies were included. This analysis found that CS patients had a smaller skull and mandible volumes than those without CS.in terms of SNA° (MD = -2.33, = <0.001, = 83.6%) and ANB°(MD = -1.89, = <0.005, = 93.1%)), as well as ANS (MD = -1.87, = 0.001, = 96.5%)) and SN/PP (MD = -1.99, = 0.036, = 77.3%)). In comparison to the general population, people with CS tend to have shorter and flatter cranial bases, smaller orbital volumes, and cleft palates. They differ from the general population in having a shorter skull base and more V-shaped maxillary arches.
Topics: Humans; Craniofacial Dysostosis; Case-Control Studies
PubMed: 36803068
DOI: 10.1177/00368504231156297 -
Journal of Medical Genetics Sep 1993
Review
Topics: Abnormalities, Multiple; Craniofacial Dysostosis; Female; Fingers; Genetic Variation; Humans; Infant; Phenotype; Radius; Syndrome; Synostosis; Thumb
PubMed: 8411075
DOI: 10.1136/jmg.30.9.779 -
Orphanet Journal of Rare Diseases May 2022The formation of the digits is a tightly regulated process. During embryogenesis, disturbance of genetic pathways in limb development could result in syndactyly; a... (Review)
Review
The formation of the digits is a tightly regulated process. During embryogenesis, disturbance of genetic pathways in limb development could result in syndactyly; a common congenital malformation consisting of webbing in adjacent digits. Currently, there is a paucity of knowledge regarding the exact developmental mechanism leading to this condition. The best studied canonical interactions of Wingless-type-Bone Morphogenic Protein-Fibroblast Growth Factor (WNT-BMP-FGF8), plays a role in the interdigital cell death (ICD) which is thought to be repressed in human syndactyly. Animal studies have displayed other pathways such as the Notch signaling, metalloprotease and non-canonical WNT-Planar cell polarity (PCP), to also contribute to failure of ICD, although less prominence has been given. The current diagnosis is based on a clinical evaluation followed by radiography when indicated, and surgical release of digits at 6 months of age is recommended. This review discusses the interactions repressing ICD in syndactyly, and characterizes genes associated with non-syndromic and selected syndromes involving syndactyly, according to the best studied canonical WNT-BMP-FGF interactions in humans. Additionally, the controversies regarding the current syndactyly classification and the effect of non-coding elements are evaluated, which to our knowledge has not been previously highlighted. The aim of the review is to better understand the developmental process leading to this condition.
Topics: Animals; Extremities; Fibroblast Growth Factors; Humans; Signal Transduction; Syndactyly
PubMed: 35549993
DOI: 10.1186/s13023-022-02339-0 -
Cerebral Cortex (New York, N.Y. : 1991) Mar 2023Recent trio-based whole-exome sequencing studies of congenital hydrocephalus and nonsyndromic craniosynostosis have identified multiple novel disease genes that have...
Recent trio-based whole-exome sequencing studies of congenital hydrocephalus and nonsyndromic craniosynostosis have identified multiple novel disease genes that have illuminated the pathogenesis of these disorders and shed new insight into the genetic regulation of human brain and skull development. Continued study of these and other historically understudied developmental anomalies has the potential to replace the current antiquated, anatomically based disease classification systems with a molecular nomenclature that may increase precision for genetic counseling, prognostication, and surgical treatment stratification-including when not to operate. Data will also inform future clinical trials, catalyze the development of targeted therapies, and generate infrastructure and publicly available data sets relevant for other related nonsurgical neurodevelopmental and neuropsychiatric diseases.
Topics: Humans; Skull; Craniosynostoses; Forecasting; Molecular Biology
PubMed: 35739418
DOI: 10.1093/cercor/bhac249 -
The International Journal of... Jun 2009Treacher Collins syndrome (TCS) is a rare congenital birth disorder characterized by severe craniofacial defects. The syndrome is associated with mutations in the TCOF1... (Review)
Review
Treacher Collins syndrome (TCS) is a rare congenital birth disorder characterized by severe craniofacial defects. The syndrome is associated with mutations in the TCOF1 gene which encodes a putative nucleolar phosphoprotein known as treacle. An animal model of the severe form of TCS, generated through mutation of the mouse homologue Tcof1 has recently revealed significant insights into the etiology and pathogenesis of TCS (Dixon and Dixon, 2004; Dixon et al., 2006; Jones et al 2008). During early embryogenesis in a TCS individual, an excessive degree of neuroepithelial apoptosis diminishes the generation of neural crest cells. Neural crest cells are a migratory stem and progenitor cell population that generates most of the tissues of the head including much of the bone, cartilage and connective tissue. It has been hypothesized that mutations in Tcof1 disrupt ribosome biogenesis to a degree that is insufficient to meet the proliferative needs of the neuroepithelium and neural crest cells. This causes nucleolar stress activation of the p53-dependent apoptotic pathway which induces neuroepithelial cell death. Interestingly however, chemical and genetic inhibition of p53 activity can block the wave of apoptosis and prevent craniofacial anomalies in Tcof1 mutant mice [Jones NC, Lynn ML, Gaudenz K, Sakai D, Aoto K, Rey JP, et al. Prevention of the neurocristopathy Treacher Collins syndrome through inhibition of p53 function. Nat Med 2008;14:125-33]. These findings shed new light on potential therapeutic avenues for the prevention of not only TCS but also other congenital craniofacial disorders which share a similar etiology and pathogenesis.
Topics: Animals; Humans; Intracellular Signaling Peptides and Proteins; Mandibulofacial Dysostosis; Mice; Nuclear Proteins; Phosphoproteins
PubMed: 19027870
DOI: 10.1016/j.biocel.2008.10.026 -
Developmental Dynamics : An Official... Jun 2007Abnormal vertebral segmentation (AVS) in man is a relatively common congenital malformation but cannot be subjected to the scientific analysis that is applied in animal... (Review)
Review
Abnormal vertebral segmentation (AVS) in man is a relatively common congenital malformation but cannot be subjected to the scientific analysis that is applied in animal models. Nevertheless, some spectacular advances in the cell biology and molecular genetics of somitogenesis in animal models have proved to be directly relevant to human disease. Some advances in our understanding have come through DNA linkage analysis in families demonstrating a clustering of AVS cases, as well as adopting a candidate gene approach. Only rarely do AVS phenotypes follow clear Mendelian inheritance, but three genes-DLL3, MESP2, and LNFG-have now been identified for spondylocostal dysostosis (SCD). SCD is characterized by extensive hemivertebrae, trunkal shortening, and abnormally aligned ribs with points of fusion. In familial cases clearly following a Mendelian pattern, autosomal recessive inheritance is more common than autosomal dominant and the genes identified are functional within the Notch signaling pathway. Other genes within the pathway cause diverse phenotypes such as Alagille syndrome (AGS) and CADASIL, conditions that may have their origin in defective vasculogenesis. Here, we deal mainly with SCD and AGS, and present a new classification system for AVS phenotypes, for which, hitherto, the terminology has been inconsistent and confusing.
Topics: Animals; Disease Susceptibility; Dysostoses; Humans; Phenotype; Receptors, Notch; Signal Transduction; Spine
PubMed: 17497699
DOI: 10.1002/dvdy.21182