Mucopolysaccharidoses Patients Research Articles

Is Ultrasonography a Reliable Approach for the Evaluation of Carpal Tunnel Syndrome in Patients With Mucopolysaccharidosis?

BackgroundOne of the most common causes of carpal tunnel syndrome (CTS) in childhood is mucopolysaccharidosis (MPS). While ultrasonography (US) can aid in the diagnosis of CTS in adult patients, there is limited experience of this in the pediatric group. We aimed to investigate the results of wrist ultrasonography, which may be a candidate alternative to electrophysiological examination. MethodsThe participants were evaluated for symptoms, physical examination findings, electrophysiological tests and grayscale US. CTS was diagnosed in accordance with the American Academy of Orthopedic Surgeons Management of Carpal Tunnel Syndrome: Evidence-Based Clinical Practice Guideline. ResultsIncluded in the study were 27 MPS patients aged 4.5–32 years and 30 healthy control subjects aged 4.3–26 years. Of the 54 wrists in the MPS group, 30 were diagnosed with CTS. The median cross-sectional area (CSA) at the proximal carpal tunnel, the CSA at the forearm, and the wrist-forearm ratio (WFR) were higher in the wrists of the MPS with CTS group than in those without CTS and the healthy control subjects. The WFR cutoff of ≥1.35, 56.6% (95% CI: 437.4–74.5) sensitivity, and 89.8% (95% CI: 81.0–95.5) specificity were consistent with a diagnosis of CTS (receiver operating characteristics analysis, area under the curve = 0.775, 95% CI: 0.673–0.877). ConclusionAlthough the US provides results with unsatisfactory specificity and sensitivity, it is a candidate for further investigation for the diagnosis of CTS because it is an innovative, noninvasive, and more accessible method. WFR value may produce more meaningful results than wrist or forearm nerve area measurements.

Humanistic burden of mucopolysaccharidoses: a systematic literature review

Objective To systematically review the literature and summarize the health-related quality-of-life (HRQoL) of patients undergoing treatment for mucopolysaccharidoses (MPS), a rare, hereditary lysosomal storage disorder. Methods A systematic review was performed in accordance with PRISMA guidelines to identify research studies that describe the humanistic burden of MPS. A comprehensive literature search was conducted in EMBASE, MEDLINE, and eligible conferences were screened to include applicable abstracts. Results Of 870 identified articles, 15 studies reported the HRQoL burden of patients with MPS undergoing or with a history of ERT and/or HSCT. These studies include patients of MPS I (n = 2), MPS II (n = 4), MPS IV (n = 6), MPS VI (n = 1), and subtype not mentioned (n = 2). Although the quality-of-life of MPS patients is influenced by time of diagnosis, pain, cognitive involvement, severity of disease, mobility, dependence, and time of treatment initiation, the HRQoL scores of MPS patients across all the scales were below the median reference population scores across all dimensions. This is seen in comparison to healthy participants but also in comparison to patients with other chronic illnesses. The multi-organ involvement, neurological impairment, pain, and morbidity associated with the condition not only affects activity of daily living but also affects social functioning, emotional status, employment status among adults, and school functioning among children. Conclusions This systematic literature review revealed the substantial humanistic burden of individuals affected by MPS as well as caregivers. Significant variation in HRQoL scores was observed, however studies indicate that the quality-of-life of MPS patients is influenced primarily by severity of disease (MPS type and phenotype), and then by time of diagnosis, pain, cognitive involvement, mobility, dependence, and time of treatment initiation. Further studies are needed to assess the global humanistic burden of MPS, particularly in MPS III, VI, VII, and IX subtypes, in adults, and for a longer follow-up period. Considering the vast array of HRQoL assessment tools available and used in this study, researchers should also consider using scales with condition-specific measures to ensure appropriate estimates of effectiveness.

