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

BACKGROUND

One 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.

METHODS

The 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.

RESULTS

Included 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).

CONCLUSION

Although 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.

Capsular and retinaculum thickening in type II mucopolysaccharidosis: a novel MRI finding

Mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage diseases caused by a deficiency of glycosaminoglycan (GAG) catalytic enzymes, resulting in an accumulation of unprocessed or partly degraded GAGs in different tissues, including bones and joints. Notably, skeletal and joint abnormalities may be the first complaint that prompts patients to seek medical attention, especially in the milder forms of the disease. To our knowledge, there are no prior imaging reports that have documented capsuloligamentous thickening in patients with MPS on MRI. In this study, we present four cases of patients with clinically and genetically confirmed diagnosis of type II MPS, encompassing seven MRI examination of different joints, including cervical spine, hip, wrist, knee, and shoulder. All of the patients were male, aged between 14 and 35 years, and exhibited varying degrees of joint stiffness in the clinical examination and carpal tunnel syndrome in cases of the wrist joint was affected. None of the patients had a history of surgical procedures on the affected joint, other metabolic or deposit diseases, or sports activity practice. The MRI revealed significant capsuloligamentous and retinaculum thickening, up to eight times greater than the normal capsular thickness reported in the literature.

Experiences of Parents of Children with Mucopolysaccharidosis in Türkiye: A Qualitative Study

PURPOSE

Mucopolysaccharidosis increases morbidity and mortality by causing physical and mental limitations in children. Parents experience various difficulties, mostly due to delayed diagnosis and difficult treatment processes. This study aims to examine the experiences of parents regarding their child's illness process.

DESIGN AND METHODS

In this qualitative study, semi-structured in-depth interviews were conducted with parents (n = 10) who had a child who had suffered from MPS for at least six months. Interviews were conducted and recorded after the parents were contacted through the MPS-LH association and informed consent was obtained. The conducting and reporting of the research were carried out according to the "Consolidated criteria for reporting qualitative research (COREQ)" checklist.

RESULTS

The mean age of the parents was 41.3 ± 7.83. The diagnosis for most of the children was MPS type 4 A (n = 4) and the mean age of the children was 11.3 ± 6.0. Three main themes were identified: 1) psychosocial effects; 2) difficulties and needs; and 3) coping resources.

CONCLUSIONS

It was determined that the parents were affected socially and emotionally due to the child's diagnosis and the subsequent process.

IMPLICATIONS TO PRACTICE

It will be possible to provide the necessary support to parents with comprehensive nursing care that is planned according to the differing needs of children with MPS.

Psychobehavioral factors and family functioning in mucopolysaccharidosis: preliminary studies

Introduction

Mucopolysaccharidoses (MPS) constitute a group of progressive and multisystemic inherited metabolic diseases that profoundly affect both the mental health of patients and the wellbeing of their families. This study aims to evaluate the impact of MPS on family functioning and related factors.

Methods and results

Twenty-five patients with MPS, including types I (n = 4), II (n = 11), IIIB (n = 2), IVA (n = 3), and VI (n = 5), and their families participated in this study. The mean patient age was 13 years [standard deviation (SD): 7.7 years]. Behavioral and emotional problems were noted in 9.1% of all patients. While the type of MPS did not directly influence mental problems, the presence of neuronal involvement did (p = 0.006). Patients with MPS III exhibited difficulties primarily in emotional areas, conduct, hyperactivity, and peer problems. Importantly, both patients with MPS II and those with MPS III experienced a significant impact on communication [mean scores for communication domain: MPS II, 35.6 (SD: 24.3); MPS III, 35.0 (SD: 22.6)]; poorer communication was directly linked to worse adaptive behavior (p = 0.012), and worse adaptive behavior was associated with lower quality of life (p = 0.001). Quality of life and caregiver burden among family members did not significantly differ across MPS types; however, higher caregiver burden was negatively associated with quality of life (p = 0.002). Concerning family functioning, the most impacted domains included independence, intellectual/cultural orientation, activity/recreation, and expressiveness. Domain scores did not vary based on MPS type, treatment, or neurological involvement. Quality-of-life scores were positively associated with the cultural/intellectual domain score.

Conclusion

The impacts of quality of life and family extend beyond clinical characteristics and MPS type, strongly influenced by patient cognition and communication, as well as type of family functioning, especially those with greater cultural/intellectual skills of their family members. A multidisciplinary approach addressing the broader needs of individuals with MPS becomes essential. Techniques aimed at improving communication, including prompt interventions such as speech therapy and augmentative and alternative communication strategies, can contribute to overall family functioning improvement.

Evaluation of cardiac findings in mucopolysaccharidosis

PURPOSE

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.

METHOD

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).

RESULTS

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.

CONCLUSION

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.

15 Retinopathy in patients with mucopolysaccharidosis

The mucopolysaccharidoses are a group of inherited metabolic disorders resulting in abnormal degradation of glycosaminoglycans within lysosomes. Ophthalmic manifestations resulting in visual loss include corneal clouding, optic neuropathy and raised intraocular pressure, and retinopathy which occurs in MPS type I, II, III, IV. While corneal clouding may be stabilised with early treatment with HSCT or surgically treated with a corneal transplant, there is currently no known effective treatment for retinopathy.We conducted a prospective observational study of patients with MPS who underwent fundus examination, OPTOS imaging, OCT, and electroretinography.76 patients with MPS were studied, comprised of 45 MPSI, 9 MPSII, 13 MPSIV and 9 MPSVI patients. The age range was 3- 58 years of age. OPTOS imaging was performed in 65 individuals, OCT in 61, and electrodiagnostic assessments in 37 patients. Ten patients (7 MPSI, 3 MPS II) had fundoscopic signs of retinopathy, of which 5 had abnormal ERGs. Twenty one patients (17 MPSI, 2 MPSII, 2 MPSVI) had abnormalities on ERG, of which 5 had concurrent fundoscopic evidence of retinopathy. The onset of retinopathy in MPS patients was observed over a broad age range, with initial detection occurring between 2 and 53 years of age.Retinopathy can be diagnosed on examination, imaging, or ERG in MPS patients as young as 2 years of age. The development of novel medicines, such as gene therapy, have potential to stabilise or improve retinopathy in the future. Therefore, phenotypic and natural history information pertaining to retinopathy in MPS is extremely valuable.

Changes in Corneal Clouding Over Time in Patients With Mucopolysaccharidosis

PURPOSE

Mucopolysaccharidoses (MPSs) are a rare group of lysosomal storage disorders characterized by the accumulation of incompletely degraded glycosaminoglycans (GAGs) in multiple organ systems, including the eye. Visual loss occurs in MPS predominantly due to corneal clouding. Despite the success of enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) in improving many systemic manifestations of MPS, less is known about their effect on corneal clouding. This study prospectively analyses the effect of both ERT and HSCT on corneal clouding using objective measures over time.

METHODS

This is a prospective longitudinal observational study. Corneal clouding was assessed in each participant using slitlamp, digital slit-lamp photographs, and an iris camera (Corneal Opacification Measure [COM] and the Pentacam system).

RESULTS

Data were collected for 65 participants: 39 MPS I (Hurler), 5 MPS II (Hunter), 12 MPS IV (Morquio), and 9 MPS VI (Maroteaux-Lamy). Follow-up data are available for 45 participants (29 MPS I, 3 MPS II, 6 MPS IV, and 7 MPS VI).

CONCLUSIONS

This study found corneal clouding to be stable in most participants with MPS I, II, IV, and VI over a follow-up period of 5 to 75 months (median of 30 months) when measured with clinical corneal grading systems, graded digital slit-lamp images, and iris camera COMs. For those with Pentacam densitometry measures, there was a progression of corneal clouding, on average, in those with MPS I and MPS VI. There was no apparent difference in progression of corneal clouding between patients who were on ERT, HSCT, or no treatment.

