Morquio A Syndrome: Identification of Differential Patterns of Molecular Pathway Interactions in Bone Lesions.

Mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome) is a rare autosomal recessive lysosomal storage disease (LSD) caused by deficiency of a hydrolase enzyme, N-acetylgalactosamine-6-sulfate sulfatase, and characterized clinically by mainly musculoskeletal manifestations. The mechanisms underlying bone involvement in humans are typically explored using invasive techniques such as bone biopsy, which complicates analysis in humans. We compared bone proteomes using DDA and SWATH-MS in wild-type and MPS IVA knockout mice (UNT) to obtain mechanistic information about the disease. Our findings reveal over 1000 dysregulated proteins in knockout mice, including those implicated in oxidative phosphorylation, oxidative stress (reactive oxygen species), DNA damage, and iron transport, and suggest that lactate dehydrogenase may constitute a useful prognostic and follow-up biomarker. Identifying biomarkers that reflect MPS IVA clinical course, severity, and progression have important implications for disease management.

Evidence of epigenetic landscape shifts in mucopolysaccharidosis IIIB and IVA.

Lysosomal storage diseases (LSDs) are a group of monogenic diseases characterized by mutations in genes coding for proteins associated with the lysosomal function. Despite the monogenic nature, LSDs patients exhibit variable and heterogeneous clinical manifestations, prompting investigations into epigenetic factors underlying this phenotypic diversity. In this study, we focused on the potential role of epigenetic mechanisms in the pathogenesis of mucopolysaccharidosis IIIB (MPS IIIB) and mucopolysaccharidosis IVA (MPS IVA). We analyzed DNA methylation (5mC) and histone modifications (H3K14 acetylation and H3K9 trimethylation) in MPS IIIB and MPS IVA patients' fibroblasts and healthy controls. The findings revealed that global DNA hypomethylation is present in cell lines for both diseases. At the same time, histone acetylation was increased in MPS IIIB and MPS IVA cells in a donor-dependent way, further indicating a shift towards relaxed open chromatin in these MPS. Finally, the constitutive heterochromatin marker, histone H3K9 trimethylation, only showed reduced clustering in MPS IIIB cells, suggesting limited alterations in heterochromatin organization. These findings collectively emphasize the significance of epigenetic mechanisms in modulating the phenotypic variations observed in LSDs. While global DNA hypomethylation could contribute to the MPS pathogenesis, the study also highlights individual-specific epigenetic responses that might contribute to phenotypic heterogeneity. Further research into the specific genes and pathways affected by these epigenetic changes could provide insights into potential therapeutic interventions for these MPS and other LSDs.

Comprehensive Preventive and Therapeutic Oral Health Care: A Case Report of Mucopolysaccharidosis Type IV A in a Pediatric Patient.

Mucopolysaccharidosis (MPS) is a metabolic disorder resulting from a deficiency of lysosomal enzymes. It is an autosomal recessive disorder with similar incidences in men and women. Mucopolysaccharidosis type IV A is caused by a deficiency of N-acetylgalactosamine-6-sulfatase, which deficiency is, in turn, caused by alterations in the GALNS gene. It is marked by a short stature, a pigeon chest, frontal bossing, kyphosis, and a flat nasal bridge. Intraorally, macroglossia, hypodontia, dentinogenesis imperfecta, a broad mouth, and an anterior open bite are some of the common features. The present paper reports on a case of MPS in a 5-year-old male patient, along with providing a review of the literature and insight into the oral manifestations related to MPS IV A, also called Morquio A syndrome, and its dental treatment. It aims to highlight the clinical recommendations for oral health care in such cases during different phases of MPS IV A treatment.

Mucopolysaccharidosis IVA: Current Disease Models and Drawbacks.

Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) encoding gene. GALNS leads to the lysosomal degradation of the glycosaminoglyccreasans keratan sulfate and chondroitin 6-sulfate. Impaired GALNS enzymes result in skeletal and non-skeletal complications in patients. For years, the MPS IVA pathogenesis and the assessment of promising drugs have been evaluated using in vitro (primarily fibroblasts) and in vivo (mainly mouse) models. Even though value information has been raised from those studies, these models have several limitations. For instance, chondrocytes have been well recognized as primary cells affected in MPS IVA and responsible for displaying bone development impairment in MPS IVA patients; nonetheless, only a few investigations have used those cells to evaluate basic and applied concepts. Likewise, current animal models are extensively represented by mice lacking GALNS expression; however, it is well known that MPS IVA mice do not recapitulate the skeletal dysplasia observed in humans, making some comparisons difficult. This manuscript reviews the current in vitro and in vivo MPS IVA models and their drawbacks.

Specific heterozygous variants in MGP lead to endoplasmic reticulum stress and cause spondyloepiphyseal dysplasia.

Matrix Gla protein (MGP) is a vitamin K-dependent post-translationally modified protein, highly expressed in vascular and cartilaginous tissues. It is a potent inhibitor of extracellular matrix mineralization. Biallelic loss-of-function variants in the MGP gene cause Keutel syndrome, an autosomal recessive disorder characterized by widespread calcification of various cartilaginous tissues and skeletal and vascular anomalies. In this study, we report four individuals from two unrelated families with two heterozygous variants in MGP, both altering the cysteine 19 residue to phenylalanine or tyrosine. These individuals present with a spondyloepiphyseal skeletal dysplasia characterized by short stature with a short trunk, diffuse platyspondyly, midface retrusion, progressive epiphyseal anomalies and brachytelephalangism. We investigated the cellular and molecular effects of one of the heterozygous deleterious variants (C19F) using both cell and genetically modified mouse models. Heterozygous 'knock-in' mice expressing C19F MGP recapitulate most of the skeletal anomalies observed in the affected individuals. Our results suggest that the main underlying mechanism leading to the observed skeletal dysplasia is endoplasmic reticulum stress-induced apoptosis of the growth plate chondrocytes. Overall, our findings support that heterozygous variants in MGP altering the Cys19 residue cause autosomal dominant spondyloepiphyseal dysplasia, a condition distinct from Keutel syndrome both clinically and molecularly.

Tracheal Narrowing and Its Impact on Anesthesia Care in Patients With Morquio A (Mucopolysaccharidosis Type IVA): An Observational Study.

BACKGROUND: Recently, tracheal narrowing has been recognized as a significant comorbid condition in patients with Morquio A, also known as mucopolysaccharidosis IVA. We studied a large cohort of patients with Morquio A to describe the extent of their tracheal narrowing and its relationship to airway management during anesthesia care. METHODS: This is an observational study, collecting data retrospectively, of a cohort of patients with Morquio A. Ninety-two patients with Morquio A syndrome were enrolled, among whom 44 patients had their airway evaluated by computed tomography angiography and had undergone an anesthetic within a year of the evaluation. Our hypothesis was that the tracheal narrowing as evaluated by computed tomography angiography increases with age in patients with Morquio A. The primary aim of the study was to examine the degree of tracheal narrowing in patients with Morquio A and describe the difficulties encountered during airway management, thus increasing awareness of both the tracheal narrowing and airway management difficulties in this patient population. In addition, the degree of tracheal narrowing was evaluated for its association with age or spirometry parameters using Spearman's rank correlation. Analysis of variance followed by the Bonferroni test was used to further examine the age-based differences in tracheal narrowing for the 3 age groups: 1 to 10 years, 11 to 20 years, and >21 years. RESULTS: Patient age showed a positive correlation with tracheal narrowing ( rs= 0.415; 95% confidence interval [95% CI], 0.138-0.691; P = .005) with older patients having greater narrowing of the trachea. Among spirometry parameters, FEF25%-75% showed an inverse correlation with tracheal narrowing as follows: FEF25%-75% versus tracheal narrowing: ( rs = -0.467; 95% CI, -0.877 to -0.057; P = .007). During anesthetic care, significant airway management difficulties were encountered, including cancelation of surgical procedures, awake intubation using flexible bronchoscope, and failed video laryngoscopy attempts. CONCLUSIONS: Clinically significant tracheal narrowing was present in patients with Morquio A, and the degree of such narrowing likely contributed to the difficulty with airway management during their anesthetic care. Tracheal narrowing worsens with age, but the progression appears to slow down after 20 years of age. In addition to tracheal narrowing, spirometry values of FEF25%-75% may be helpful in the overall evaluation of the airway in patients with Morquio A.