Cardiac Involvement in Pediatric Mucopolysaccharidoses Patients and their Genetic Profile: A Retrospective Single-center Study

Abstract Background: Mucopolysaccharidoses (MPS) are rare metabolic disorders of monogenic inheritance, with varying degrees of cardiac involvement due to undegraded glycosaminoglycans getting aggregated in the spongiosa of the cardiac valves, the myocardium, and myointima of the coronary arteries. This study is an effort to understand the cardiac involvement and genetic pattern of pediatric MPS patients at a tertiary care center in South India. Methods: This descriptive study was done by examining records in our hospital database for MPS patients in the age group of 0–15 years, diagnosed between January 2014 and January 2023. Of these patients, 37 patients with echocardiographic loops available in the hospital system were reevaluated by a single pediatric cardiologist to avoid observer bias. The underlying genetic spectrum was also reviewed. Results: The cohort comprised 67.5% of males and a median age of 9.8 years (interquartile range: 6.5–14.9 years) with a distribution of 37.8% MPS I, 32.4% MPS II, 13.5% MPS IV, and 10.8% MPS VI. Early cardiac involvement in the form of valvar thickening, predominantly left sided (mitral [92%] >aortic [38%]), was seen across all MPS subtypes. We also noted an increased involvement of the tricuspid valve (38%) in our cohort. Moderate–severe valvar involvement was seen in 16% of the cohort, mostly MPS I, II, and VI patients, and more in the second half of the age group (>6 years), suggesting an age-associated worsening of cardiac lesions. Genetic analysis done in 68% of the cohort detected 61% of pathogenic variants, with a predominance of missense mutation (43%). However, no genotype–cardiac phenotype correlation could be ascertained. Conclusions: We identified a high proportion of cardiac abnormalities in our pediatric MPS cohort, which ranged from isolated valvar thickening to a more severe clinical picture, including moderate-to-severe valvular insufficiency and/or stenosis and left ventricular hypertrophy. Cardiac pathology is an early manifestation and a known cause of mortality in many MPS subtypes. Echocardiography is a key diagnostic technique for early detection, careful monitoring, and guidance in the initiation of a timely intervention that will help curb its progression. Hence, the need arises to raise awareness among the primary caretakers of this subset of patients on the need for early cardiac evaluation with a detailed echocardiography.

Specific GAG ratios in the diagnosis of mucopolysaccharidoses.

Mucopolysaccharidoses (MPS) screening is tedious and still performed by analysis of total glycosaminoglycans (GAG) using 1,9-dimethylmethylene blue (DMB) photometric assay, although false positive and negative tests have been reported. Analysis of differentiated GAGs have been pursued classically by gel electrophoresis or more recently by quantitative LC-MS assays. Secondary elevations of GAGs have been reported in urinary tract infections (UTI). In this manuscript, we describe the diagnostic accuracy of urinary GAG measurements by LC-MS for MPS typing in 68 untreated MPS and mucolipidosis (ML) patients, 183 controls and 153 UTI samples. We report age-dependent reference values and cut-offs for chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS) and keratan sulfate (KS) and specific GAG ratios. The use of HS/DS ratio in combination to GAG concentrations normalized to creatinine improves the diagnostic accuracy in MPS type I, II, VI and VII. In total 15 samples classified to the wrong MPS type could be correctly assigned using HS/DS ratio. Increased KS/HS ratio in addition to increased KS improves discrimination of MPS type IV by excluding false positives. Some samples of UTI patients showed elevation of specific GAGs, mainly CS, KS and KS/HS ratio and could be misclassified as MPS type IV. Finally, DMB photometric assay performed in MPS and ML samples reveal four false negative tests (sensitivity of 94%). In conclusion, specific GAG ratios in complement to quantitative GAG values obtained by LC-MS enhance discrimination of MPS types. Exclusion of patients with UTI improve diagnostic accuracy in MPS IV but not in other types.

Quantification of Glycosaminoglycans Using Harmine Extract from Peganum harmala L. in Mucopolysaccharidoses Researches

Background: Harmine is used in the quantification of glycosaminoglycans (GAGs) for the research on mucopolysaccharidoses (MPSs). Although this product is commercially available, researchers may consider preparing it under laboratory conditions when it is unavailable for various reasons. This research aims to extract harmine from Peganum harmala L. seeds and determine whether this extract can be used as a substitute for pure harmine in the quantification of GAGs and, consequently, in the research on MPS. Methods: P. harmala L. seeds were obtained from the plant and extracted using methanol. The harmine extract was then used in a spectrophotometric assay on controls, including patients known of having MPS and healthy subjects and patients suspected of having different types of MPS. Results: One milligram of harmine extract in 1 ml of ethanol is sufficient to produce the chromogen as that obtained by pure harmine. The chromogen exhibits a peak absorbance peak at 510 nm. The concordance between the two forms of harmine reaches 100%, either for abnormal values seen in GAGs from MPS patients or for normal values in those from healthy controls. Suspicion of having MPS was lifted in investigated patients. The harmine extracted from P. harmala L. seeds allowed for accurate and reproducible quantification of the GAGs. Conclusion: This study demonstrates that harmine extract can be used as a reagent for the quantification of GAGs in the research on MPS when pure harmine is unavailable in the same way as pure harmine.

