Health-related quality of life in mucopolysaccharidosis: looking beyond biomedical issues

Open-label, single-center, clinical study evaluating the safety, tolerability and clinical effects of pentosan polysulfate sodium in subjects with mucopolysaccharidosis I

Lysosomal enzyme deficiency in mucopolysaccharidosis (MPS) I results in glycosaminoglycan (GAG) accumulation leading to pain and limited physical function. Disease-modifying treatments for MPS I, enzyme replacement, and hematopoietic stem cell therapy (HSCT), do not completely resolve MPS I symptoms, particularly skeletal manifestations. The GAG reduction, anti-inflammatory, analgesic, and tissue remodeling properties of pentosan polysulfate sodium (PPS) may provide disease-modifying treatment for musculoskeletal symptoms and joint inflammation in MPS I following ERT and/or HSCT. The safety and efficacy of PPS were evaluated in four subjects with MPS I aged 14-19 years, previously treated with ERT and/or HSCT. Subjects received doses of 0.75 mg/kg or 1.5 mg/kg PPS via subcutaneous injections weekly for 12 weeks, then every 2 weeks for up to 72 weeks. PPS was well tolerated at both doses with no serious adverse events. MPS I GAG fragment (UA-HNAc [1S]) levels decreased at 73 weeks. Cartilage degradation biomarkers serum C-telopeptide of crosslinked collagen (CTX) type I (CTX-I) and type II (CTX-II) and urine CTX-II decreased in all subjects through 73 weeks. PROMIS scores for pain interference, pain behavior, and fatigue decreased in all subjects through 73 weeks. Physical function, measured by walking distance and dominant hand function, improved at 49 and 73 weeks. Decreased GAG fragments and cartilage degradation biomarkers, and positive PROMIS outcomes support continued study of PPS as a potential disease-modifying treatment for MPS I with improved pain and function outcomes.

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.

Characterization of orthopedic manifestations in patients with mucopolysaccharidosis II using data from 15 years of the Hunter Outcome Survey

Mucopolysaccharidosis II (MPS II) is a rare, life-limiting lysosomal storage disease caused by reduced iduronate-2-sulfatase activity. Patients experience broad ranging signs and symptoms, including bone and joint manifestations. This study reported on orthopedic involvement and management in patients with MPS II using 15 years of data from the Hunter Outcome Survey (HOS). Of the 245 patients in the study population, 90.2% had skeletal deformity (median onset, 2.8 years), 76.7% had upper body stiffness (onset, 4.2 years), and 61.2% had lower body stiffness (onset, 5.3 years); 63.7% of patients had at least three joint manifestations. Orthopedic manifestations were common in adults and children with MPS II, and in patients with and without cognitive impairment. Joint range of motion (JROM) was restricted in all joints assessed (shoulder, elbow, hip, wrist, knee, and ankle). Little correlation was observed between JROM measurements, subjective reports of joint stiffness and limited function, and 6-minute walk test results. Patients with joint stiffness and limited function were generally more likely to have central and peripheral nervous system, pulmonary, and cardiovascular manifestations than those without these symptoms. Carpal tunnel decompression was the most common orthopedic surgery (recorded in 49/245 patients [20.0%]), but orthopedic surgeries were uncommon overall. Our findings highlight the need for routine monitoring of orthopedic manifestations using multiple assessment types in patients with MPS II to help inform clinical decision-making and improve patient quality of life. They also underline the contribution of factors other than orthopedic manifestations to the walking ability of patients with MPS II.

Neuropsychology assessment and outcomes in adult mucopolysaccharidosis - A systematic review as the first step to service development in a large tertiary Lysosomal Storage Disorders centre

A systematic review of Randomised Controlled Trials in adult mucopolysaccharidoses (MPSs) was conducted to inform neuropsychology service development at a large tertiary Lysosomal Storage Diseases centre. Studies including psychological endpoints for cognition, mood, and quality of life were reviewed. Forty-eight studies met the inclusion criteria for full text review. Of the 48 studies, 44% (21/48) included adult participants, while psychological endpoints were used in 52% (25/48) for cognition, 11% (5/48) for mood, and 69% (33/48) for quality of life. Five studies included both adult participants and relevant psychological endpoints. Risk of bias ratings were 'high' for two studies, while two studies received a rating of 'some concerns', and the last study a 'low' risk of bias rating. The evidence base for psychological outcomes in adult MPS disorders is limited and insufficient for guiding neuropsychology service development. Data on the psychosocial effects of MPS across the lifespan will be crucial for planning service development and supporting the neuropsychological needs of adult patients and their families.

Understanding the challenges, unmet needs, and expectations of mucopolysaccharidoses I, II and VI patients and their caregivers in France: a survey study

BACKGROUND

Mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage diseases caused by defective enzyme activity involved in the catalysis of glycosaminoglycans. Published data on adult patients with MPS remains scarce. Therefore, the present qualitative survey study was aimed at understanding knowledge of the disease, unmet needs, expectations, care, and overall medical management of adult/adolescent patients with MPS I, II and VI and their caregivers in France.

RESULTS

A total of 25 patients (MPS I, n_p = 11; MPS II, n_p = 9; MPS VI, n_p = 5) were included and about 36 in-depth interviews (caregivers alone, n_c = 8; patients-caregiver pair, n_c+p = 22; patients alone, n_p = 6) were conducted. Except one (aged 17 years), all patients were adults (median age: 29 years [17-50]) and diagnosed at median age of 4 years [0.4-30], with mainly mothers as caregivers (n_c = 16/19). Patients were classified into three groups: Group A, Patients not able to answer the survey question because of a severe cognitive impairment (n_p = 8); Group B, Patients able to answer the survey question with low or no cognitive impairment and high motor disability (n_p = 10); and Group C, Patients able to answer the survey question with low or no cognitive impairment and low motor disability (n_p = 7). All groups were assessed for impact of disease on their daily lives based on a scale of 0-10. Caregivers in Group A were found to be most negatively affected by the disease, except for professional activity, which was most significantly impacted in Group B (4.7 vs. 5.4). The use of orthopaedic/medical equipments, was more prevalent in Groups A and B, versus Group C. Pain management was one of the global unmet need expressed by all groups. Group A caregivers expected better support from childcare facilities, disability clinics, and smooth transition from paediatric care to adult medicine. Similarly, Group B caregivers expected better specialised schools, whereas Group C caregivers expected better psychological support and greater flexibility in weekly infusion schedules for their patients.