Tissue doppler echocardiographic evaluation of cardiac functions in children with mucopolysaccharidosis type III disease

BACKGROUND

Mucopolysaccharidosis type III (MPS III) is an extremely rare group of diseases among all MPS types. In recent years, there are studies about the presence and importance of cardiac involvement in MPS III patients as in other types of MPS.

AIM

The aim of our study is to evaluate the cardiac functions of MPS III patients in pediatric age by using the M-mode, 2D, and Tissue Doppler echocardiographic measurements.

METHODS

The study was conducted prospectively between September and December 2020. Fifteen MPS III patients and 15 healthy volunteers were included in the study.

RESULTS

The mean Tei indexes of all three regions including left ventricle (LV), right ventricle (RV), and interventricular septum (IVS) were higher in MPS III patients compared to the control group (0.43/0.36 for LV and 0.44/0.37 for RV and 0.41/0.35), respectively. Diastolic function parameters of MPS III Patients were worse than the control group. In MPS III patients, eight (53.3%) patients had valvular dysfunction, three (20%) patients asymmetric septal hypertrophy and four (26.7%) patients LV concentric remodeling pattern. We detected an increase of z score above +2 in aortic valve annulus, sinuses of Valsalva, IVS diastole diameter and also in the LV posterior wall diastole diameter measurements in some MPS III patients.

CONCLUSION

We conclude that cardiac monitoring of MPS III patients is very important in terms of early detection and treatment of cardiac problems that may arise. Cardiac evaluation of larger series of MPS III patients are needed to make a better decision.

Long-Term Outcomes of Big Bubble Deep Anterior Lamellar Keratoplasty in Mucopolysaccharidoses: A Retrospective Case Series and Review of the Literature

PURPOSE

The purpose of this study was to report the long-term surgical and visual outcomes of patients with mucopolysaccharidoses (MPS) after big bubble deep anterior lamellar keratoplasty (BB-DALK).

METHODS

This was a retrospective case series of patients with MPS who underwent BB-DALK at a single academic institution. All patients had corneal clouding secondary to MPS limiting visual acuity for which keratoplasty was indicated. Each patient was evaluated and underwent surgery by a single surgeon. Reported data included age at keratoplasty, sex, MPS type, best spectacle-corrected visual acuity, change in pachymetry, ocular comorbidities, surgical complications, and MPS-related medication use.

RESULTS

Outcomes of 12 eyes from 7 patients with MPS type I (Hurler, Scheie, and Hurler-Scheie) are reported using the newest nomenclature. The mean follow-up was 5.58 years (range: 1-10 years). All cases underwent BB-DALK with a type 1 big bubble during the surgery. Two cases (16.6%) required rebubbling because of partial Descemet membrane detachment. One case was complicated by a suture abscess and required a penetrating keratoplasty. No episodes of rejection occurred. Statistically significant improvement in the best spectacle-corrected visual acuity (from a mean 0.85-0.33 logarithm of the minimum angle of resolution, P = logarithm of the minimum angle of resolution 0.0054) and pachymetry (mean reduction of -145.4 μm, P = 0.0018) was observed.

CONCLUSIONS

BB-DALK seems to be an acceptable long-term surgical option in patients with MPS. Our findings suggest that this technique is reproducible and can achieve clear corneal grafts with good visual results on a long-term follow-up.

Evaluation of bone health in patients with mucopolysaccharidosis

INTRODUCTION

This study aimed to evaluate the relationship between clinical findings, height and weight standard deviation scores, 25-hydroxyvitamin D₃ (25(OH)D₃) level, and dual-energy X-ray absorptiometry (DXA) results in patients diagnosed with mucopolysaccharidosis (MPS), where effective current treatments such as enzyme replacement therapy (ERT) can be accessed.

MATERIALS AND METHODS

25(OH)D₃ level was measured in 126 patients with MPS (17 with MPS I, 14 with MPS II, 18 with MPS III, 33 with MPS IVA, and 44 with MPS VI; 24-524 months). DXA was performed in 45 of these patients (8 with MPS I, 4 with MPS II, 4 with MPS III, 12 with MPS IVA, and 17 with MPS VI; 62-197 months; all patients were under 18 when DXA was performed) to assess bone mineral density (BMD) of the lumbar spine.

RESULTS

In total, 67.5% patients had a short stature, and 50% of them were underweight for their age. Of the patients, 13.5% were immobile, 28.6% had 25(OH)D₃ deficiency, and 30.2% had an insufficient level of 25(OH)D₃. BMD z score of 45 patients was - 2.5 ± 1.7. In 40% patients, it was <  - 2. However, after correction for height-for-age z score (HAZ), HAZ-adjusted BMD z score was - 0.1 ± 0.9. In 2.2% patients, it was <  - 2.

CONCLUSION

The low BMD z score prevalence reported with DXA was misleadingly higher in children with MPS and short stature. To prevent exposure to unnecessary antiresorptive treatments in these children, the effect of severe short stature and bone geometry on DXA measurements should be considered; further studies on bone health are warranted.

Damage of the cardiovascular system in lysosomal storage disease - mucopolysaccharidosis

The analysis of literature data reflecting the issues of the pathology of the cardiovascular system in mucopolysaccharidosis are presented. It was found out that heart and vessels damage is one of the cardinal signs of this pathology, often leading to death. Cardiac pathology is recorded in all types of mucopolysaccharidosis, but it is most significant for patients with three clinical variants of Hurler syndrome, Hunter, and Maroteaux-Lamy syndromes. Typical signs of damage to the cardiovascular system in mucopolysaccharidosis are thickening of the valves with the development of their dysfunction (while the severity of damage to the left-sided valves is more pronounced), myocardial hypertrophy, conduction disturbance, coronary artery disease, arterial hypertension. Many researchers emphasize the difficulties of clinical and functional examination of the cardiovascular system in patients with mucopolysaccharidosis, which is due to the presence of physical and intellectual limitations in patients, ands a gradual increase in symptoms. For the treatment of cardiovascular pathology at mucopolysaccharidosis, medical and surgical methods are used, including enzyme replacement therapy and stem cell transplantation.

Hip disease in Mucopolysaccharidoses and Mucolipidoses: A review of mechanisms, interventions and future perspectives

The hips are frequently involved in inheritable diseases which affect the bones. The clinical and radiological presentation of these diseases may be very similar to common hip disorders as developmental dysplasia of the hip, osteoarthritis and avascular necrosis, so the diagnosis may be easily overlooked and treatment may be suboptimal. Mucopolysaccharidosis (MPS) and Mucolipidosis (ML II and III) are lysosomal storage disorders with multisystemic involvement. Characteristic skeletal abnormalities, known as dysostosis multiplex, are common in MPS and ML and originate from intra-lysosomal storage of glycosaminoglycans in cells of the cartilage, bones and ligaments. The hip joint is severely affected in MPS and ML. Hip pathology results in limitations in mobility and pain from young age, and negatively affects quality of life. In order to better understand the underlying process that causes hip disease in MPS and ML, this review first describes the normal physiological (embryonic) hip joint development, including the interplay between the acetabulum and the femoral head. In the second part the factors contributing to altered hip morphology and function in MPS and ML are discussed, such as abnormal development of the pelvic- and femoral bones (which results in altered biomechanical forces) and inflammation. In the last part of this review therapeutic options and future perspectives are addressed.

Failures of Endochondral Ossification in the Mucopolysaccharidoses

PURPOSE OF REVIEW

The mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders characterized by abnormal accumulation of glycosaminoglycans (GAGs) in cells and tissues. MPS patients frequently exhibit failures of endochondral ossification during postnatal growth leading to skeletal deformity and short stature. In this review, we outline the current understanding of the cellular and molecular mechanisms underlying failures of endochondral ossification in MPS and discuss associated treatment challenges and opportunities.