The development of a broad-spectrum retaining ß-exo-galactosidase activity-based probe.

Acid ß-galactosidase (GLB1) and galactocerebrosidase (GALC) are retaining exo-ß-galactosidases involved in lysosomal glycoconjugate metabolism. Deficiency of GLB1 may result in the lysosomal storage disorders GM1 gangliosidosis, Morquio B syndrome, and galactosialidosis, and deficiency of GALC may result in Krabbe disease. Activity-based protein profiling (ABPP) is a powerful technique to assess the activity of retaining glycosidases in relation to health and disease. This work describes the use of fluorescent and biotin-carrying activity-based probes (ABPs) to assess the activity of both GLB1 and GALC in cell lysates, culture media, and tissue extracts. The reported ABPs, which complement the growing list of retaining glycosidase ABPs based on configurational isomers of cyclophellitol, should assist in fundamental and clinical research on various ß-galactosidases, whose inherited deficiencies cause debilitating lysosomal storage disorders.

Enhanced Efficiency of the Basal and Induced Apoptosis Process in Mucopolysaccharidosis IVA and IVB Human Fibroblasts.

Morquio disease, also called mucopolysaccharidosis IV (MPS IV), belongs to the group of lysosomal storage diseases (LSD). Due to deficiencies in the activities of galactose-6-sulfate sulfatase (in type A) or ß-galactosidase (in type B), arising from mutations in GALNS or GLB1, respectively, keratan sulfate (one of glycosaminoglycans, GAGs) cannot be degraded efficiently and accumulates in lysosomes. This primary defect leads to many cellular dysfunctions which then cause specific disease symptoms. Recent works have indicated that different secondary effects of GAG accumulation might significantly contribute to the pathomechanisms of MPS. Apoptosis is among the cellular processes that were discovered to be affected in MPS cells on the basis of transcriptomic studies and some cell biology experiments. However, Morquio disease is the MPS type which is the least studied in light of apoptosis dysregulation, while RNA-seq analyses suggested considerable changes in the expression of genes involved in apoptosis in MPS IVA and IVB fibroblasts. Here we demonstrate that cytochrome c release from mitochondria is more efficient in MPS IVA and IVB fibroblasts relative to control cells, both under the standard cultivation conditions and after treatment with staurosporine, an apoptosis inducer. This indication of apoptosis stimulation was corroborated by measurements of the levels of caspases 9, 3, 6, and 7, as well as PARP, cleaved at specific sites, in Morquio disease and control fibroblasts. The more detailed analyses of the transcriptomic data revealed which genes related to apoptosis are down- and up-regulated in MPS IVA and IVB fibroblasts. We conclude that apoptosis is stimulated in Morquio disease under both standard cell culture conditions and after induction with staurosporine which may contribute to the pathomechanism of this disorder. Dysregulation of apoptosis in other MPS types is discussed.

Generation of two iPSC lines from patient with Mucopolysaccharidosis IV B type and autosomal recessive non-syndromic hearing loss 12.

We generated two human induced pluripotency stem cell (hiPSC) lines, RCMGi011-A and 11-B, from skin fibroblast from patient with Mucopolysaccharidosis IV B type and autosomal recessive non-syndromic hearing loss 12 using non-integrating, viral CytoTune™-iPS 2.0 Sendai Reprogramming Kit. We verified variant c.808 T > G and insertion in GLB1 gene, as well as two mutations, c.6992 T > C and c.805C > T, in CDH23 gene which lead to autosomal recessive hearing loss type 12. We have demonstrated normal karyotype of hiPSCs and capacity for cell differentiation into three germ layers.