CONCLUSIONS

The survey concluded that more attention must be paid to the psychosocial status of patients and caregivers. The preference for reference centre for follow-up and treatment, hospitalizations and surgeries were evident. The most significant needs expressed by the patients and caregivers include better understanding of the disease, pain management, monitoring of complications, flexibility in enzyme replacement therapy, home infusions especially for attenuated patients, and improved transitional support from paediatric to adult medicine.

Findings from the Morquio A Registry Study (MARS) after 6 years: Long-term outcomes of MPS IVA patients treated with elosulfase alfa

BACKGROUND

The Morquio A Registry Study (MARS) is an ongoing, multinational, observational study of patients with MPS IVA. Key objectives of MARS are to characterize the heterogeneity and natural history of disease and to evaluate long-term effectiveness and safety of elosulfase alfa enzyme replacement therapy (ERT). Enrollment began in September 2014; data on medical history, clinical outcomes, and safety assessments are collected as part of routine care.

RESULTS

As of February 2021, 381 subjects from 17 countries had enrolled in MARS: 58 ERT-naïve subjects and 323 ERT-treated subjects (≥1 infusion), with a mean ERT exposure of 5.5 years (SD 2.8) and median age at first ERT treatment of 9.8 years. ERT-treated subjects were younger at diagnosis (median 3.4 vs 6.5 years) relative to ERT-naïve subjects. Among ERT-treated subjects, urinary keratan sulfate (uKS) levels declined from pre-ERT baseline to last follow-up on treatment (mean % change [95% confidence interval]: -52.5% [-57.5%, -47.4%]; n = 115) and 6-min walk test distance remained stable (mean change: -6.1 [-27.6, 15.5] m; n = 131) over a mean follow-up of 5.5 years. Forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) increased in subjects who were < 18 years of age at ERT initiation (mean change: +0.3 [0.1, 0.4] L and + 0.4 [0.3, 0.5] L; mean follow-up: ∼6 years; n = 82) and were stable in subjects ≥18 years (mean change: 0.0 [-0.0, 0.1] L and 0.0 [-0.1, 0.1] L; mean follow-up: 4.6 years; n = 38). Overall, 148 (47.1%) ERT-treated subjects experienced ≥1 adverse event (AE) and 110 subjects (35%) reported ≥1 serious AE. Drug-related AEs were reported in 39 (12.4%) subjects; the most common were hypersensitivity (9 subjects [2.9%]), urticaria (8 subjects [2.5%]), and pyrexia (7 subjects [2.2%]).

CONCLUSIONS

MARS is the longest and largest observational study of MPS IVA patients to date, with a heterogenous population that is representative of the MPS IVA population overall. Data collected over the first 6 years of MARS provide real-world evidence for long-term stabilization of endurance and respiratory function among ERT-treated patients, with no new safety concerns identified.

Mandibular condyle morphology among patients with mucopolysaccharidosis: An observational study of panoramic radiographs

BACKGROUND

Mucopolysaccharidoses (MPS) are a group of rare metabolic diseases characterized by a wide spectrum of symptoms including progressive condylar resorption.

AIM

The aim of this study was to quantify the severity of condylar involvement in MPS I individuals in comparison with a group of non-MPS individuals and to describe how condylar changes may vary among the different types of MPS.

DESIGN

Fifty panoramic radiographs of MPS patients (13.4 ± 6.2 years) with MPS I (n = 14), MPS II (n = 2), MPS IV (n = 8) and MPS VI (n = 2) were compared with forty panoramic radiographs of non-MPS individuals. The severity of condylar resorption was evaluated using a qualitative score (grades 0-3) and using the ratio of condylar height to ramus height (CH: RH).

RESULTS

All MPS I and VI individuals showed pronounced bilateral degenerative condylar resorption. In contrast, individuals with MPS II and IV exhibited heterogeneous findings. The quantification of condylar height to ramus height revealed that CH: RH was significantly decreased in MPS I as compared to that of non-MPS individuals (P < .001). In contrast, the CH: RH ratios of MPS II and IV showed great variability.

CONCLUSION

Mucopolysaccharidoses subtypes differ with regard to the severity of condylar resorption.

Chest wall volumes, diaphragmatic mobility, and functional capacity in patients with mucopolysaccharidoses

PURPOSE

We investigated respiratory muscle strength, diaphragm mobility, lung function, functional capacity, quality of life, body composition, breathing pattern, and chest wall (V_T,CW) and compartmental volumes of Mucopolysaccharidosis (MPS) patients and compared these variables with matched healthy individuals.

METHODS

A cross-sectional study with data analyzed separately according to age group. A total of 68 individuals (34 MPS and 34 matched-healthy subjects) were included. Six-minute walking test assessed functional capacity and ultrasound assessed diaphragm mobility during quiet spontaneous breathing (QB). Optoelectronic plethysmography assessed V_T,CW and breathing pattern during QB in two different positions: seated and supine (45° trunk inclination).

RESULTS

Body composition, lung function, respiratory muscle strength, and functional capacity were reduced in MPS (all p < 0.01). Diaphragm mobility was only reduced in adolescents (p = 0.01) and correlated with body composition and breathing pattern. Upper chest wall compartmental volumes were significantly lower in MPS, while abdominal volume only differed significantly in adolescents. Percentage contribution (%) of upper ribcage compartments to tidal volume was reduced in MPS children, whereas %AB was significantly increased compared with healthy subjects.

CONCLUSION

Lung function, respiratory muscle strength, functional capacity, diaphragm mobility, and quality of life are reduced in MPS compared with matched healthy subjects. V_T,CW was mainly reduced due to pulmonary and abdominal ribcage impairment. Implications for RehabilitationReduction in respiratory muscle strength, functional capacity, diaphragm excursion and low lung volumes were found in individuals with Mucopolysaccharidoses (MPS).Chest wall volumes and the upper chest wall compartmental volumes during quiet spontaneous breathing are reduced in MPS.Assessment and monitoring of the respiratory system for individuals with MPS should be performed periodically through standardized assessments to enable identification of changes and early intervention by rehabilitation protocols.This study may provide the necessary basis for carrying out respiratoty rehabilitation protocols that can improving chest wall mechanics with breathing exercise in this group.