RECENT FINDINGS

Studies in MPS patients and animal models have demonstrated that skeletal cells and tissues exhibit significantly elevated GAG storage from early in postnatal life and that this is associated with impaired cartilage-to-bone conversion in primary and secondary ossification centers, and growth plate dysfunction. Recent studies have begun to elucidate the underlying cellular and molecular mechanisms, including impaired chondrocyte proliferation and hypertrophy, diminished growth factor signaling, disrupted cell cycle progression, impaired autophagy, and increased cell stress and apoptosis. Current treatments such as hematopoietic stem cell transplantation and enzyme replacement therapy fail to normalize endochondral ossification in MPS. Emerging treatments including gene therapy and small molecule-based approaches hold significant promise in this regard. Failures of endochondral ossification contribute to skeletal deformity and short stature in MPS patients, increasing mortality and reducing quality of life. Early intervention is crucial for effective treatment, and there is a critical need for new approaches that normalize endochondral ossification by directly targeting affected cells and signaling pathways.

Hearing loss in patients with mucopolysaccharidoses-1 and -6 after hematopoietic cell transplantation: A longitudinal analysis

Hearing loss is frequently seen in mucopolysaccharidoses (MPS) patients. Although hematopoietic cell transplantation (HCT) increases overall survival, disease progression is observed in certain tissues. This study describes the course of hearing loss (HL) over time in transplanted MPS patients. Transplanted MPS patients between 2003 and 2018 were included and received yearly audiological evaluation, including auditory brainstem response (ABR) or pure tone audiometry (PTA). Twenty-eight MPS-1 and four MPS-6 patients were analyzed with a median follow-up of 5 years (range 11 months-16 years). Air conduction threshold improved significantly over time (P < .001) with a PTA 1-year post-HCT of 50 ± 0.7 dB to 23 ± 11 dB 13 years post-HCT. Bone conduction threshold worsened with a PTA 1 year post-HCT of 10 ± 7 dB to 18 ± 9 dB 13 years post-HCT (P = .34). The degree of HL varied from mainly mild-severe early after HCT to normal-mild at longer follow-up. The type of HL consisted of mainly conductive in the first years post-HCT in contrast to mainly sensorineural at longer follow-up. MRIs of the cerebellopontine angle did not show abnormalities. HL is still seen in patients with MPS despite HCT and consists of a conductive type early after HCT in contrast to a sensorineural type at longer follow-up in the majority of cases. Yearly follow-up of HL is necessary to timely intervene, as hearing is important in the speech and language development of children and their academic achievements.

Cardiac rhythm abnormalities - An underestimated cardiovascular risk in adult patients with Mucopolysaccharidoses

Patients with Mucopolysaccharidosis (MPS) have an increased risk of cardiovascular complications, conduction tissue abnormalities and arrhythmia; all rare but underestimated. It has been reported that conduction system defects are progressive in this group of patients and may result in sudden cardiac death. The aim of this study is to review our current practice and suggest best practice guidelines regarding the frequency of cardiac rhythm monitoring in this patient group. Seventy-seven adult MPS patients who attended metabolic clinics between 2013 and 2019 were included in this retrospective observational study. Patients were affected with different MPS types: MPS I (n = 33), MPS II (n = 16), MPS IV (n = 19), VI (n = 8) and VII (n = 1). The assessments included: 12‑lead electrocardiogram (ECG), 24-h ECG (Holter monitor), loop recorder/pacemaker interrogation assessment. Data from 12‑lead ECG (available from 69 patients) showed a variety of abnormalities: T wave inversion in a single lead III (n = 19), left ventricular hypertrophy (n = 14), early repolarization (n = 14), right axis deviation (RAD, n = 11), partial RBBB (n = 9), right bundle branch block (RBBB) (n = 1) and first degree AV block (n = 1). ECG changes of bundle branch block, RAD (left posterior fascicular block) could represent conduction tissue abnormality and equally could be related to the underlying lung tissue abnormality which is present in most of the patients with MPS. T wave abnormality in a single lead is usually insignificant in healthy individuals; however in MPS patients it could be as a result of chest shape. Among the 34 patients for who 24-hour ECG was available, sinus tachycardia was the most common rhythm noted (n = 9), followed by sinus bradycardia (n = 4), atrial fibrillation (AF) (n = 1) and atrio-ventricular nodal re-entry tachycardia (AVNRT) (n = 1). Permanent pacemaker was inserted in two patients. AF was observed in one patient with MPS II. In conclusion, we postulate that regular cardiac monitoring is required to warrant early detection of underlying conduction tissue abnormalities. In addition, 12‑lead ECG is the first line investigation that, if abnormal, should be followed up by 24-hour Holter monitoring. These findings warrant further research studies.

Left ventricular assessment in patients with mucopolysaccharidosis using conventional echocardiography and myocardial deformation by two-dimensional speckle-tracking method

OBJECTIVE

Mucopolysaccharidosis is a rare genetic disease characterized by the intralysosomal deposition of glycosaminoglycans. Cardiovascular impairment is a common feature. Cardiac signs and symptoms are underestimated due to the disease involvement in other organs. Enzyme replacement therapy can be used in mucopolysaccharidosis I, II, IV, and VI. Thus, the knowledge about the use of new echocardiography tools is relevant to improve the care of this population. This study aimed to describe left ventricular function assessment by conventional echocardiography and left ventricular global longitudinal strain analysis and compare the alterations in patients receiving enzyme replacement therapy and who had different ages at the start of therapy.

METHOD

Outpatient-based descriptive study. The patients were submitted to conventional echocardiography and left ventricular global longitudinal strain measurement.

RESULTS

Sixteen patients were evaluated; median age of 14.2 years (SD=5.2 years). Left ventricular hypertrophy was found in nine patients (56.2%). All patients had preserved left ventricular systolic function (Simpson and Teichholz). Nine (56.2%) patients showed alterations in left ventricular global longitudinal strain. The study showed a positive association between left ventricular hypertrophy and alteration in the left ventricular global longitudinal strain, and late start of enzyme replacement therapy and alteration in the left ventricular global longitudinal strain.

CONCLUSION

Echocardiographic alterations in patients with mucopolysaccharidosis were frequently observed, especially alterations in the left ventricular geometry and subclinical dysfunction. Patients who had a late enzyme replacement therapy start showed an association with worse left ventricular global longitudinal strain values, reinforcing the need for early diagnosis and treatment. The use of new echocardiographic tools may improve the follow-up of these patients.

General Anesthesia Management for Adult Mucopolysaccharidosis Patients Undergoing Major Spine Surgery

OBJECTIVE

Mucopolysaccharidosis (MPS) are a group of rare systemic lysosomal storage diseases associated with severe airway obstruction and cardiac disease, making anesthesia management difficult. Contemporary treatment extends the lifespan of affected individuals, increasing the need for major surgery in adulthood.

CLINICAL PRESENTATION AND INTERVENTION

We provided general anesthesia for 6 adult MPS patients undergoing spine surgery. The airway was assessed as difficult in all, with 2 receiving awake fiberoptic intubation and 1 successfully undergoing video-laryngoscopy, while 3 video-laryngoscopy procedures failed and required conversion to fiberoptic intubation. One patient developed ventricular fibrillation.

CONCLUSION

Adult MPS patients have substantial anesthesia risk.

Audiometric evaluation in individuals with mucopolysaccharidosis

OBJECTIVES

To characterize the audiometric evaluation and acoustic immittance measures in different types of mucopolysaccharidosis.

METHOD

Fifty-three mucopolysaccharidosis patients were evaluated. The classification consisted of type I (Hurler syndrome, Hurler-Scheie and Scheie syndrome), type II (Hunter syndrome), type III (Sanfilippo syndrome), type IV (Morquio syndrome), and type VI (Maroteaux-Lamy syndrome). Immittance audiometry and play or conventional threshold tone audiometry were used to obtain auditory thresholds and were chosen according to the patient's chronological age and ability to understand/respond to the procedure. The findings were analyzed using descriptive statistics and considering the recommendations for research involving human beings contained in Resolution CNE N° 466/2012.