Long-term outcome of hematopoietic stem cell transplantation in two children with Mucopolysaccharidosis

To explore the long-term efficacy of allogeneic hematopoietic stem cell transplantation (alloHSCT) in patients with Mucopolysaccharidosis (MPS), which has rarely been reported in China. A 18-month-old boy and a 23-month-old girl undergoing alloHSCT for MPS VI and MPS IH Shanghai Children's Medical Center on March 30, 2006 and September 6, 2006 were selected as the study subjects. A busulfan-based myeloablative regimen was used as the conditioning regimen. Peripheral stem cells were respectively collected from a human leucocyte antigen (HLA) matched sibling carrier donor and a HLA 9/10 matched unrelated donor. Both patients were followed up for more than 15 years. The functions of internal organs before and after the transplantation were compared, and child 1 was also compared with his untreated brother and healthy brother. Both children have achieved full donor chimerism after the transplantation, and their enzymatic activities have remained stable. The enzymatic activity of the child 1 was slightly lower than normal but similar to that of his carrier donor, whilst that of the child 2 was normal. Both children have attended schools with good academic performance. Compared with his untreated brother, the respiratory function and hearing of child 1 have significantly improved. However, his orthopedic and cardiac disorders have still remained and required medical intervention. For child 2, her obstructive pulmonary disease was resolved and cognitive development was well preserved after the HSCT. Her heart disease has become stabilized and even improved with time, though her corneal clouding and skeletal malformation still required surgery. MPS patients can sustain long-term and stable enzymatic activities after successful alloHSCT. Compared with untreated patients, their health can be significantly improved, along with considerably prolonged survival, though the long-term efficacy of HSCT for different organs may vary to a certain extent.

Glycosaminoglycan-induced proinflammatory cytokine levels as disease marker in mucopolysaccharidosis

Recently, it has been shown disturbances in oxidant/antioxidant system and increases in some inflammatory markers in animal studies and in some Mucopolysaccharidoses (MPSs) patients. In this study, we aimed to determine the oxidative stress/antioxidant parameters and pro-inflammatory cytokine levels in the serum of MPS patients, in order to evaluate the possible role of inflammation in these patient groups regarding to accumulated metabolites.MPS I (n = 3), MPS II (n = 8), MPS III (n = 4), MPS IVA (n = 3), MPS VI (n = 3), and VII (n = 1) patients and 20 age-matched healthy subjects were included into the study.There was no statistically significant change in activities of SOD, Catalase, GSH-Px and lipid peroxidation levels in erythrocytes between the MPS patients and healthy controls. While IL-1alpha (p = 0.054), IL-6 (p = 0.008) levels, and chitotriosidase activity (p = 0.003) elevated in MPS3 patients, IL1α (p = 0.006), IL-1β (p = 0.006), IL-6 (p = 0.006), IFNγ (p = 0.006), and NFκB (p = 0.006) levels increased in MPS-6 patients.Elevated levels of IL-6, IL1α and chitotriosidase activity demonstrated macrophage activation in MPSIII untreated with enzyme replacement. Our study showed for the first time that high levels of IL1α, IL-6, IL1β and NFκB were present in MPSVI patients, demonstrating the induction of inflammation by dermatan sulphate. The low level of paraoxonase in MPSVI patients may be a good marker for cardiac involvement.Overall, this study provides important insights into the relationship between lysosomal storage of glycosaminoglycan and inflammation in MPS patients. It highlights possible pathways for the increased release of inflammatory molecules and suggests new targets for the development of treatments.

Evaluation of cardiac findings in mucopolysaccharidosis.