Consensus statement on enzyme replacement therapy for mucopolysaccharidosis IVA in Central and South-Eastern European countries

BACKGROUND

Mucopolysaccharidosis IVA (MPS IVA), or Morquio A syndrome, is a rare inherited metabolic disorder caused by deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfatase. A progressive systemic skeletal chondrodysplasia, leading to significant morbidity and reduced life expectancy is the main clinical feature of this multisystemic disease. Although enzyme replacement therapy with elosulfase alfa is established in Europe, the rarity of disease and other factors still set hurdles in having patients treated in some countries. Aim of this statement is to provide evidence-based guidance for the enzyme replacement treatment of Morquio A patients, harmonizing recommendations from published guidelines with the real-life clinical practice in the Central and South-Eastern European region.

PARTICIPANTS

The Consensus Group, convened by 8 Steering Committee (SC) members from 7 Central and South-Eastern European countries, consisted of a multidisciplinary group of 17 experts in the management of MPS in Central and South-Eastern Europe.

CONSENSUS PROCESS

The SC met in a first virtual meeting with an external scientific coordinator, to discuss on clinical issues to be analyzed in guidance statements. Statements were developed by the scientific coordinator, evaluated by the SC members in a first modified-Delphi voting and adapted accordingly, to be submitted to the widest audience in the Consensus Conference. Following discussion and further modifications, all participants contributed to a second round of modified-Delphi voting.

RESULTS

Nine of ten statements, concerning general guidelines for management of MPS IVA patients and specific recommendations for treatment, received final consensus.

CONCLUSIONS

European guidelines and evidence-based recommendations for Morquio A patients should be considered in the real life of Central and South-Eastern European countries and adapted to unique clinical practice approaches and criteria for patients' access to treatment and reimbursement in the region.

Pre-operative Considerations in Adult Mucopolysaccharidosis Patients Planned for Cardiac Intervention

Mucopolysaccharidoses (MPS) are rare lysosomal storage diseases characterized by multiorgan involvement and shortened longevity. Due to advances in therapies such as enzyme replacement therapy and haematopoietic stem cell therapy, life expectancy has increased posing newer challenges to patients and health professionals. One such challenge is cardiovascular manifestations of MPS, which can be life limiting and cause reduction in quality of life. Any cardiovascular intervention mandates comprehensive, multi-systemic work-up by specialist teams to optimize outcome. We highlight the importance of multidisciplinary evaluation of adult MPS patients requiring cardiovascular intervention. Clinical assessments and investigations are discussed, with a focus on the cardiac, anesthetic, airway, respiratory, radiological and psychosocial factors.

Non-cardiac Manifestations in Adult Patients With Mucopolysaccharidosis

Mucopolysaccharidoses (MPS) are a heterogeneous group of disorders that results in the absence or deficiency of lysosomal enzymes, leading to an inappropriate storage of glycosaminoglycans (GAGs) in various tissues of the body such as bones, cartilage, heart valves, arteries, upper airways, cornea, teeth, liver and nervous system. Clinical manifestations can become progressively exacerbated with age and affect their quality of life. Developments in advanced supportive treatment options such as enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT) may have improved patients' life span. Adult MPS patients require specialist clinical surveillance long-term. In many cases, in addition to the MPS-related health problems, they may develop age-related complications. Considering the complexity of their clinical manifestations and lack of guidelines on the management of adult MPS disorders, multispecialty and multidisciplinary teams' care is essential to diagnose and treat health problems that are likely to be encountered. This review presents non-cardiac clinical manifestations, their pathophysiology, management and long-term outcomes in adult MPS patients.

Functioning profiles of individuals with Mucopolysaccharidosis according to the International Classification of Functioning

BACKGROUND

The classification of health problems of persons with Mucopolysaccharidosis (MPS) based on the International Classification of Functioning, Disability and Health (ICF) may contribute to better understanding the disease impacts. The ICF is a useful tool to describe disabilities and functioning, especially in diseases with multisystemic involvement.

AIM

To identify and classify the health needs of persons with non-neuronopathic MPS according to the ICF.

DESIGN

A cross-sectional study.

SETTING

Department of Physical Therapy (Federal University, Brazil).

POPULATION

Persons with non-neuronopathic MPS.

METHODS

Semi-structured interviews covering all components of the ICF were conducted to know the patients' perspectives of their health problems (patient-reported outcomes). The speeches were transcribed verbatim and analyzed by researchers to identifying meaningful concepts. Then, the concept units were linked to ICF components and the magnitude of the problem to ICF qualifiers. Data are shown by descriptive statistics and separated into two groups: children and adolescents, and adults.

RESULTS

A total of 60 different ICF categories were used to classify participants' functioning. A total of 28 and 51 categories was necessary to classify the health problems of children and adults, respectively. Additionally, 16 categories related to contextual factors were used, of which eight and 12 were identified as facilitators by children, adolescents, and adults, respectively. The main problems were related to supportive functioning of arms or legs (b7603), pain in the body part (b2801), respiratory functions (b440), and voice functions (b310). Limitations in the activity and participation component were related to walking (d450), fine hand use (d440), washing oneself (d510), and dressing (d540). Recreation and leisure (d920) was restricted to approximately half of the studied population.

CONCLUSIONS

People with MPS face impairments of body structures and functions, activity limitations and restrictions to participation. Environmental factors may be act as facilitators of these problems.

CLINICAL REHABILITATION IMPACT

The ICF is a useful tool to classify the health problems of people with non-neuropathic MPS. The planning of rehabilitation programs needs to covers all components of functioning to provide a biopsychosocial model of care. The ICF categories may direct health professionals to more effective targets.

Mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome): defining and measuring functional impacts in pediatric patients

BACKGROUND

Research about pediatric patients' perspective on mucopolysaccharidosis type VI (MPS VI) and its impact on daily life is limited. We aimed to identify the disease concepts of interest that most impact function and day-to-day life of pediatric patients with MPS VI, and to consider clinical outcome assessments (COAs) that may potentially measure meaningful improvements in these concepts.