RESULTS

Fifty-one subjects (96.2%) had hearing loss, and the conductive type was the most frequent. Only two (3.8%) patients presented bilateral thresholds within normal limits, one with type IV mucopolysaccharidosis and the other with type VI. There were 11 individuals (20.8%) with mucopolysaccharidosis type I with mixed hearing loss, 9 (16.9%) individuals with type I with conductive hearing loss and 9 (16.9%) with type VI with conductive hearing loss. Mild hearing loss was most common (37.3%), followed by moderately severe hearing loss (36.3%). The type B tympanometric curve (80.4%) was the most frequent.

CONCLUSIONS

Most of the individuals with mucopolysaccharidosis types I, II, III, IV and VI presented mixed or conductive hearing losses of mild to moderately severe degree, type B tympanograms and an absence of contralateral acoustic reflexes.

Anatomical changes and pathophysiology of the brain in mucopolysaccharidosis disorders

Mucopolysaccharidosis (MPS) disorders are caused by deficiencies in lysosomal enzymes, leading to impaired glycosaminoglycan (GAG) degradation. The resulting GAG accumulation in cells and connective tissues ultimately results in widespread tissue and organ dysfunction. The seven MPS types currently described are heterogeneous and progressive disorders, with somatic and neurological manifestations depending on the type of accumulating GAG. Heparan sulfate (HS) is one of the GAGs stored in patients with MPS I, II, and VII and the main GAG stored in patients with MPS III. These disorders are associated with significant central nervous system (CNS) abnormalities that can manifest as impaired cognition, hyperactive and/or aggressive behavior, epilepsy, hydrocephalus, and sleeping problems. This review discusses the anatomical and pathophysiological CNS changes accompanying HS accumulation as well as the mechanisms believed to cause CNS abnormalities in MPS patients. The content of this review is based on presentations and discussions on these topics during a meeting on the brain in MPS attended by an international group of MPS experts.

ENT and mucopolysaccharidoses

The mucopolysaccharidoses (MPS) are a heterogeneous group of inherited metabolic disorders, each associated with a deficiency in one of the enzymes involved in glycosaminoglycan (GAG) catabolism. Over time, GAGs accumulate in cells and tissues causing progressive damage, a variety of multi-organ clinical manifestations, and premature death. Ear, nose, and throat (ENT) disorders affect more than 90% of MPS patients and appear in the early stage of MPS; also reported are recurrent otitis media and persistent otitis media with effusion, macroglossia, adenotonsillar hypertrophy, nasal obstruction, obstructive sleep apnoea syndrome (OSAS), hearing loss, and progressive respiratory disorders. Undiagnosed MPS patients are frequently referred to otolaryngologists before the diagnosis of MPS is confirmed. Otolaryngologists thus have an early opportunity to recognize MPS and they can play an increasingly integral role in the multidisciplinary approach to the diagnosis and management of many children with MPS. The ENT commitment is therefore to suspect MPS when non-specific ENT pathologies are associated with repeated surgical treatments, unexplainable worsening of diseases despite correct treatment, and with signs, symptoms, and pathological conditions such as hepatomegaly, inguinal hernia, macrocephaly, macroglossia, coarse facial features, hydrocephalous, joint stiffness, bone deformities, valvular cardiomyopathy, carpal tunnel syndrome, and posture and visual disorders.

Craniosynostosis affects the majority of mucopolysaccharidosis patients and can contribute to increased intracranial pressure

BACKGROUND

The mucopolysaccharidoses are multisystem lysosomal storage diseases characterized by extensive skeletal deformities, including skull abnormalities. The objective of this study was to determine the incidence of craniosynostosis in the different mucopolysaccharidosis (MPS) types and its clinical consequences.

METHODS

In a prospective cohort study spanning 10 years, skull imaging and clinical evaluations were performed in 47 MPS patients (type I, II, VI, and VII). A total of 215 radiographs of the skull were analyzed. The presence and type of craniosynostosis, the sutures involved, progression over time, skull shape, head circumference, fundoscopy, and ventriculoperitoneal shunt (VPS) placement data were evaluated.

RESULTS

Craniosynostosis of at least one suture was present in 77% of all 47 MPS patients (≤ 6 years of age in 40% of all patients). In 32% of all MPS patients, premature closure of all sutures was seen (≤ 6 years of age in 13% of all patients). All patients with early closure had a more severe MPS phenotype, both in the neuronopathic (MPS I, II) and non-neuronopathic (MPS VI) patient groups. Because of symptomatic increased intracranial pressure (ICP), a VPS was placed in six patients, with craniosynostosis as a likely or certain causative factor for the increased pressure in four patients. One patient underwent cranial vault expansion because of severe craniosynostosis.

CONCLUSIONS

Craniosynostosis occurs in the majority of MPS patients. Since the clinical consequences can be severe and surgical intervention is possible, skull growth and signs and symptoms of increased ICP should be monitored in both neuronopathic and non-neuronopathic patients with MPS.

Spine challenges in mucopolysaccharidosis

PURPOSE

Mucopolysaccharidosis (MPS) are rare inherited metabolic diseases, causing lysosomal storage of mucopolysaccharides; clinical presentation involves skeletal system and particularly the spine. Anomalies include developing kyphosis at thoracolumbar junction, that can causes nervous symptoms, and dens hypoplasia with associated atlantoaxial subluxation that can cause myelopathy. We present our experience in the treatment of spine pathology in MPS.

METHODS

Medical treatments of MPS seem to have little impact on spine disease: treatment of cervical instability often includes surgical decompression and stabilization, as in patient MPS1 that we present, while thoracic lumbar kyphosis is treated by bracing and, in severe cases, with surgery. Bracing is more effective in kyphosis under 40° Cobb. Our surgical cases with thoracic lumbar kyphosis over 40° Cobb, treatment include the first one ever described by only posterior approach with vertebrectomy in MPS and a case of lateral costo-transverse approach instrumented correction.

RESULTS

Surgical patients had no major complications after surgery and CT scan at follow-up showed complete fusion without loss of correction, even if in a cervical case we used an adult rigid instrumentation in a four year-and-six month-old girl (11 years follow-up) and in thoracic lumbar kyphosis case treated by vertebrectomy due to diminutive anatomy we positioned interbody cage in suboptimal position.

CONCLUSIONS

Bracing is a viable treatment strategy in thoracic lumbar kyphosis and can obtain good clinical results at medium terms follow-up even if kyphosis deformity remains in radiographs. Surgical treatment is effective in severe evolving cases both at cervical and thoracic lumbar level, main difficulties arose from unavailability of dedicated instrumentation in very young patient, as even smallest devices available are often too big.

Cardiac features and effects of enzyme replacement therapy in Taiwanese patients with Mucopolysaccharidosis IVA

BACKGROUND

Cardiac abnormalities have been observed in patients with mucopolysaccharidosis (MPS) of any type, with the most documented abnormalities being valvular heart disease and cardiac hypertrophy. However, few studies have focused on the cardiac features of MPS IVA.

METHODS

We reviewed the medical records, echocardiograms, and electrocardiograms of 32 Taiwanese patients with MPS IVA (16 males and 16 females; median age, 10.8 years; age range, 1.1 to 29.1 years) as well as the echocardiographic data of six patients who received enzyme replacement therapy (ERT) for 3-6 years.

RESULTS

Echocardiographic examinations (n = 32) revealed mean z scores of left ventricular mass index (LVMI), interventricular septum diameter in diastole (IVSd), left ventricular posterior wall diameter in diastole (LVPWd), and aortic diameter of 0.94, 2.70, 0.39, and 3.26, respectively. Z scores > 2 were identified in 25%, 50%, 29%, and 69% of the LVMI, IVSd, LVPWd, and aortic diameter values, respectively. Diastolic dysfunction [reversed ratio between early and late (atrial) ventricular filling velocity (E/A ratio < 1)] was identified in four patients (13%), however, the ejection fraction was normal (50-75%) in all of the patients. Sixteen patients (50%) had valvular heart disease and most were of mild degree. Fourteen (44%) had valvular stenosis, and 10 (31%) had regurgitation. The z scores of LVMI, IVSd, LVPWd, and aortic diameter, the severity scores of aortic stenosis and regurgitation, and the existence of a thickened interventricular septum were all positively correlated with increasing age (p < 0.05). For the 14 patients with valve thickening, the z scores of LVMI, IVSd and aortic diameter were all larger than those of the 18 patients without valve thickening (p < 0.05). For two patients who started ERT at a younger age (1.4 and 2.8 years, respectively), the z scores for LVMI, IVSd, and LVPWd all decreased after ERT.