[Clinical characteristics of 111 cases with mucopolysaccharidosis â £A].

Objective: To analyze the clinical characteristics of patients with Mucopolysaccharidosis ⅣA (MPS ⅣA). Methods: A retrospective study was conducted on 111 patients with MPS ⅣA in Xinhua Hospital of Shanghai Jiao Tong University School of Medcine from December 2008 to August 2020, confirmed by enzyme activity and genetic testing. General situation, clinical manifestations and enzyme activity test results were analyzed. According to the clinical manifestations, it can be divided into severe, intermediate and mild group. The independent sample t test was used to compare the birth body length and weight of children with that of normal boys and girls, and group comparisons of enzyme activities were evaluated by median test. Results: One hundred and eleven unrelated patients, 69 males and 42 females, were classified into 3 subtypes: severe (n=85), intermediate (n=14), and mild (n=12). The age at symptom onset were 1.6 (1.0, 3.0) years, and at diagnosis were 4.3 (2.8, 7.8) years. Skeletal manifestations were observed in all patients and consisted mainly of pectus carinatum (96/111, 86.5%), motor dysfunction (78/111, 70.3%), spinal deformity (71/111, 64.0%), growth retardation (64/111, 57.7%), joint laxity (63/111, 56.8%) and genu valgum (62/111, 55.9%). Eighty-eight patients (88/111, 79.3%) with MPS ⅣA were also along with non-skeletal manifestations, mainly including snoring (38/111, 34.2%), coarse faces (34/111, 30.6%), and visual impairment (26/111, 23.4%). The most common skeletal manifestation was pectus carinatum (79 cases), and non-skeletal manifestation was snoring (30 cases) and coarse faces (30 cases) in severe patients, pectus carinatum (13 cases) and snoring (5 cases) in intermediate type, motor dysfunction (11 cases) and snoring (3 cases) and visual impairment (3 cases) in mild patients. The height and weight of severe patients began to fall below -2 s at 2-<5 years and 5-<7 years, respectively. At the age of 10-<15 years, the standard deviation score of the height of severe patients reached (-6.2±1.6) s in males and (-6.4±1.2) s in females, and the score of weight got (-3.0±1.1) s in males and (-3.5±0.5) s in females. The height of intermediate patients began to fall below -2 s at the age of 7-<10 years, and the standard deviation score of height were -4.6 s and -3.6 s in 2 males, and -4.6 s and -3.8 s in 2 females at the age of 10-<15 years. The weight remained within -2 s in 72.0% (18/25) of intermediate patients compared to age-matched healthy children. In the mild patients with MPS ⅣA, the mean standard deviation score of height and weight was within -2 s. The enzyme activities of mild patients (2.02 (1.05, 8.20) nmol/(17 h·mg)) were both significantly higher than that of intermediate (0.57 (0.47, 0.94) nmol/(17 h·mg)) and severe (0.22 (0, 0.59) nmol/(17 h·mg)) patients (Z=9.91, 13.98, P=0.005, 0.001), and the enzyme activity of intermediate patients was significantly higher than that of severe patients (Z=8.56, P=0.010). Conclusions: The clinical manifestations of MPS ⅣA are charactered by pectus carinatum, motor function impairment, spinal deformity and growth retardation. The clinical characteristics, growth rate and enzyme activity differ among the 3 subtypes of MPS ⅣA.

Bone Growth Induction in Mucopolysaccharidosis IVA Mouse.

Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is caused by a deficiency of the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) enzyme, leading to the accumulation of glycosaminoglycans (GAG), keratan sulfate (KS) and chondroitin-6-sulfate (C6S), mainly in cartilage and bone. This lysosomal storage disorder (LSD) is characterized by severe systemic skeletal dysplasia. To this date, none of the treatment options for the MPS IVA patients correct bone pathology. Enzyme replacement therapy with elosulfase alpha provides a limited impact on bone growth and skeletal lesions in MPS IVA patients. To improve bone pathology, we propose a novel gene therapy with a small peptide as a growth-promoting agent for MPS IVA. A small molecule in this peptide family has been found to exert biological actions over the cardiovascular system. This work shows that an AAV vector expressing a C-type natriuretic (CNP) peptide induces bone growth in the MPS IVA mouse model. Histopathological analysis showed the induction of chondrocyte proliferation. CNP peptide also changed the pattern of GAG levels in bone and liver. These results suggest the potential for CNP peptide to be used as a treatment in MPS IVA patients.

Posterior Atlantoaxial Fusion With C1-2 Pedicle Screw Fixation for Atlantoaxial Dislocation in Pediatric Patients With Mucopolysaccharidosis IVA (Morquio a Syndrome): A Case Series.

OBJECTIVE: To investigate the efficacy and safety of posterior atlantoaxial fusion (AAF) with C1-2 pedicle screw fixation for atlantoaxial dislocation (AAD) in pediatric patients with mucopolysaccharidosis IVA (MPS IVA). METHODS: This study included 21 pediatric patients with MPS IVA who underwent posterior AAF with C1-2 pedicle screw fixation. Anatomical parameters of the C1 and C2 pedicle were measured on preoperative computed tomography (CT). The American Spinal Injury Association (ASIA) scale was used to evaluate the neurological status. The fusion and accuracy of pedicle screw was assessed on postoperative CT. Demographic, radiation dose, bone density, surgical, and clinical data were recorded. RESULTS: Patients reviewed included 21 patients younger than 16 years with an average age of 7.4 ± 4.2 years and an average of 20.9 ± 7.7 months follow-up. Fixation of 83 C1 and C2 pedicle screws was performed successfully and 96.3% of them were identified as being safe. One patient developed postoperative transient disturbance of consciousness and one developed fetal airway obstruction and died about 1 month after the surgery. Out of the remaining20 patients, fusion was achieved, symptoms were improved, and no other serious surgical complications were observed at the latest follow-up. CONCLUSIONS: Posterior AAF with C1-2 pedicle screw fixation is effective and safe for AAD in pediatric patients with MPS IVA. However, the procedure is technically demanding and should be performed by experienced surgeons with strict multidisciplinary consultations.

Analysis of urinary oligosaccharide excretion patterns by UHPLC/HRAM mass spectrometry for screening of lysosomal storage disorders.

Oligosaccharidoses, sphingolipidoses and mucolipidoses are lysosomal storage disorders (LSDs) in which defective breakdown of glycan-side chains of glycosylated proteins and glycolipids leads to the accumulation of incompletely degraded oligosaccharides within lysosomes. In metabolic laboratories, these disorders are commonly diagnosed by thin-layer chromatography (TLC) but more recently also mass spectrometry-based approaches have been published. To expand the possibilities to screen for these diseases, we developed an ultra-high-performance liquid chromatography (UHPLC) with a high-resolution accurate mass (HRAM) mass spectrometry (MS) screening platform, together with an open-source iterative bioinformatics pipeline. This pipeline generates comprehensive biomarker profiles and allows for extensive quality control (QC) monitoring. Using this platform, we were able to identify α-mannosidosis, ß-mannosidosis, α-N-acetylgalactosaminidase deficiency, sialidosis, galactosialidosis, fucosidosis, aspartylglucosaminuria, GM1 gangliosidosis, GM2 gangliosidosis (M. Sandhoff) and mucolipidosis II/III in patient samples. Aberrant urinary oligosaccharide excretions were also detected for other disorders, including NGLY1 congenital disorder of deglycosylation, sialic acid storage disease, MPS type IV B and GSD II (Pompe disease). For the latter disorder, we identified heptahexose (Hex7), as a potential urinary biomarker, in addition to glucose tetrasaccharide (Glc4), for the diagnosis and monitoring of young onset cases of Pompe disease. Occasionally, so-called "neonate" biomarker profiles were observed in young patients, which were probably due to nutrition. Our UHPLC/HRAM-MS screening platform can easily be adopted in biochemical laboratories and allows for simple and robust screening and straightforward interpretation of the screening results to detect disorders in which aberrant oligosaccharides accumulate.