Mucopolysaccharidoses (MPS) are a group of rare genetic diseases and heart involvement is one of the important conflicts in most types, which may cause serious complications. We used M-Mode and two-dimensional speckle tracking echocardiography (2D-STE) to explore cardiovascular involvements in MPS patients. The present cross-sectional study investigated the frequency of cardiac involvements in MPS patients. Included participants were MPS types I, II, III, IV, and VI who underwent specialized echocardiography exams to assess valvular function, systolic and diastolic function, left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS). 35 patients were enrolled in this study. The total mean age of patients was 9.58 ± 5.11 years and 71.4% were male. Type IV (40%) and type III (31.4%) were the most frequent MPS. Although LVEF did not differ notably among MPS types, GLS was significantly different (p = 0.029). Mitral regurgitation was observed remarkably more in MPS type III (p = 0.001) while mitral stenosis was more common in type III (p = 0.007). There was a significant association between LVEF and GLS (β= -0.662; p = 0.025) and between LVEF and MPS type (β = 1.82; p = 0.025) when adjusted for GLS. Cardiac complications are very common and are one of the most important causes of death in MPS patients. 2D-STE seems to be superior to M-Mode for detection of early and subclinical cardiac dysfunction in MPS patients.

Adenotonsillar pathology in mucopolysaccharidoses - lysosomal storage predominates in paracortical CD63+ cells.

Despite the adenoids are regularly removed in patients with mucopolysaccharidoses (MPS), the underlying tissue and cellular pathologiesremain understudied. We characterized an (immuno)histopathologic and ultrastructural phenotype dominated by lysosomal storage changes in a specific subset of adenotonsillar paracortical cells in 8 MPS patients (3 MPS I, 3 MPS II, and 2 MPS IIIA). These abnormal cells were effectively detected by an antibody targeting the lysosomal membrane tetraspanin CD63. Important, CD63+ storage vacuoles in these cells lacked the monocytes/macrophages lysosomal marker CD68. Such a distinct patterning of CD63 and CD68 was not present in a patient with infantile neurovisceral variant of acid sphingomyelinase deficiency. The CD63+ storage pathology was absent in two MPS I patients who either received enzyme-replacement therapy or underwent hematopoietic stem cells transplantation prior the adenoidectomy. Our study demonstrates novel features of lysosomal storage patterning and suggests diagnostic utility of CD63 detection in adenotonsillar lymphoid tissue of MPS patients.

A glycomic workflow for LC–MS/MS analysis of urine glycosaminoglycan biomarkers in mucopolysaccharidoses

In recent years, several rational designed therapies have been developed for treatment of mucopolysaccharidoses (MPS), a group of inherited metabolic disorders in which glycosaminoglycans (GAGs) are accumulated in various tissues and organs. Thus, improved disease-specific biomarkers for diagnosis and monitoring treatment efficacy are of paramount importance. Specific non-reducing end GAG structures (GAG-NREs) have become promising biomarkers for MPS, as the compositions of the GAG-NREs depend on the nature of the lysosomal enzyme deficiency, thereby creating a specific pattern for each subgroup. However, there is yet no straightforward clinical laboratory platform which can assay all MPS-related GAG-NREs in one single analysis. Here, we developed and applied a GAG domain mapping approach for analyses of urine samples of ten MPS patients with various MPS diagnoses and corresponding aged-matched controls. We describe a nano-LC–MS/MS method of GAG-NRE profiling, utilizing 2-aminobenzamide reductive amination labeling to improve the sensitivity and the chromatographic resolution. Diagnostic urinary GAG-NREs were identified for MPS types IH/IS, II, IIIc, IVa and VI, corroborating GAG-NRE as biomarkers for these known enzyme deficiencies. Furthermore, a significant reduction of diagnostic urinary GAG-NREs in MPS IH (n = 2) and MPS VI (n = 1) patients under treatment was demonstrated. We argue that this straightforward glycomic workflow, designed for the clinical analysis of MPS-related GAG-NREs in one single analysis, will be of value for expanding the use of GAG-NREs as biomarkers for MPS diagnosis and treatment monitoring.

Leukocyte Imbalances in Mucopolysaccharidoses Patients.