CONCLUSIONS

A large proportion of the patients with MPS IVA had valvular heart disease and cardiac hypertrophy. Cardiac abnormalities worsened with increasing age in accordance with the progressive nature of this disease. ERT appeared to be effective in stabilizing or reducing cardiac hypertrophy, and better results may have been associated with starting ERT at a younger age.

Mitral Regurgitation and Heart Failure as the First Presentation in a Patient with Features of Two Connective Tissue Disorders: A Rare Combination of Mucopolysaccharidosis and Osteogenesis Imperfecta?

Connective tissue disorders sometimes involve cardiovascular systems. This report describes the case of a middle-aged man with mitral regurgitation and heart failure. He had distinctive features of mucopolysaccharidosis type (MPS) III, but no gene mutations that were known to be associated with MPS. Meanwhile, he had a COL1A2 gene mutation that is associated with osteogenesis imperfecta (OI), and had some features that were compatible with OI. The patient might have had a rare connective tissue disorder with the characteristics of MPS III and OI, which was initially detected as a result of the cardiovascular manifestations.

Stand-alone craniocervical decompression is feasible in children with mucopolysaccharidosis type I, IVA, and VI

BACKGROUND CONTEXT

In patients with mucopolysaccharidosis (MPS), glycosaminoglycan deposits in the dura mater and supporting ligaments cause spinal cord compression and consecutive myelopathy, predominantly at the craniocervical junction. Disease characteristics of craniocervical stenosis (CCS) in patients with MPS differ profoundly from other hereditary and degenerative forms. Because of high periprocedural morbidity and mortality, patients with MPS pose a substantial challenge to the inexperienced medical care provider. As literature remains scarce, we present our experience with a large cohort of patients with MPS treated for CCS without atlanto-occipital instrumentation.

PURPOSE

The present study aimed to describe a safe and least traumatic approach for treating CCS in children with MPS, avoiding primary instrumentation.

STUDY DESIGN

This is a prospective follow-up (cohort) study.

PATIENT SAMPLES

We report 15 consecutive patients with CCS related to MPS, who were treated with stand-alone cervical decompression.

OUTCOME MEASURES

Myelopathy was assessed using magnetic resonance imaging (MRI), somatosensory evoked potentials, and clinical evaluation. Cervical instability was evaluated using plain x-ray and MRI. The disability status is quantified using either the Karnofsky or Lansky Performance Score.

METHODS

We describe 15 consecutive patients treated with craniocervical decompression. Data were collected prospectively. The mean follow-up is 6 years (5 standard deviation). The technique and treatment principles are described.

RESULTS

The overall clinical outcome in this patient cohort is good (mean Karnofsky Performance Score of 80). No patient developed signs of C0-C1-C2 instability or progressive myelopathy. Restenosis occurred in seven patients, requiring a total of eight reoperations.

CONCLUSIONS

Surgery in patients with MPS is associated with high morbidity and mortality of up to 4.2%. Because of the unique nature of the disease, recurring stenosis is inevitable. To shorten the procedure time and simplify the anticipated reoperation, we provide data that craniocervical decompression is feasible without the necessity of primary osteosynthesis. In the absence of craniocervical instability, decompression surgery without occipitocervical stabilization yields good postoperative results and challenges the long-standing paradigm of prophylactic craniocervical fixation.

Growth impairment in mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders that affect regulation of glycosaminoglycan (GAG) processing. In MPS, the lysosomes cannot efficiently break down GAGs, and the specific GAGs accumulated depend on the type of MPS. The level of impairment of breakdown varies between patients, making this one of the many factors that lead to a range of clinical presentations even in the same type of MPS. These clinical presentations usually involve skeletal dysplasia, in which the most common feature is bone growth impairment and successive short stature. Growth impairment occurs due to the deposition and retention of GAGs in bone and cartilage. The accumulation of GAGs in these tissues leads to progressive damage in cartilage that in turn reduces bone growth by destruction of the growth plate, incomplete ossification, and imbalance of growth. Imbalance of growth leads to various skeletal abnormalities including disproportionate dwarfism with short neck and trunk, prominent forehead, rigidity of joints, tracheal obstruction, kyphoscoliosis, pectus carinatum, platyspondyly, round-shaped vertebral bodies or beaking sign, underdeveloped acetabula, wide flared iliac, coxa valgus, flattered capital femoral epiphyses, and genu valgum. If left untreated, skeletal abnormalities including growth impairment result in a significant impact on these patients' quality of life and activity of daily living, leading to high morbidity and severe handicap. This review focuses on growth impairment in untreated patients with MPS. We comprehensively describe the growth abnormalities through height, weight, growth velocity, and BMI in each type of MPS and compare the status of growth with healthy age-matched controls. The timing, the degree, and the difference in growth impairment of each MPS are highlighted to understand the natural course of growth and to evaluate future therapeutic efficacy.

Pathophysiology, evaluation, and management of sleep disorders in the mucopolysaccharidoses

The mucopolysaccharidoses (MPS) represent a heterogeneous group of lysosomal storage disorders, each one associated with a deficiency in one of the enzymes involved in glycosaminoglycan degradation. Sleep disorders are a frequent manifestation of all types of MPS. Underlying causes are diverse and comprised of both respiratory and central nervous system (CNS) abnormalities. Sleep disordered breathing such as obstructive sleep apnea and nocturnal hypoventilation can arise in patients with upper airway obstruction and/or with alterations in respiratory mechanics, causing restrictive pulmonary disease. MPS patients with CNS disease can also develop sleep disturbances unrelated to ventilatory impairments, often associated with severe behavioral problems or night-time epileptic seizures. The present review discusses the pathophysiology, evaluation, and management of sleep disorders in MPS based on information from a meeting on the brain in MPS, attended by an international group of experts (April 28-30, 2016, Stockholm, Sweden), and additional literature searches.

Surgical management of neurological manifestations of mucopolysaccharidosis disorders

The mucopolysaccharidosis (MPS) disorders are ultra-rare lysosomal storage disorders associated with progressive accumulation of glycosaminoglycans (GAGs) in cells and tissues throughout the body. Clinical manifestations and progression rates vary widely across and within the different types of MPS. Neurological symptoms occur frequently, and may result directly from brain damage caused by infiltration of GAGs, or develop secondary to somatic manifestations such as spinal cord compression, hydrocephalus, and peripheral nerve entrapment. Management of secondary neurological manifestations often requires surgical correction of the underlying somatic cause. The present review discusses the surgical management of neurological disease in patients with MPS, including diagnostic imaging. Background information is derived from presentations and discussions during a meeting on the brain in MPS, attended by an international group of experts (April 28-30, 2016, Stockholm, Sweden), and additional literature searches.

Practical management of behavioral problems in mucopolysaccharidoses disorders

The mucopolysaccharidosis (MPS) disorders are caused by deficiencies of specific lysosomal enzymes, resulting in progressive glycosaminoglycan (GAG) accumulation in cells and tissues throughout the body. Excessive GAG storage can lead to a variety of somatic manifestations as well as primary and secondary neurological symptoms. Behavioral problems (like hyperactivity, attention difficulties, and severe frustration) and sleeping problems are typical primary neurological symptoms of MPS caused by GAG accumulation in neurons, and are frequently observed in patients with MPS I, II, III, and VII. As these problems often place a significant burden on the family, proper management is important. This review summarizes current insights into behavioral and sleeping problems in MPS disorders and the most optimal management approaches, as presented and discussed during a meeting of an international group of experts with extensive experience in managing and treating MPS.