An adolescent case of sellar osteochondromyxoma in the setting of spondyloepiphyseal dysplasia.

PURPOSE: Osteochondromyxomas (OMX) are rare congenital bone tumors that have only been described in the context of Carney complex syndrome (CNC). Data on OMX as a separate entity and in association with other disorders remain limited, making both diagnosis and treatment difficult. METHODS: A case report of a 17-year-old female diagnosed with sellar OMX is presented in the setting of spondyloepiphyseal dysplasia (SED). We discuss the radiographic and histopathological interpretations in addition to reviewing the current literature on OMX. RESULTS: A successful gross total resection of the tumor was achieved via an endonasal endoscopic transsphenoidal approach. A diagnosis was established radiographically and pathologically. CONCLUSION: The diagnosis and treatment of OMX are best achieved via tissue biopsy. Following confirmed osteochondromyxoma cases long term for recurrence and outcomes will be essential in understanding its natural tumor history and in establishing standard treatments.

Inflammatory process and oxidative/nitrative stress: in vivo study in mucopolysaccharidosis type IV A patients under long-term enzyme replacement therapy.

Mucopolysaccharidosis type IV A (MPS IVA) is an inborn error of the metabolism (IEM) caused by a deficiency of the enzyme N-acetylgalactosamine 6-sulfate sulfatase (GALNS). Since 2014, enzyme replacement therapy (ERT) is the recommended treatment for these patients. It is known that the inflammatory response is closely related to antioxidant defenses and oxidative stress, and literature shows involvement of oxidative stress in the pathogenesis of IEM. The aim of this study is to investigate the mechanisms of oxidative/nitrative stress and inflammation in patients with MPS IVA under long-term ERT. In the present work we investigate parameters of oxidative/nitrative stress in plasma and urine of MPS IVA patients under long-term ERT and controls, such as plasmatic nitrate/nitrite levels using the LDH Method, urinary di-tyrosine levels by fluorometric method, plasmatic content of sulfhydryl groups, urinary oxidized guanine species by ELISA kit and the plasmatic total antioxidant status. We next evaluated the plasmatic pro and anti-inflammatory cytokines concentration (IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α) and the expression of factors and enzymes Nrf-2, NF-κß and HO-1, main mediators between inflammation and oxidative stress. In concern to the oxidative/nitrative stress parameters, there was no significant difference between the groups MPS IVA patients under long-term ERT and controls, showing that there is no overproducing of RNS, no protein damage, no DNA/RNA oxidative damage and no modification in the non-enzymatic antioxidant capacity of a tissue to prevent the damage associated to free radical processes in these patients. It was also verified no significant difference between the MPS IVA patients under long-term ERT and controls groups regarding the production of proinflammatory cytokines. About anti-inflammatory cytokines, IL 10 was shown to be elevated in MPS IVA patients under long-term ERT in comparison to the control group. We next evaluated the genic expression of Nrf-2, NF-κß and HO-1and there was no significant difference between the MPS IVA patients under long-term ERT and control groups. In conclusion, MPS IVA patients under long term ERT are not in an inflammatory state and there is no alteration in genic expression in the genes analyzed which are involved in oxidative stress and inflammatory pathways. It is,however, important to consider that absence of imbalance of antioxidant defenses in MPS IVA patients under long term ERT is so far preliminary it is supported by methodologies that are not highly sensitive nor very accurate. Further experiments in future using state-of-the-art methodologies will corroborate these findings. Nevertheless, our results demonstrated the protective effect of the treatment in relation to the parameters studied and the importance of starting treatment in the early stages of the disease.