Mucopolysaccharidoses (MPSs) are rare inherited lysosomal storage diseases (LSDs) caused by deficient activity in one of the enzymes responsible for glycosaminoglycans lysosomal degradation. MPS II is caused by pathogenic mutations in the IDS gene, leading to deficient activity of the enzyme iduronate-2-sulfatase, which causes dermatan and heparan sulfate storage in the lysosomes. In MPS VI, there is dermatan sulfate lysosomal accumulation due to pathogenic mutations in the ARSB gene, leading to arylsulfatase B deficiency. Alterations in the immune system of MPS mouse models have already been described, but data concerning MPSs patients is still scarce. Herein, we study different leukocyte populations in MPS II and VI disease patients. MPS VI, but not MPS II patients, have a decrease percentage of natural killer (NK) cells and monocytes when compared with controls. No alterations were identified in the percentage of T, invariant NKT, and B cells in both groups of MPS disease patients. However, we discovered alterations in the naïve versus memory status of both helper and cytotoxic T cells in MPS VI disease patients compared to control group. Indeed, MPS VI disease patients have a higher frequency of naïve T cells and, consequently, lower memory T cell frequency than control subjects. Altogether, these results reveal MPS VI disease-specific alterations in some leukocyte populations, suggesting that the type of substrate accumulated and/or enzyme deficiency in the lysosome may have a particular effect on the normal cellular composition of the immune system.

An Innovative Tool for Evidence-Based, Personalized Treatment Trials in Mucopolysaccharidosis.

Mucopolysaccharidosis (MPS) is a group of rare metabolic diseases associated with reduced life expectancy and a substantial unmet medical need. Immunomodulatory drugs could be a relevant treatment approach for MPS patients, although they are not licensed for this population. Therefore, we aim to provide evidence justifying fast access to innovative individual treatment trials (ITTs) with immunomodulators and a high-quality evaluation of drug effects by implementing a risk-benefit model for MPS. The iterative methodology of our developed decision analysis framework (DAF) consists of the following steps: (i) a comprehensive literature analysis on promising treatment targets and immunomodulators for MPS; (ii) a quantitative risk-benefit assessment (RBA) of selected molecules; and (iii) allocation phenotypic profiles and a quantitative assessment. These steps allow for the personalized use of the model and are in accordance with expert and patient representatives. The following four promising immunomodulators were identified: adalimumab, abatacept, anakinra, and cladribine. An improvement in mobility is most likely with adalimumab, while anakinra might be the treatment of choice for patients with neurocognitive involvement. Nevertheless, a RBA should always be completed on an individual basis. Our evidence-based DAF model for ITTs directly addresses the substantial unmet medical need in MPS and characterizes a first approach toward precision medicine with immunomodulatory drugs.

Adaptive skills in children with mucopolysaccharidoses

Introduction. Mucopolysaccharidoses (MPS) are a group of rare lethal lysosomal storage disoders. The progress in pathogenetic and symptomatic treatment, achieved in the last two decades, has resulted in increased life expectancy of patients. Assessment of functional abilities of patients is necessary for optimization of medical, psychological, and pedagogical support. 
 The aim of the study. To study the adaptive skills, measured with Vineland Adaptive Behavior Scales, and the impact of enzyme-replacement therapy on adaptive skills in MPS children.
 Materials and methods. A semi-structured interview for Vineland Adaptive Behavior Scales filling was carried out with one of the parents of 59 children with MPS. 41 patients had neuronopathic disease: 20 children received pathogenetic еnzyme replacement therapy (ERT), 21 patients didn’t receive ERT. 18 patients exhibited non-neuronopathic disease: 8 children received ERT, 10 — didn’t receive pathogenetic therapy. Dynamical changes in adaptive skills were investigated in 11 patients with neuronopathic MPS. 
 Results. Low level of adaptive motor, communication, daily living and socialization skills and their dynamical regress, stagnation or decele­ration are characteristic for children with neuronopathic MPS. More than 75% of non-neuronopathic MPS patients have moderately low and low levels of adaptive behavior composite. ERT hasn’t demonstrated significant impact on adaptive skills in MPS patients. Non-significant tendency toward better level of communication skills has been noticed in children, receiving pathogenetic therapy. Necessity of weekly infusion may have a negative influence on patients’ socialization. 
 Conclusion. Elaboration of motor, pedagogical, and social rehabilitation programs is needed for correction of deficiency in adaptive skills and achieving adequate social adaptation in MPS children with preserved cognitive abilities.

Identifying the genetic causes of phenotypically diagnosed Pakistani mucopolysaccharidoses patients by whole genome sequencing.