METHODS

Potential focus group participants were identified by the National MPS Society (USA) and invited to participate if they self-reported a clinician-provided diagnosis of MPS VI and were 4 to 18 years, receiving enzyme replacement therapy (ERT), and available to attend a 1-day focus group with their caregiver in Dallas, TX, USA. The focus group consisted of a series of polling and open-ended concept elicitation questions and a cognitive debriefing session. The discussion was audio recorded, transcribed verbatim, and analyzed to identify disease concepts of interest and functional impacts most relevant to participants.

RESULTS

Overall, caregivers (n = 9) and patients with MPS VI (n = 9) endorsed that although their children/they receive ERT, residual symptoms exist and impact health-related quality of life. The key disease concepts of interest identified were impaired mobility, upper extremity and fine motor deficits, pain, and fatigue. Pain was unanimously reported by all patients across many areas of the body and impacted daily activity. Key disease concepts were mapped to a selection of pediatric COAs including generic measures such as PROMIS®, PODCI, CHAQ, and PedsQL™. Caregivers endorsed the relevance of PODCI and PROMIS Upper Extremity, Mobility, and Pain items and all patients completed the NIH Toolbox Pegboard Dexterity Test. Additional COAs that aligned with the disease concepts included range of motion, the 2- and 6-min walk tests, timed stair climbs, Bruininks-Oseretsky Test of Motor Proficiency, 2nd edition, grip strength, pain visual analog scale, and the Faces Pain Scale-Revised.

CONCLUSION

An MPS VI focus group of pediatric patients and their caregivers identified impaired mobility, upper extremity and fine motor deficits, pain, and fatigue as key disease concepts of interest. These disease concepts were mapped to existing pediatric COAs, which were provided to the group for endorsement of their relevance.

Clinical features and health-related quality of life in adult patients with mucopolysaccharidosis IVA: the Spanish experience

BACKGROUND

Mucopolysaccharidosis (MPS) IVA or Morquio A syndrome is a progressive and disabling disease characterized by a deficiency of the enzyme N-acetylgalactosamine-6-sulphate sulphatase. Its clinical presentation is very heterogeneous and poorly understood in adults. The aim of this study was to describe the clinical manifestations of MPS IVA in adult patients in Spain and to assess their health-related quality of life (HRQoL).

RESULTS

Thirty-three patients from nine reference centres participated in the study. The median age was 32 (interquartile range [IQR]: 20.5-40.5) years. The phenotype was classical in 54.5% of patients, intermediate in 33.3% of patients, and non-classical in 12.1% of patients. The most common clinical manifestation was bone dysplasia, with a median height of 118 (IQR: 106-136) cm. Other frequent clinical manifestations were hearing loss (75.7%), ligamentous laxity (72.7%), odontoid dysplasia (69.7%), limb deformities that required orthopaedic aids (mainly hip dysplasia and genu valgus) (63.6%), and corneal clouding (60.6%). In addition, 36.0% of patients had obstructive sleep apnoea/hypopnoea syndrome and 33.3% needed non-invasive ventilation. Cervical surgery and varisation osteotomy were the most common surgical interventions (36.4% each). Almost 80% of patients had mobility problems and 36.4% used a wheelchair at all times. Furthermore, 87.9% needed help with self-care, 33.3% were fully dependent, and 78.8% had some degree of pain. HRQoL according to the health assessment questionnaire was 1.43 (IQR: 1.03-2.00) in patients with the non-classical phenotype, but 2.5 (IQR: 1.68-3.00) in those with the classical phenotype. Seven patients were initiated on enzyme replacement therapy (ERT), but two of them were lost to follow-up. Lung function improved in four patients and slightly worsened in one patient. The distance achieved in the six-minute walk test increased in the four patients who could perform it. HRQoL was better in patients treated with elosulfase alfa, with a median (IQR) of 1.75 (1.25-2.34) versus 2.25 (1.62-3.00) in patients not treated with ERT.

CONCLUSIONS

The study provides real-world data on patients with MPS IVA. Limited mobility, difficulties with self-care, dependence, and pain were common, together with poor HRQoL. The severity and heterogeneity of clinical manifestations require the combined efforts of multidisciplinary teams.

Activity of daily living in mucopolysaccharidosis IVA patients: Evaluation of therapeutic efficacy

Background

Mucopolysaccharidosis IVA (MPS IVA, also called Morquio A syndrome) is caused by a deficiency of N‐acetylglucosamine‐6‐sulfate sulfatase (GALNS) and results in skeletal dysplasia symptoms such as short stature and abnormal gait. Treatments include enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT), but the effects are limited depending on the age of initiation and clinical phenotype. Thus, this study aims to assess the effects of treatments on MPS IVA patients compared to untreated MPS IVA patients and an age‐matched control group.

Methods

We used activity of daily living (ADL) survey with 4 sections: “movement,” “movement with cognition,” “cognition,” and “other MPS symptoms.” Lower scores indicate more assistance required. This study included 161 patients, 270 total surveys, and 70 patients with longitudinal data.

Results

We describe 134 severe patients and 25 attenuated patients. ERT and HSCT treatment improved only the “other MPS symptoms” section in severe patients. There were no differences between ERT and HSCT severe patient scores. A 19‐year‐old male patient, who had robust physical training, provided a significant increase in “movement” without treatment, suggesting the importance of exercise.

Conclusion

Overall, this ADL questionnaire has demonstrated validation and reliability in assessing the MPS IVA patients and therapeutic efficacy.

Disease burden, management patterns and multidisciplinary clinical approaches for patients with MPS IVA and VI in selected Latin American Countries

Background

There is a paucity of real-world epidemiological data on patients with mucopolysaccharidoses (MPS) in Latin America. This real-world study assessed the disease burden, management patterns and multidisciplinary clinical approaches for MPS-IVA and MPS-VI patients in Latin America (Colombia, Ecuador, Mexico, Peru).

Methods

Data were collected from physicians/specialists experienced in treating MPS patients between April–June 2020, via an online patient-diary survey.