A pictorial review of the radiographic skeletal findings in Morquio syndrome (mucopolysaccharidosis type IV).

Morquio syndrome, also known as Morquio-Brailsford syndrome or mucopolysaccharidosis type IV (MPS IV), is a subgroup of mucopolysaccharidosis. It is an autosomal recessive lysosomal storage disorder. Two subtypes of Morquio syndrome have been identified. In MPS IVA, a deficiency in N-acetylgalactosamine-6-sulfate sulfatase interrupts the normal metabolic pathway of degrading glycosaminoglycans. Accumulated undigested glycosaminoglycans in the tissue and bones result in complications leading to severe skeletal deformity. In MPS IVB, a deficiency in beta-galactosidase results in a milder phenotype than in MPS IVA. Morquio syndrome presents a variety of clinical manifestations in a spectrum of mild to severe. It classically has been considered a skeletal dysplasia with significant skeletal involvement. However, the extraskeletal features can also provide valuable information to guide further work-up to assess the possibility of the disorder. Although the disease involves almost all parts of the body, it most commonly affects the axial skeleton, specifically the vertebrae. The characteristic radiologic findings in MPS IV, such as paddle-shaped ribs, odontoid hypoplasia, vertebral deformity, metaphyseal and epiphyseal bone dysplasia, and steep acetabula, are encompassed in the term "dysostosis multiplex," which is a common feature among other types of MPS and storage disorders. Myelopathy due to spinal cord compression and respiratory airway obstruction are the most critical complications related to mortality and morbidity. The variety of clinical features, as well as overlapping of radiological findings with other disorders, make diagnosis challenging, and delays in diagnosis and treatment may lead to critical complications. Timely imaging and radiologic expertise are important components for diagnosis. Gene therapies may provide robust treatment, particularly if genetic variations can be screened in utero.

Efficient CRISPR/Cas9 nickase-mediated genome editing in an in vitro model of mucopolysaccharidosis IVA.

Mucopolysaccharidosis IVA (MPS IVA) is a lysosomal storage disorder (LSD) caused by mutations in gene encoding for GALNS enzyme. Lack of GALNS activity leads to the accumulation of glycosaminoglycans (GAGs) keratan sulfate and chondroitin 6-sulfate. Although enzyme replacement therapy has been approved since 2014 for MPS IVA, still there is an unmet medical need to have improved therapies for this disorder. CRISPR/Cas9-based gene therapy has been tested for several LSDs with encouraging findings, but to date it has not been assayed on MPS IVA. In this work, we validated for the first time the use of CRISPR/Cas9, using a Cas9 nickase, for the knock-in of an expression cassette containing GALNS cDNA in an in vitro model of MPS IVA. The results showed the successful homologous recombination of the expression cassette into the AAVS1 locus, as well as a long-term increase in GALNS activity reaching up to 40% of wild-type levels. We also observed normalization of lysosomal mass, total GAGs, and oxidative stress, which are some of the major findings regarding the pathophysiological events in MPS IVA. These results represent a proof-of-concept of the use of CRISPR/Cas9 nickase strategy for the development of a novel therapeutic alternative for MPS IVA.

How did intraoperative neuromonitorization prevent tetraplegia?

PURPOSE: Patients with mucopolysaccharidosis type IVA (MPS IVA) have many risk factors for myelopathy and paresis. These are spinal cord compression, bone stenosis, and soft tissue thickening with ligament laxity, deformity, odontoid hypoplasia, and atlantoaxial instability. Although most patients with MPS IVA appear generally healthy at birth, patients often show skeletal deformities within a few years. Surgical indications are difficult to determine. Historically, many physicians have used prophylactic decompression and fusion in young, asymptomatic MPS IVA patients to prevent cord compression. Although spinal cord decompression is usually required at the craniocervical junction in patients with MPS IVA, decompression may be required at other spinal cord levels as well. There is a risk of developing neurological damage during surgery. The most common causes are ischemia secondary to cardiac output deteriorated in the prone position or due to artery damage, and local trauma due to neck movements or traction while bringing the patient to the prone position. Neurophysiological monitoring is very important during surgery to reduce the risk of neurological damage in spinal cord surgery. In this case report, a case with loss of lower extremity neuromonitorization motor evoked potential (MEP) responses in the early period of surgery without any intervention to the craniocervical junction after prone positioning will be presented.