Epilepsy in mucopolysaccharidosis disorders

The mucopolysaccharidosis (MPS) disorders are caused by deficiencies of specific lysosomal enzymes involved in the catabolism of glycosaminoglycans (GAGs). The resulting GAG accumulation in cells and tissues throughout the body leads to progressive multi-organ dysfunction. MPS patients present with several somatic manifestations, including short stature, musculoskeletal abnormalities, and cardiorespiratory dysfunction, and several primary and secondary neurological signs and symptoms. Epileptic seizures are neurological signs of MPS thought to develop due to accumulation of GAGs in the brain, triggering alterations in neuronal connectivity and signaling, and release of inflammatory mediators. The amount of literature on the prevalence, pathophysiology, clinical features, and management of epileptic seizures in patients with MPS is limited. This review discusses current knowledge on this topic, as well as two case examples, presented and discussed during a closed meeting on MPS and the brain among an international group of experts with extensive experience in managing and treating MPS.

Hydrocephalus and mucopolysaccharidoses: what do we know and what do we not know?

INTRODUCTION

The precise incidence of hydrocephalus in patients with mucopolysaccharidoses (MPS) is hard to determine, because the condition lacks a formal, consensus-based definition. The diagnosis of hydrocephalus depends on symptom profile, presence of neuroimaging features, and the outcome of diagnostic tests. Although numerous techniques are used to identify MPS patients who are most likely to have hydrocephalus and respond to treatment, no definitive method exists to prove diagnosis.

PURPOSE

The authors propose an algorithm to aid in the diagnosis and management of hydrocephalus in MPS patients.

CONCLUSIONS

The theory of venous hypertension associated with the morphological changes in the skull base and craniocervical junction indicate the need for future neuroimaging studies including cerebrospinal fluid (CSF) and venous flow measurements to monitor hydrocephalus progression and select therapeutic interventions in MPS patients. Preoperative planning should also be based on the increased risk of intraoperative and postoperative hemorrhagic complications.

Influence of Corneal Opacity on Intraocular Pressure Assessment in Patients with Lysosomal Storage Diseases

AIMS

To investigate an influence of mucopolysaccharidosis (MPS)- and Morbus Fabry-associated corneal opacities on intraocular pressure (IOP) measurements and to evaluate the concordance of the different tonometry methods.

METHODS

25 MPS patients with or without corneal clouding, 25 Fabry patients with cornea verticillata ≥ grade 2 and 25 healthy age matched controls were prospectively included into this study. Outcome measures: Goldmann applanation tonometry (GAT); palpatory assessment of IOP; Goldmann-correlated intraocular pressure (IOPg), corneal-compensated intraocular pressure (IOPcc), corneal resistance factor (CRF) and corneal hysteresis (CH) assessed by Ocular Response Analyzer (ORA); central corneal thickness (CCT) and density assessed with Pentacam. Statistical analysis was performed using linear mixed effect models and Spearman correlation coefficients. The concordance between tonometry methods was assessed using Bland-Altman analysis.

RESULTS

There was no relevant difference between study groups regarding median GAT, IOPg, IOPcc and CCT measurements. The limits of agreement between GAT and IOPcc/IOPg/palpatory IOP in MPS were: [-11.7 to 12.1mmHg], [-8.6 to 15.5 mmHg] and [- 5.4 to 10.1 mmHg] respectively. Limits of agreement were less wide in healthy subjects and Fabry patients. Palpatory IOP was higher in MPS than in healthy controls and Fabry patients. Corneal opacity correlated more strongly with GAT, IOPg, CH, CRF, CCT and corneal density in MPS (r = 0.4, 0.5, 0.5, 0.7, 0.6, 0.6 respectively) than in Fabry patients (r = 0.3, 0.2, -0.03, 0.1, 0.3, -0.2 respectively). In contrast, IOPcc revealed less correlation with corneal opacity than GAT in MPS (r = 0.2 vs. 0.4).

CONCLUSIONS

ORA and GAT render less comparable IOP-values in patients suffering from MPS-associated corneal opacity in comparison to Fabry and healthy controls. The IOP seems to be overestimated in opaque MPS-affected corneas. GAT, IOPg and biomechanical parameters of the cornea correlate more strongly with the corneal clouding than IOPcc in MPS patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01695161.

Airway changes in children with mucopolysaccharidoses: CT evaluation

Objective: To assess the CT findings of the airway in children with mucopolysaccharidoses (MPS).

Material and Methods: The study included 13 patients (9 boys, 4 girls; age range 2-17 years; mean age 9.2 years) with MPS: 6 with Hunter syndrome, 3 with Maroteaux-Lamy syndrome, 2 with Sanfilippo syndrome, 1 with Hurler/Scheie syndrome and 1 with Morquio syndrome. CT of the airways was done in the axial section with 3-mm collimation from the oropharynx at the level of C3 to the base of the lung. The shape of the vocal cords and trachea at the level of T1 was evaluated. The tracheal surface area (TSA) at the level of T1 was measured both in patients and in age-matched subjects.

Results: CT showed an abnormality of the vocal cords in 7 of the 13 patients. Six patients had an abnormal shape and 7 had an inhomogenous density. The abnormalities included elliptical (5 of 6) and star-shaped (1 of 6) cords. Eight of 13 tracheas were also abnormal, either U-shaped (6 of 8) or worm-shaped (2 of 8). The TSA was significantly smaller in patients (79.6±28.9 mm2) than in control subjects (138.1±50.1 mm2). The TSA of those ≤⃒9 years was 61.4±15.2 mm2 as compared with 99.9±23.5 mm2 for the control group. The TSA of patients ≥11 years was 107.1±25.3 mm2 as compared with 187.6±32.0 mm2 for the control group.

Conclusion: Significant changes in the shape of the vocal cords and trachea in patients with MPS were found. The most common abnormal configuration of trachea was the U-shape. The TSA was smaller in patients with MPS than in controls. The airway changes may be due to abnormal submucosal storage of substances such as keratan or dermatan sulfate.

Elevated TNF-α is associated with pain and physical disability in mucopolysaccharidosis types I, II, and VI

BACKGROUND

Children and adults with the lysosomal storage diseases mucopolysaccharidosis (MPS) types I, II and VI live shortened lives permeated by chronic pain and physical disability. Current treatments do not alleviate these problems. Thus there is a critical need to understand the mechanism of chronic pain and disability in MPS in order to improve the way we treat patients. A potential target is inflammation.

HYPOTHESIS

We hypothesized that excessive inflammation mediated by the tumor necrosis factor-α (TNF-α) inflammatory pathway is the fundamental cause of much of the chronic pain and physical disability in MPS.

METHODS

55 patients with MPS I, II, or VI were enrolled over the course of a 5-year prospective longitudinal natural history study and evaluated annually for 2-5years. 51 healthy controls were enrolled in a separate cross-sectional study of bone and energy metabolism. TNF-α was measured by ELISA. Pain and physical disability were measured by the Children's Health Questionnaire - Parent Form 50 (CHQ-PF50). Differences in log-transformed TNF-α levels and associations with CHQ domains were evaluated using a linear mixed effects model with random intercept.

RESULTS

TNF-α levels were measured in 48 MPS (age: 5-17years; 35% female) and 51 controls (age: 8-17years; 53% female). Among MPS, 22 (46%) were treated with hematopoietic cell transplantation (HCT) alone, 24 (50%) with enzyme replacement therapy (ERT) alone, and 2 (4%) with both HCT and ERT. TNF-α levels are higher in MPS compared to healthy controls (p<0.001). Higher TNF-α levels are associated with increased pain and decreased physical function, social limitations due to physical health, and physical summary score (all p<0.05). TNF-α levels were not significantly associated with the general health score. TNF-α levels did not change significantly over time in MPS.

CONCLUSIONS

Higher TNF-α levels are implicated in the pain and decreased physical function present in individuals with MPS despite treatment with ERT and/or HCT, suggesting that TNF-a inhibition could potentially be a useful adjunctive therapy. Further investigation into the role of TNF-α inhibition in MPS to decrease pain and improve physical function is indicated.