Results

Overall, 29 physicians/specialists participated in this study. Data from 98 patients were analyzed (MPS-IVA, 71 patients and MPS-VI, 27 patients). Mean age for MPS-IVA patients was 17.5 years and for MPS-VI patients was 11.6 years, and the majority were females (52% and 78%, respectively). MPS-IVA and VI patients presented a high absenteeism from school (55% and 37%, respectively; <18 years age) and workplace (78% and 100%, respectively; >18 years age), indicating an impact of the disease on some aspects of the patients' quality of life. The onset of the first symptom occurred at the age of 3.1 years for MPS-IVA patients and at 1 year for MPS-VI, with delay in diagnosis (3.5–3.9 years from symptom onset) and enzyme replacement therapy (ERT) initiation (1.1–3.6 years from diagnosis). ERT interruptions were observed for MPS-IVA (48%) and MPS-VI patients (44%), with non-availability of medication recorded as the main reason for non-adherence (46% and 60% patients, respectively). ERT showed noticeable treatment benefits in MPS-IVA/VI patients, with stabilization/reduction in complications or the number of surgeries. A multidisciplinary clinical team approach was used for patient management.

Conclusion

The disease burden for MPS-IVA/VI was high in Latin America, with consistent management, treatment and socio-demographic trends throughout the region.

Skeletal Abnormalities and VDR1 Gene Polymorphisms in Mucopolysaccharidosis Patients

Introduction

Articular and bone damage, which is so disabling in Mucopolysaccharidosis (MPS), requires attention as to the explanatory bias of the pathogenetic mechanisms identified to date. The vitamin D receptor (VDR) has been investigated in many studies in correlation with bone metabolism, osteoporosis, and the impaired bone mineral density associated with certain polymorphisms of the VDR gene.

Aim

This study aims to observe whether there is an association between clinical features, phospho-calcium metabolism parameters and the VDR gene polymorphisms in patients with MPS.

Patients and Method

We evaluated six patients with MPS type I, 20 patients with MPS type II, two patients with MPS types IIIA and IIIB and three patients with MPS type IVB. In these patients, phospho-calcium metabolism, markers of bone formation, bone radiographs and bone densitometry were evaluated, as were four polymorphisms of the VDR gene (ApaI, BsmI, FokI and TaqI).

Results

There was a deficiency in 25 hydroxy vitamin D in MPS type I patients at the final evaluation and in MPS type II patients, both at ERT initiation and at the last evaluation. The analysed polymorphisms were not associated with modified calcium-phosphor levels, but some differences were observed regarding the level of 25 OH vitamin D. Thus, in the case of AA polymorphism, all patients have a 25 OH vitamin D deficiency, and one patient with the AA genotype and three with Aa have a 25 OH vitamin D deficiency and secondary hyperparathyroidism due to this deficiency (four patients), all of them having the Bb phenotype.

Conclusion

In MPS patients, vitamin D deficiency is observed, as it is in some patients with secondary hyperparathyroidism, which indicates vitamin D supplementation to protect bone metabolism. There are no obvious correlations between VDR polymorphism and bone metabolism in MPS patients.

Oral health of Brazilian individuals with mucopolyssaccaridosis

PURPOSE

This study described and compared the oral characteristics of Brazilian individuals with mucopolysaccharidosis (MPS) and without MPS.

METHODS

A cross-sectional study was performed with 29 individuals with MPS and 29 without MPS and their parents/guardians. The individuals were aged between 3 and 21 years and attended at two hospitals in Belo Horizonte, southeastern Brazil. The dental characteristics were evaluated by clinical examination of dental caries, gingivitis, malocclusion, dental anomalies and developmental defects of enamel. The parents/guardians answered a questionnaire about the sociodemographic and behavioural aspects of their children. The study was approved by the Research Ethics Committee of the Federal University of Minas Gerais.

RESULTS

The average age of the individuals was 13.9 years (± 7.2). The majority were male (58.6%), had black/brown skin (70.7%) and were from favored economic class (89.7%). Dental caries, gingivitis, malocclusion and dental anomalies were more prevalent in the MPS group (p < 0.05).

CONCLUSION

The individuals with MPS had a higher prevalence of oral diseases and dental anomalies than the group without MPS.

Impact of long-term elosulfase alfa treatment on clinical and patient-reported outcomes in patients with mucopolysaccharidosis type IVA: results from a Managed Access Agreement in England

Background

We present baseline characteristics and follow-up data of a Managed Access Agreement (MAA), including patients with mucopolysaccharidosis IVA (MPS IVA) receiving elosulfase alfa enzyme replacement therapy (ERT) in England on a conditional basis. Patients enrolled in the MAA programme are reviewed on an annual basis. Therapy can be continued if patients are compliant, able to tolerate infusions, and meet four out of five pre-defined clinical and patient-reported outcomes (PRO) criteria. Baseline and follow-up clinical and PRO data are presented for all participants who completed ≥ 1 year of assessments in the MAA.

Results

The analysis included data from 55 patients, including 26 patients previously enrolled in clinical trials and 29 who started ERT after enrolling in the MAA. In patients with both baseline and follow-up data, mean 6-min walk test distance increased from 217 m at baseline to 244 m after a mean follow-up of 4.9 years. Improvement or stabilisation was seen regardless of age at treatment initiation or duration of treatment. Mean forced vital capacity and forced expiratory volume in 1 s were 0.87 L and 0.78 L, respectively at baseline and 1.05 L and 0.88 L after a mean follow-up of 5.5 years. PRO data showed overall improvements over time in Mobility, Self-care, and Caregiver assistance scores of the MPS-Health Assessment Questionnaire, relatively stable quality of life, and some improvements in pain scores.

Conclusions

The MAA data confirm the effects of elosulfase alfa on clinical and PRO results observed in the clinical trials and provide real-world evidence for long-term stabilisation in these measures, suggesting a positive impact on the natural history of MPS IVA.

Therapy development for the mucopolysaccharidoses: Updated consensus recommendations for neuropsychological endpoints

Neurological dysfunction represents a significant clinical component of many of the mucopolysaccharidoses (also known as MPS disorders). The accurate and consistent assessment of neuropsychological function is essential to gain a greater understanding of the precise natural history of these conditions and to design effective clinical trials to evaluate the impact of therapies on the brain. In 2017, an International MPS Consensus Panel published recommendations for best practice in the design and conduct of clinical studies investigating the effects of therapies on cognitive function and adaptive behavior in patients with neuronopathic mucopolysaccharidoses. Based on an International MPS Consensus Conference held in February 2020, this article provides updated consensus recommendations and expands the objectives to include approaches for assessing behavioral and social-emotional state, caregiver burden and quality of life in patients with all mucopolysaccharidoses.