Clinical characteristics of 111 cases with mucopolysaccharidosis ⅣA / 中华儿科杂志

Objective: To analyze the clinical characteristics of patients with Mucopolysaccharidosis ⅣA (MPS ⅣA). Methods: A retrospective study was conducted on 111 patients with MPS ⅣA in Xinhua Hospital of Shanghai Jiao Tong University School of Medcine from December 2008 to August 2020, confirmed by enzyme activity and genetic testing. General situation, clinical manifestations and enzyme activity test results were analyzed. According to the clinical manifestations, it can be divided into severe, intermediate and mild group. The independent sample t test was used to compare the birth body length and weight of children with that of normal boys and girls, and group comparisons of enzyme activities were evaluated by median test. Results: One hundred and eleven unrelated patients, 69 males and 42 females, were classified into 3 subtypes: severe (n=85), intermediate (n=14), and mild (n=12). The age at symptom onset were 1.6 (1.0, 3.0) years, and at diagnosis were 4.3 (2.8, 7.8) years. Skeletal manifestations were observed in all patients and consisted mainly of pectus carinatum (96/111, 86.5%), motor dysfunction (78/111, 70.3%), spinal deformity (71/111, 64.0%), growth retardation (64/111, 57.7%), joint laxity (63/111, 56.8%) and genu valgum (62/111, 55.9%). Eighty-eight patients (88/111, 79.3%) with MPS ⅣA were also along with non-skeletal manifestations, mainly including snoring (38/111, 34.2%), coarse faces (34/111, 30.6%), and visual impairment (26/111, 23.4%). The most common skeletal manifestation was pectus carinatum (79 cases), and non-skeletal manifestation was snoring (30 cases) and coarse faces (30 cases) in severe patients, pectus carinatum (13 cases) and snoring (5 cases) in intermediate type, motor dysfunction (11 cases) and snoring (3 cases) and visual impairment (3 cases) in mild patients. The height and weight of severe patients began to fall below -2 s at 2-<5 years and 5-<7 years, respectively. At the age of 10-<15 years, the standard deviation score of the height of severe patients reached (-6.2±1.6) s in males and (-6.4±1.2) s in females, and the score of weight got (-3.0±1.1) s in males and (-3.5±0.5) s in females. The height of intermediate patients began to fall below -2 s at the age of 7-<10 years, and the standard deviation score of height were -4.6 s and -3.6 s in 2 males, and -4.6 s and -3.8 s in 2 females at the age of 10-<15 years. The weight remained within -2 s in 72.0% (18/25) of intermediate patients compared to age-matched healthy children. In the mild patients with MPS ⅣA, the mean standard deviation score of height and weight was within -2 s. The enzyme activities of mild patients (2.02 (1.05, 8.20) nmol/(17 h·mg)) were both significantly higher than that of intermediate (0.57 (0.47, 0.94) nmol/(17 h·mg)) and severe (0.22 (0, 0.59) nmol/(17 h·mg)) patients (Z=9.91, 13.98, P=0.005, 0.001), and the enzyme activity of intermediate patients was significantly higher than that of severe patients (Z=8.56, P=0.010). Conclusions: The clinical manifestations of MPS ⅣA are charactered by pectus carinatum, motor function impairment, spinal deformity and growth retardation. The clinical characteristics, growth rate and enzyme activity differ among the 3 subtypes of MPS ⅣA.