Cardiac structure and function and effects of enzyme replacement therapy in patients with mucopolysaccharidoses I, II, IVA and VI

BACKGROUND

While enzyme replacement therapy (ERT) has been shown to improve endurance and joint mobility for patients with mucopolysaccharidoses (MPS) I, II, IVA and VI, the impact of ERT on cardiac abnormalities remains uncertain.

METHODS

Medical records and echocardiograms of 28 Taiwanese MPS patients (9 with MPS I, 7 with MPS II, 7 with MPS IVA, and 5 with MPS VI) treated with ERT for 1-10.8years were retrospectively reviewed.

RESULTS

At start of ERT, z scores>2 were identified in 46% and 75% for left ventricular mass index (LVMI) and interventricular septum thickness in diastole (IVSd) in these patients, respectively. Twenty-four patients (86%) had valvular heart disease. After ERT, the mean IVSd z score of all patients decreased significantly from 3.87 to 2.57 (p=0.016). For 11 patients starting ERT before 12years of age, z scores for both LVMI and IVSd decreased significantly (p<0.01) after ERT. However, the condition of valve regurgitation or stenosis did not show improvement despite ERT.

CONCLUSIONS

ERT was shown to be an effective therapy for reducing cardiac hypertrophy, with best results seen when ERT was started at an early age. ERT, however, had little impact on valvular heart disease.

Therapies for the bone in mucopolysaccharidoses

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.

Improvements in sensorineural hearing loss after cord blood transplant in patients with mucopolysaccharidosis

OBJECTIVE

To objectively determine changes in sensorineural hearing in children with mucopolysaccharidosis (MPS) by comparing audiological data before and after hematopoietic stem cell transplantation (HSCT).

DESIGN

Retrospective medical chart analysis.

SETTING

Tertiary referral hospital.

PATIENTS

Thirty pediatric patients with the diagnosis of MPS who underwent HSCT and had audiological data before and after HSCT. Data were extracted from medical charts for patients seen at our institution from January 1, 1999, to December 1, 2009.

MAIN OUTCOMES MEASURES

Hearing was assessed using behavioral audiometry testing and auditory brainstem responses (ABR) before and after HSCT. Patient demographics, diagnosis, and age at HSCT were also evaluated.

RESULTS

Thirty patients with MPS were included. Four (13%) had MPS type 3a, 2 (7%) had MPS type 2, and 24 (80%) had MPS type 1. The average age at HSCT was 19 months (range, 5-44 months). Hearing improvement was evaluated by audiogram (20 patients), ABR (8 patients), and qualitative measures (30 patients). On average, patients did not show improvement on audiogram (P = .28; paired t test). The ABR click threshold improved 19 dB on average (P < .001). Qualitatively, 3 patients had normal hearing before and after HSCT. Of the remaining 27 patients, 20 (67%) showed improvement in sensorineural hearing (P < .001). Five (17%) had hearing loss and did not improve. Two (7%) had worsening hearing. Hematopoietic stem cell transplantation at the age of 25 months or younger was significantly correlated with hearing improvement (P = .03).

CONCLUSIONS

Hematopoietic stem cell transplantation may provide improvement in MPS-associated sensorineural hearing loss. Hearing improvement is more likely to occur in patients who undergo transplantation at 25 months or younger.

Assessment of hearing loss by pure-tone audiometry in patients with mucopolysaccharidoses

BACKGROUND

Patients with mucopolysaccharidoses (MPS) often have hearing loss. However, the characterization of hearing loss by pure-tone audiometry (PTA) in this rare disease population and its relationship to age and treatment is limited.

METHODS

PTA was performed in 39 patients with MPS (29 males and 10 females; 3 with MPS I, 21 with MPS II, 9 with MPS IVA, and 6 with MPS VI; median age, 11.9 years; age range, 4.4-34.2 years). The degree of hearing loss was classified by the age-independent World Health Organization (WHO) clinical guidelines.

RESULTS

Hearing loss by PTA was present in 85% (33/39) of patients and was categorized as mild (26-40 dB) in 18%, moderate (41-60 dB) in 36%, severe (61-80 dB) in 23%, and profound (≥81dB) in 5%. Among the patients with hearing loss, 33% were classified as mixed type (conductive and sensorineural), 30% as pure conductive type, 27% as pure sensorineural type, and 9% were undefined. The means of the right and left ear hearing thresholds at 2000 and 4000 Hz by air conduction (AC) and at 500, 1000, 2000, and 4000 Hz by bone conduction (BC) were all positively correlated with age (p<0.05). In the 6 patients with MPS II or VI who underwent follow-up PTA after ventilation tube insertion and enzyme replacement therapy for 1.9 to 8.5 years, all showed improvements in AC and BC of the better ear, as well as in the air-bone gap.

CONCLUSIONS

Hearing impairment is common in MPS. Early otolaryngological evaluation and intervention are recommended. These findings and the follow-up data can be used to develop quality of care strategies for patients with MPS.

Cardiovascular abnormalities in Taiwanese patients with mucopolysaccharidosis

BACKGROUND

The mucopolysaccharidoses (MPS) are a group of rare inherited metabolic diseases that can cause damages in various organs including the heart. This study aimed to review the medical records of Taiwanese patients with MPS in order to evaluate the cardiovascular involvement in those patients.

METHODS

From 2000 to 2012, the medical records of 60 patients with MPS in a tertiary medical center in Taiwan were retrospectively reviewed. Data on cardiac measurements and functions were obtained from previously performed echocardiograms and electrocardiograms. Cardiac parameters were analyzed according to MPS types and patients' age.

RESULTS

The most frequent MPS type was type II (43%). Overall, heart conditions such as thick interventricular septum (55%), asymmetric septal hypertrophy (42%) and mitral valve prolapse (33%) were common, while cardiac enlargement was infrequently seen. Valvular stenosis/regurgitation and cardiac hypertrophy were more common in patients with MPS I, II, and VI when compared with other MPS types. Cardiovascular abnormalities including valvular deformation and thickening, thick interventricular septum and diastolic dysfunction were found to progress with age.

CONCLUSIONS

The anatomical changes of cardiovascular systems were common in all types of MPS patients, especially in MPS I, II, and VI. Echocardiography and electrocardiography can provide us good tools for early detection and long-term follow-up for these patients.

Early initiation of enzyme replacement therapy for the mucopolysaccharidoses

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.

Low bone mineral content and challenges in interpretation of dual-energy X-ray absorptiometry in children with mucopolysaccharidosis types I, II, and VI

Osteoporosis has been described in animal models of mucopolysaccharidosis (MPS). Whether clinically significant osteoporosis is common among children with MPS is unknown. Therefore, cross-sectional data from whole body (WB; excluding head) and lumbar spine (LS) bone mineral density (BMD) compared with sex-, chronologic age-, and ethnicity-matched healthy individuals (Zage), height-for-age (HAZ) Z-score (ZHAZ) and bone mineral content (BMC) measured by dual-energy X-ray absorptiometry (DXA) in 40 children with MPS were analyzed. A subset of these children (n=24) was matched 1:3 by age and sex to a group of healthy children (n=72) for comparison of BMC adjusted for Tanner stage, race, lean body mass, height, and bone area. Low BMD Z-score was defined as Z-score of -2 or less. In children with MPS, 15% had low WB Zage and 48% had low LS Zage; 0% and 6% had low WB ZHAZ and low LS ZHAZ, respectively. Adjusted WB BMC was lower in MPS participants (p=0.009). In conclusion, children with MPS had deficits in WB BMC after adjustments for stature and bone area. HAZ adjustment underestimated bone deficits (i.e., overestimated WB BMD Z-scores) in children with MPS likely owing to their abnormal bone shape. The influence of severe short stature and bone geometry on DXA measurements must be considered in children with MPS to avoid unnecessary exposure to antiresorptive treatments.