Intravenous Enzyme Replacement Therapy in Mucopolysaccharidoses: Clinical Effectiveness and Limitations

The aim of this review is to summarize the evidence on efficacy, effectiveness and safety of intravenous enzyme replacement therapy (ERT) available for mucopolysaccharidoses (MPSs) I, II, IVA, VI and VII, gained in phase III clinical trials and in observational post-approval studies. Post-marketing data are sometimes conflicting or controversial, possibly depending on disease severity, differently involved organs, age at starting treatment, and development of anti-drug antibodies (ADAs). There is general agreement that ERT is effective in reducing urinary glycosaminoglycans and liver and spleen volume, while heart and joints outcomes are variable in different studies. Effectiveness on cardiac valves, trachea and bronchi, hearing and eyes is definitely poor, probably due to limited penetration in the specific tissues. ERT does not cross the blood-brain barrier, with the consequence that the central nervous system is not cured by intravenously injected ERT. All patients develop ADAs but their role in ERT tolerance and effectiveness has not been well defined yet. Lack of reliable biomarkers contributes to the uncertainties about effectiveness. The data obtained from affected siblings strongly indicates the need of neonatal screening for treatable MPSs. Currently, other treatments are under evaluation and will surely help improve the prognosis of MPS patients.

Assessing the impact of the five senses on quality of life in mucopolysaccharidoses

Background

The mucopolysaccharidoses (MPSs) are lysosomal storage disorders associated with progressive multi-organ and skeletal abnormalities. Clinical manifestations can affect each of the five senses: hearing, vision, smell, taste, and touch.

Main body of the abstract

On 24–26 May 2018, 46 specialists with expertise in managing symptoms of MPS and experts specialized in evaluating and managing impairments in each one of the five senses gathered in Lisbon, Portugal at the “MPS & the five senses” meeting to discuss how loss of one or multiple senses can affect activities of daily living (ADL) and quality of life (QoL) in MPS patients and best practices in evaluating and managing the loss of senses in these individuals. The meeting confirmed that MPS can affect the senses considerably, but how these impairments affect ADL and overall QoL from a patient’s perspective remains unclear. A better insight may be achieved by prospectively collecting patient-reported outcome (PRO) data internationally in a standardized way, using a standard battery of tools. To identify relevant PRO tools, a systematic literature review and a selection of existing published questionnaires, focused on adults with no intellectual delay, were performed after the meeting. The search strategy identified 33 PRO tools for hearing, 30 for speech, 125 for vision, 49 for touch (including pain and upper limb function), and 15 for smell/taste. A further selection was made based on several criteria, including applicability/relevance for MPS, applicability in different countries (languages)/cultures, availability in English, ease of use, validation, and normative data, resulting in a final set of 11 tools. In addition to these sense-specific PRO tools, a general QoL tool, the EuroQol (EQ)-5D-5 L, was selected to assess overall QoL and reveal coping behaviors.

Short conclusion

MPS can affect each of the five senses, but current knowledge on the impact of sense impairments on QoL/ADL in MPS patients remains limited. Collection of data in a standardized fashion using sense-specific patient-reported outcome tools and a general QoL tool may fill the current knowledge gap.

Pathway to diagnosis and burden of illness in mucopolysaccharidosis type VII - a European caregiver survey

Background

Mucopolysaccharidosis type VII (Sly disease, MPS VII), is an ultra-rare, multi-symptom disease with variable clinical presentations which can present challenges with diagnosis, management and care. We believe this survey is the first to explore the patient experience through direct questioning of the caregivers of 13 individuals with MPS VII.

Methods

This European survey, using a specifically designed questionnaire, was conducted in order to describe the pathway to diagnosis and the burden of illness of MPS VII. Information on early symptoms, clinicians seen, and current symptoms was collected. Questions on the caregivers’ ability to work and the use and availability of health, social and educational support were included.

Results

Caregivers of 13 patients from Germany, Spain, The Netherlands and Turkey responded to the survey. Five patients with non-immune hydrops fetalis (NIHF) were diagnosed with MPS VII at a mean age of 1.9 years (median 0.3 years, range 0.2 to 6 years). Those without NIHF (n = 7) were diagnosed at a mean age of 6.1 years (median 6.0 years, range 1.9 to 14 years). The symptoms most likely to raise a suspicion of MPS VII, excluding NIHF, did not appear until a median age of at least three years.

Over one half of patients required assistance with daily living and mobility. Reduction of the working hours of caregivers was often necessary (46.2% reduced hours, 30.8% stopped working).

Patients attended frequent medical appointments (12.7/year), over 80% had surgery and 30% had been hospitalised for respiratory issues.

While support for learning and behavioural needs was generally available, support for mobility was not available to 50% of patients. Half of the respondents (6/12) said they were not offered genetic counselling.

Conclusions

For children that do not present with NIHF, diagnosis can take several years as early symptoms can be non-specific and mistaken for other conditions. Increased awareness of the early signs of disease and more information for parents/caregivers at diagnosis are needed. MPS VII poses significant burden to patients, caregivers, healthcare, social and educational services. Access to information and support varies across Europe and the availability of genetic counselling is limited in some countries.

Individual heat map assessments demonstrate vestronidase alfa treatment response in a highly heterogeneous mucopolysaccharidosis VII study population

Mucopolysaccharidosis (MPS) VII is an ultra-rare, progressively debilitating, life-threatening lysosomal disease caused by deficiency of the enzyme, β-glucuronidase. Vestronidase alfa is an approved enzyme replacement therapy for MPS VII. UX003-CL301 was a phase 3, randomized, placebo-controlled, blind-start study examining the efficacy and safety of vestronidase alfa 4 mg/kg intravenously administered every 2 weeks to 12 patients with MPS VII. Due to the rarity of disease, broad eligibility criteria resulted in a highly heterogeneous population with variable symptoms. For an integrated view of the diverse data, the changes from baseline (or randomization for the placebo period) in clinical endpoints were grouped into three functional domains (mobility, fatigue, and fine motor + self-care) and analyzed post-hoc as subject-level heat maps. Mobility assessments included the 6-minute walk test, 3-minute stair climb test, Bruininks-Oseretsky test (BOT-2) gross motor function subtests, and patient-reported outcome assessments (PROs) related to movement, pain, and ambulation. Fatigue assessments included the Pediatric Quality of Life Multidimensional Fatigue Scale and other fatigue-related PROs. Fine motor + self-care assessments included BOT-2 fine motor function subtests and PROs for eating, dressing, hygiene, and caregiver assistance. Most subjects showed improvement in at least one domain. Two subjects improved in two or more domains and two subjects did not show clear improvement in any domain. Both severely and mildly affected subjects improved with vestronidase alfa in clinical assessments, PRO results, or both. Heat map analysis demonstrates how subjects responded to treatment across multiple domains, providing a useful visual tool for studying rare diseases with variable symptoms.