Background: Lysosomal storage disorders (LSDs) are a group of inherited metabolic diseases, which encompass more than 50 different subtypes of pathologies. These disorders are caused by defects in lysosomal enzymes, transporters, and other non-lysosomal proteins. Mucopolysaccharidosis (MPS) is the most common subgroup of lysosomal storage disorders in which the body is unable to properly breakdown mucopolysaccharides. The aim of the present study was to identify novel genes and pathogenic variants in families from diverse regions of Pakistan with clinically diagnosed mucopolysaccharidosis type I and mucopolysaccharidosis type II. Methods: Clinical diagnosis identified 12 with mucopolysaccharidosis I and 2 with mucopolysaccharidosis II in 14 families and whole genome sequencing (WGS) was performed to identify the causative variations in 15 affected individuals. Twenty-two unaffected individuals including parents or normal siblings of patients were also sequenced. Putative causal variants were identified by co-segregation and functional annotation. Results: Analysis of whole genome sequencing data revealed ten novel and six previously reported variants in lysosomal storage disorders-associated genes (IDUA, GALNS, SGSH, GAA, IDS, ALDOB, TRAPPC4, MASP1, SMARCAL, KIAA1109, HERC1, RRAS2) and a novel candidate gene (ABCA5) for lysosomal storage disorder-like phenotypes, which has previously been associated with symptoms strongly related with lysosomal storage disorder in animal models. Conclusion: Multigenic inheritance was found in several families highlighting the importance of searching for homozygous pathogenic variants in several genes also in families with a high degree of consanguinity.

The Interplay of Glycosaminoglycans and Cysteine Cathepsins in Mucopolysaccharidosis.

Mucopolysaccharidosis (MPS) consists of a group of inherited lysosomal storage disorders that are caused by a defect of certain enzymes that participate in the metabolism of glycosaminoglycans (GAGs). The abnormal accumulation of GAGs leads to progressive dysfunctions in various tissues and organs during childhood, contributing to premature death. As the current therapies are limited and inefficient, exploring the molecular mechanisms of the pathology is thus required to address the unmet needs of MPS patients to improve their quality of life. Lysosomal cysteine cathepsins are a family of proteases that play key roles in numerous physiological processes. Dysregulation of cysteine cathepsins expression and activity can be frequently observed in many human diseases, including MPS. This review summarizes the basic knowledge on MPS disorders and their current management and focuses on GAGs and cysteine cathepsins expression in MPS, as well their interplay, which may lead to the development of MPS-associated disorders.

Hip and Knee Arthroplasty in Patients with Mucopolysaccharidosis: A Systematic Review

Aims: To review the use of knee and hip arthroplasty for patients with mucopolysaccharidoses (MPS) to inform clinicians and patients of this emerging area of orthopaedic practice and direct future studies. Patients and Methods: An Embase database review was conducted according to Preferred Reporting Item for Systematic Reviews and Meta-analyses (PRISMA) guidelines to identify relevant published articles. Extracted information included demographic data, indications for surgery, surgical details, post-operative outcomes and complications. Results: Ten articles reported 15 patients with a total of 5 knee and 20 hip arthroplasties were identified and included. The mean age was 28.3 years and mean follow up duration for knee and hip arthroplasties was 3.6 years and 5.1 years respectively. Indications for surgery included pain in all patients, reduced range of motion, genu valgum and joint instability. Complex arthroplasty techniques were required including extensive soft tissue releases, instrumentation modification, screw fixation and modular/dysplasia arthroplasty components. There were four intra-operative fractures in hip arthroplasty patients and one hip arthroplasty underwent revision due to loosening. Pain resolution was documented for all knee arthroplasties and 90% of hip arthroplasties, whilst complications occurred in 9/20 (45%) of all arthroplasties. Conclusion: Arthroplasty surgery in this rare patient group can be successfully performed for pain relief and improvement in function with careful pre-operative planning and multidisciplinary management. Treating teams should be encouraged to share their experience to contribute to our understanding of indications, technique and outcomes for arthroplasty procedures in MPS patients.