Respiratory and sleep disorders in mucopolysaccharidosis

MPS encompasses a group of rare lysosomal storage disorders that are associated with the accumulation of glycosaminoglycans (GAG) in organs and tissues. This accumulation can lead to the progressive development of a variety of clinical manifestations. Ear, nose, throat (ENT) and respiratory problems are very common in patients with MPS and are often among the first symptoms to appear. Typical features of MPS include upper and lower airway obstruction and restrictive pulmonary disease, which can lead to chronic rhinosinusitis or chronic ear infections, recurrent upper and lower respiratory tract infections, obstructive sleep apnoea, impaired exercise tolerance, and respiratory failure. This review provides a detailed overview of the ENT and respiratory manifestations that can occur in patients with MPS and discusses the issues related to their evaluation and management.

[Mucopolysaccharidosis and organ of sight]

Mucopolysaccharidoses are a group of genetically determined storage diseases in which lysosomal enzyme deficiency leads to a vast accumulation of glycosaminoglycans in tissues. Depending on the sort of deficient enzyme MPS are divided into the types marked with Roman numerals. Clinical symptoms are caused by the involvement of the nervous, respiratory, visceral and skeletal system, organ of hearing and sight. Ocular manifestations result in significant visual impairment. Ophthalmic symptoms include corneal opacification, glaucoma, optic nerve swelling and retinopathy. Modern methods for the treatment involving enzyme replacement therapy and bone marrow transplantation significantly improved the prognosis in many cases. This article presents a brief description of mucopolysaccharidoses, concentrating mainly on ocular symptoms and their possible treatments.

Dental findings and oral health status in patients with mucopolysaccharidosis: a case series

OBJECTIVE

To present a mucopolysaccharidosis (MPS) case series evaluating oral manifestations (clinical and radiographic), oral health status and discussing its implications.

PATIENTS AND METHODS

All patients with MPS attending the Genetics clinic/Brazil were evaluated by means of anamnesis, clinical and radiographic examinations.

RESULTS

The final sample consisted of 12 subjects (nine males and three females), with ages ranging from 3-31 years old. Concerning oral health, it was observed high levels of caries and periodontal problems. About oral manifestations, this study clinically observed more cases of delayed tooth eruption, thickness of alveolar process and thick lips. Radiographically, it was observed alterations on condyle, mandibular ramus and joint fossa.

CONCLUSION

The dental changes in MPS population are high and consequently it is important to know them for differential diagnoses, early treatment intervention, prevention and education of both patients and parents/caregivers about oral health.

[Ocular findings in children with mucopolysaccharidosis]

OBJECTIVE

to describe the ocular findings in children with mucopolysaccharidosis at the Ophtalmology department.

METHODS

clinical, descriptive, retrospective, transversal, and observational study was done. The cohort included patients under 16 years old, treated at the Hospital General, Centro Médico Nacional La Raza, with diagnosis of mucopolysaccharidosis. The variables were age, gender, damaged eye, visual acuity, ocular findings, type of mucopolysaccharidosis.

RESULTS

there were 11 patients with mucopolysaccharidosis, 10 of them (90.9 %) full filled the inclusion criteria; nine were men. Mean age was 5.5 ± 2.8 years. There were ocular findings in both eyes in 60 % of the patients, 10 % of them in just one eye. The most frequent finding was corneal opacity (70 %), bilateral in 85.7 %, and in a single eye in 14.3 %. The ocular findings (40 %) were common in mucopolysaccharidosis type I.

CONCLUSIONS

there is visual sequels secondary to mucopolysaccharidosis. It is important to study the ocular disorders in order to treat it timely and give to patients the immediate rehabilitation to improve the quality of life.

Carotid intima-media thickness is increased in patients with mucopolysaccharidoses

BACKGROUND

The feasibility of carotid artery intima-media thickness (C-IMT), an established cardiovascular disease marker, as a cardiac risk marker in mucopolysaccharidosis (MPS) patients was explored.

OBJECTIVES

To determine if C-IMT is abnormal in MPS versus unaffected controls, and if C-IMT correlates with coronary artery diameter in MPS.

MATERIAL AND METHODS

Measurements of C-IMT via neck ultrasound and echocardiographic parameters, including coronary artery diameters, were obtained from MPS and control patients, and compared.

RESULTS

Sixteen MPS subjects (6 MPS I, 6 MPS II, 2 MPS III, 1 MPS VI, 1 MPS VII) and sixteen age, ethnicity, and gender-matched controls were enrolled. Median MPS and control subject ages were 8.3±4.5 and 8.6±4.3 years, respectively (p=0.73). Mean MPS and control C-IMTs were 0.54±0.070 and 0.48±0.034 mm (p=0.0029). No differences in left main, left anterior descending, or right coronary artery diameters were seen between MPS and controls. A significant proportion of MPS subjects had mitral insufficiency (14/16; p=0.0002), aortic insufficiency (10/16; p=0.0021), and left ventricular dilatation (7/16, p=0.037) versus controls. C-IMT did not correlate significantly with age, height, weight, coronary measurements, or duration of treatment.

CONCLUSION

C-IMT in MPS patients is increased compared to matched controls, likely reflective of arterial intima-medial glycosaminoglycan accumulation. MPS subjects demonstrated a high percentage of left-sided valvular insufficiency and ventricular dilatation. Additional studies should be performed in MPS patients to determine if C-IMT correlates with arterial elasticity, biomarkers of vascular dysfunction, and higher risk of cardiovascular events.

Mucopolysaccharidoses: anesthetic considerations and clinical manifestations

Mucopolysaccharidosis (MPS) is a group of genetic disorders that presents challenges during anesthetic care and in particular difficulty with airway management. Patients should be managed by experienced anesthesiologists at centers that are familiar with these types of conditions. Rarely encountered disease states have been identified as important topics in the continuing education of clinical anesthesiologists. This review will define MPS, describe the pathophysiology of MPS, describe how patients with this rare lysosomal storage disorders have dysfunction of tissues, cite the incidence of MPS, list the clinical manifestations and specific problems associated with the administration of anesthesia to patients with MPS, present treatment options for patients with MPS, define appropriate preoperative evaluation and perioperative management of these patients, including, to anticipate potential postoperative airway problems.

Sleep-related breathing in children with mucopolysaccharidosis

BACKGROUND

The mucopolysaccharidoses (MPSs), a group of genetic lysosomal storage disorders, are associated with significant morbidity. Secondarily to specific associated anatomical abnormalities, MPS is associated with sleep disordered breathing (SDB), specifically obstructive sleep apnoea (OSA) that may confer additional morbidity. Few studies have examined SDB in children with MPS using full polysomnography (PSG) and thus the exact prevalence and severity of SDB is unknown. Further, successful treatments for SDB in this population have not been explored.

OBJECTIVES

This study evaluated both SDB and the efficacy of treatments offered to children with MPS using PSG data.

PATIENTS AND METHODS

A retrospective chart review was conducted on all children with MPS and a history of suspected OSA who were referred to the Hospital for Sick Children, Toronto. Both baseline and follow up treatment PSG data were analysed. PSG data recorded included obstructive apnoea-hypopnoea index (OAHI) and central apnoea index (CAI).

RESULTS

Fourteen patients (10 male) underwent a baseline PSG. Three of 14 children on ERT were excluded from the main analyses. The median (range) baseline parameters of the population (n = 11) were recorded. The age was 5.2 years (0.8-17.8) and the body mass index (BMI) was 19.9 (13.7-22.2). The OAHI was 6.6 (0.0-54.8); the CAI was 0.6 (0.0-2.6). Seven of 11 (64%) had evidence for OSA and 3/7 children were classified as having severe OSA (OAHI > 10). Of these, 5/7 children underwent treatment for OSA with 3/5 children showing a significant reduction in their OAHI. Further, the 2 patients on ERT therapy with OSA were also both successfully treated.

CONCLUSIONS

Children with MPS have a high prevalence of significant OSA and thus should be carefully screened for OSA using full polysomnography and treated accordingly.