Analysis of the caregiver burden associated with Sanfilippo syndrome type B: panel recommendations based on qualitative and quantitative data

BACKGROUND

Sanfilippo syndrome type B (Sanfilippo B) belongs to a group of rare lysosomal storage diseases characterized by progressive cognitive decline from an early age, acute hyperactivity, and concomitant somatic symptoms. Caregivers face a unique set of challenges related to the complex nature of Sanfilippo B, but the burden and impact on quality of life (QoL) of caregivers is poorly defined and best practice guidance for clinicians is lacking.

METHODS

An international clinical advisors meeting was convened to discuss key aspects of caregiver burden associated with Sanfilippo B based on findings from qualitative and quantitative research undertaken to identify and quantify the nature and impact of the disease on patients and caregivers.

RESULTS

Providing care for patients with Sanfilippo B impinges on all aspects of family life, evolving as the patient ages and the disease progresses. Important factors contributing toward caregiver burden include sleep disturbances, impulsive and hyperactive behavior, and communication difficulties. Caregiver burden remained high throughout the life of the patient and, coupled with the physical burden of daily care, had a cumulative impact that generated significant psychological stress.

CONCLUSION

A Sanfilippo-specific QoL questionnaire is needed that is directed at caregiver needs and burden and best practice management of these domains.

Assessing a possible vulnerability to dental caries in individuals with rare genetic diseases that affect the skeletal development

Background

Individuals diagnosed with a rare genetic disease that affects skeletal development often have physical limitations and orofacial problems that exert an impact on oral health. The aim of the present study was to analyze the possible vulnerability to dental caries in individuals with rare genetic diseases that affect skeletal development.

Methods

A paired cross-sectional study was carried out with a sample of 140 individuals [70 with rare genetic diseases affecting skeletal development: mucopolysaccharidosis (MPS) (n = 29) and osteogenesis imperfecta (OI) (n = 41) and 70 without rare diseases] and their parents/caregivers. The participants in the first group were recruited from two reference hospitals specialized in rare genetic diseases in the city of Belo Horizonte, Brazil. All participants were examined for the evaluation of breathing type, malocclusion, dental anomalies, oral hygiene and dental caries. The parents/caregivers answered a structured questionnaire addressing the individual/behavioral characteristics and medical/dental history of the participants. Statistical analysis involved the chi-square test and multiple logistic regression analysis for the dependent variable (dental caries) (α = 5%). This study received approval from the Human Research Ethics Committee of the Universidade Federal de Minas Gerais.

Results

The mean age of the individuals was 10.34 ± 6.55 years (median: 9.50 years). Individuals with inadequate oral hygiene were 4.70–fold more likely to have dental caries (95% CI: 2.13–10.40) and those with the rare genetic diseases (MPS/OI) were 2.92-fold more likely to have dental caries (95% CI: 1.38–6.17).

Conclusion

Individuals with inadequate oral hygiene and those with MPS and OI had a greater chance of belonging to the group with dental caries. Based on the present findings, individuals with the rare genetic diseases may be considered vulnerable to caries.

Recommendations for the management of MPS IVA: systematic evidence- and consensus-based guidance

INTRODUCTION

Mucopolysaccharidosis (MPS) IVA or Morquio A syndrome is an autosomal recessive lysosomal storage disorder (LSD) caused by deficiency of the N-acetylgalactosamine-6-sulfatase (GALNS) enzyme, which impairs lysosomal degradation of keratan sulphate and chondroitin-6-sulphate. The multiple clinical manifestations of MPS IVA present numerous challenges for management and necessitate the need for individualised treatment. Although treatment guidelines are available, the methodology used to develop this guidance has come under increased scrutiny. This programme was conducted to provide evidence-based, expert-agreed recommendations to optimise management of MPS IVA.

METHODS

Twenty six international healthcare professionals across multiple disciplines, with expertise in managing MPS IVA, and three patient advocates formed the Steering Committee (SC) and contributed to the development of this guidance. Representatives from six Patient Advocacy Groups (PAGs) were interviewed to gain insights on patient perspectives. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with experience managing patients with MPS IVA and the manuscript was evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers.

RESULTS

A total of 87 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) disease-modifying interventions (enzyme replacement therapy [ERT] and haematopoietic stem cell transplantation [HSCT]); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions (including spinal, limb, ophthalmic, cardio-thoracic and ear-nose-throat [ENT] surgeries). Consensus was reached on all statements after two rounds of voting. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance).

CONCLUSION

This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS IVA and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

Quality of life in mucopolysaccharidoses: construction of a specific measure using the focus group technique

OBJECTIVE

To describe the perceptions of patients, their caregivers, and their healthcare providers to the development of a new specific instrument for assessment of the quality of life (QoL) in patients with mucopolysaccharidoses (MPS) using a qualitative focus group (FG) design. FGs were held in two Brazilian states (Rio Grande do Sul and Rio de Janeiro).

RESULTS

Three versions of the new instrument were developed, each for a different age group: children (age 8-12 years), adolescents (age 13-17), and adults (age ≥ 18). The FGs mostly confirmed the relevance of items. All FGs unanimously agreed on the facets: School, Happiness, Life Prospects, Religiosity, Pain, Continuity of Treatment, Trust in Treatment, Relationship with Family, Relationship with Healthcare Providers, Acceptance, and Meaning of Life. The overall concept of QoL (as proposed by the WHO-World Health Organization) and its facets apply to this patient population. However, other specific facets-particularly concerning clinical manifestations and the reality of the disease-were suggested, confirming the need for the development of a specific QoL instrument for MPS.