How to Distinguish Attenuated Forms of Mucopolysaccharidosis and Articular Forms of Juvenile Arthritis: Development of Diagnostic Algorithm Based on the Data from Multicenter Retrospective Study

Background. Differential diagnosis of attenuated forms of mucopolysaccharidosis (MPS) and juvenile idiopathic arthritis (JIA) can be challenging due to their similarities.Objective. The aim of the study is to create simple diagnostic criteria (DScore) that would allow to differentiate MPS from JIA for earlier MPS diagnosis.Methods. The retrospective multicenter study included analysis of clinical (joint, heart, eye involvement, hearing loss, hernias, psychomotor delay, noisy breathing, posture disorders, macrocephaly, hepatomegaly, splenomegaly, and growth delay) and laboratory data (ESR, CRP, hemoglobin, WBC, and platelets) from MPS patients (n = 41) and from rheumatoid factor-negative polyarticular category of JIA patients (n = 255). These variables allowed to differentiate both conditions and were used to create DScore.Results. Patients with MPS had younger onset age, male predominance, height and weight delay, lower inflammation markers (WBC, platelets, and ESR), and usually involved joints, especially cervical spine, upper limbs joints, hip, and small foot joints. The prevalence of eye involvement was similar for both diseases, however, the type of involvement was different. JIA patients had uveitis and its’ complications and MPS patients — corneal opacity and cataract. No differences in CRP levels were revealed in most cases. The major diagnostic criterion of MPS was the presence of more than one extra-articular manifestation associated with polyarticular involvement. DScore has included 5 following criteria: ESR ≤ 11 mm/h (38 points), height ≤ -2.0 SD (20 points), onset age of articular manifestations ≤ 1.1 year (24 points), male gender (15 points), and symmetrical limitation of movements in elbow joints (29 points). The sum > 38 points allowed us to differentiate MPS and JIA with sensitivity of 92.7% and specificity of 91.0%.Conclusion. This DScore can be used for differential diagnosis of mild MPS and JIA alongside with routine diagnostic procedures. DScore allows us to identify a group of patients with joint involvement who require MPS exclusion.

Expression of Long Noncoding RNAs in Fibroblasts from Mucopolysaccharidosis Patients.

In this report, changes in the levels of various long non-coding RNAs (lncRNAs) were demonstrated for the first time in fibroblasts derived from patients suffering from 11 types/subtypes of mucopolysaccharidosis (MPS). Some kinds of lncRNA (SNHG5, LINC01705, LINC00856, CYTOR, MEG3, and GAS5) were present at especially elevated levels (an over six-fold change relative to the control cells) in several types of MPS. Some potential target genes for these lncRNAs were identified, and correlations between changed levels of specific lncRNAs and modulations in the abundance of mRNA transcripts of these genes (HNRNPC, FXR1, TP53, TARDBP, and MATR3) were found. Interestingly, the affected genes code for proteins involved in various regulatory processes, especially gene expression control through interactions with DNA or RNA regions. In conclusion, the results presented in this report suggest that changes in the levels of lncRNAs can considerably influence the pathomechanism of MPS through the dysregulation of the expression of certain genes, especially those involved in the control of the activities of other genes.

Cervical spine involvement in pediatric mucopolysaccharidosis patients: Clinical features, early diagnosis, and surgical management.

Mucopolysaccharidosis (MPS) is a progressive genetic disease that causes a deficiency in lysosomal enzymes, which play an important role in the degradation pathway of glycosaminoglycans. As a result of enzyme defects, mucopolysaccharides cannot be metabolized and thus accumulate. The cervical spine is one of the most commonly involved sites; thus, prompt surgical management before the onset of severe neurological deterioration is critical. However, because of the rarity of the disease, there is no standard treatment. In this review, we characterize the cervical spinal involvement in pediatric patients with MPS, describe the useful imaging technologies for diagnosis, and provide screening procedure for children with MPS. Surgical managements, including indications, surgical methods, possible difficulties, and solutions, are reviewed in detail.

Lečenje mukopolisaharidoze

Objectives. Mucopolysaccharidoses (MPS) are a collection of rare ailments of storage lysosomes distinguished by the aggregation of glycosaminoglycans (GAGs) at distinct regions of the eye. Follow-up is necessary to enable the right direction for the subsequent therapy. The objective of this research is to define the clinical presentation and treatment modalities in MPS patients. Methods. A total of 16 children diagnosed with MPS were followed-up for 10 years. All cases in this study underwent cycloplegic refraction using 1% cyclopentolate (API) and streak retinoscope (Keeler). Results. The findings confirmed that all patients (100%) presented with corneal cloudiness, half of them (50%) were diagnosed as having glaucoma and just above a third of children (37.5%) suffer from retinopathy. Conclusion. Early detection and diagnosis are crucial to protect the visual function, and experience at different levels is required for reaching the correct diagnosis.