Psychometric validation of the SF-36 Health Survey in light chain amyloidosis: results from community-based and clinic-based samples

Background

Light chain (AL) amyloidosis, a rare and life-threatening protein misfolding disorder, causes organ damage and severely impacts health-related quality of life (HRQoL). No patient-reported outcome (PRO) HRQoL measure has been validated for use in an AL amyloidosis patient population, leaving a gap for researchers conducting observational studies and clinical trials for drug development. The SF-36 Health Survey (SF-36) has been the most frequently used PRO in AL amyloidosis studies to date, and early qualitative validation studies support its use in this population. The aim of this study was to assess the psychometric properties of the SF-36 among patients with AL amyloidosis.

Methods

Data from community-based (n=341) and clinic-based (n=1,438) observational studies were used to document the psychometric properties of the SF-36 in this disease population. Reliability was estimated using internal consistency (Cronbach’s alpha) and test–retest reliability (intraclass correlation). Convergent validity, known-groups validity, and the ability to detect change were assessed with available criterion variables.

Results

Scale reliability (Cronbach’s alpha ≥0.780 for all scores) and test–retest reliability (intraclass correlation coefficients ≥0.731 for all) were acceptable. Scale convergent validity was supported by strong correlations with conceptually related measures. Mean SF-36 scores varied by response to treatment (P<0.05 for all scores) and a self-reported measure of disease severity (P<0.001 for all scores). Data indicate that the SF-36 is sensitive to changes in other measures over time.

Conclusion

This study provided clear and consistent evidence of the psychometric properties of the SF-36 in both community-based and clinic-based samples of patients with AL amyloidosis.

Does orthopaedic surgery improve quality of life and function in patients with mucopolysaccharidoses?

PURPOSE

Mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders associated with involvement of multiple organs along with a generalised skeletal dysplasia. Both haematopoetic stem cell transplant and enzyme replacement therapy have improved the outlook for patients while surgery remains high-risk and there is little information on clinical or functional outcome to justify many of the surgical procedures performed. This paper aims to summarise the orthopaedic surgical procedures in MPS patients for which quality of life (QoL) and functional data are available and to describe additional QoL and functional measurement tools of relevance to the assessment of orthopaedic outcomes in MPS.

METHODS

We reviewed the available literature to look for reported outcomes of orthopaedic surgery to lower and upper limbs and the spine. In addition, we describe the general and MPS-specific health measures that might be of relevance to the orthopaedic surgeon.

RESULTS

There is some evidence in the literature that orthopaedic surgery may improve QoL and function in some specific aspects of the MPS condition (in relation to genu valgum, carpal tunnel syndrome and trigger digits); however, the literature is sparse and consists of level 4/5 studies only. Further studies of these conditions should include QoL and functional assessment in order to confirm or refute these reports. In other areas (spine and hip), outcomes are judged largely on radiographic appearances with little clinical correlation and short follow-up; however, one long-term study of function following hip dysplasia surgery suggests poor outcomes. Anaesthetic morbidity/mortality is not insignificant in these complex patients with multi-organ involvement. Careful assessment is required, particularly when there is neurological involvement.

CONCLUSIONS

Orthopaedic surgeons involved with MPS patients should be encouraged to use and report measures of QoL and function with respect to musculoskeletal manifestations and response to surgery, recognising that such assessments in these complex and challenging patients may require a multidisciplinary approach.

Mucopolysaccharidoses seen in adults in rheumatology

Mucopolysaccharidoses are a group of rare lysosomal storage diseases including a great number of polymorph syndromes, each being related to a particular mutation responsible for a deficiency of glycosaminoglycan degrading enzymes, leading to an accumulation of glycosaminoglycans in tissues. Many of them are diagnosed in children or teenagers and have a severe prognosis because of organ failure, and are consequently usually not seen by the adult rheumatologist. However, some of them have a more progressive presentation, with musculoskeletal symptoms at the forefront and a lifespan that nearly reaches that of the general population. These milder forms are more likely to be diagnosed in adults, in patients who have suffered for years and sometimes even decades with unrecognized mucopolysaccharidosis. Indeed, they can sometimes mimic inflammatory rheumatic disorders, and therefore be misdiagnosed for a long time. Recognition and diagnosis of these attenuated forms can be a real challenge as they lead to moderate and/or nonspecific symptoms such as joint pain or stiffness. Hence, rheumatologists should know about them. Early diagnostic is essential since specific treatment, like enzyme replacement therapy, is now available for some subtypes and might, if given early, slow down the development of tissue damage, which is unfortunately irreversible. This article provides the opportunity to review the main clinical and radiographic features, the diagnostic strategy and the update of management, which should be multidisciplinary and led by an experienced physician in a reference centre. The contribution of the rheumatologist is important to ensure symptom control and prevent complications.

The burden of amyloid light chain amyloidosis on health-related quality of life

Background

Light chain (AL) amyloidosis is a rare disease characterized by misfolded amyloid protein deposits in tissues and vital organs, and little is known about the burden of AL amyloidosis on health-related quality of life. This study aimed to quantify the burden of AL amyloidosis in terms of health-related quality of life in a diverse, community-based sample of AL amyloidosis patients.

Results

The SF-36v2® Health Survey (SF-36v2), a widely used generic measure of health-related quality of life (using physical and mental summary scales and subscales assessing eight aspects of functioning and well-being), was administered as an online survey of AL amyloidosis patients with AL amyloidosis (ClinicalTrials.gov, NCT02574676; n = 341). Compared with adjusted general population sample norms, health-related quality of life of AL amyloidosis patients was significantly worse across all SF-36v2 scales and summary measures based on analysis of variance (p < 0.05 for all). The largest decrement in AL amyloidosis patients was related to General Health (Δ = 9.7; p < 0.001). With the exception of Bodily Pain and Mental Health, differences were also clinically meaningful based on established clinically minimal important differences. The burden of AL amyloidosis overall and in key subgroups tended to be greater on physical health than on mental health. Stratified analyses indicated additional burden among patients with recently diagnosed disease and those with cardiac involvement than among their respective counterparts.

Conclusion

Understanding the burden of AL amyloidosis highlights the unmet need for treatment, helps physicians identify ancillary treatments and services geared towards improving patients’ functioning, well-being, and overall health-related quality of life. These findings also help to support the use of health-related quality of life end points as important outcome measures in current and future treatment studies.

Trial registration

ClinicalTrials.gov, NCT02574676. Registered October 5, 2015.