Clearance of heparan sulfate in the brain prevents neurodegeneration and neurocognitive impairment in MPS II mice.

Mucopolysaccharidosis II (MPS II), a lysosomal storage disease caused by mutations in iduronate-2-sulfatase (IDS), is characterized by a wide variety of somatic and neurologic symptoms. The currently approved intravenous enzyme replacement therapy with recombinant IDS (idursulfase) is ineffective for CNS manifestations due to its inability to cross the blood-brain barrier (BBB). Here, we demonstrate that the clearance of heparan sulfate (HS) deposited in the brain by a BBB-penetrable antibody-enzyme fusion protein prevents neurodegeneration and neurocognitive dysfunctions in MPS II mice. The fusion protein pabinafusp alfa was chronically administered intravenously to MPS II mice. The drug reduced HS and attenuated histopathological changes in the brain, as well as in peripheral tissues. The loss of spatial learning abilities was completely suppressed by pabinafusp alfa, but not by idursulfase, indicating an association between HS deposition in the brain, neurodegeneration, and CNS manifestations in these mice. Furthermore, HS concentrations in the brain and reduction thereof by pabinafusp alpha correlated with those in the cerebrospinal fluid (CSF). Thus, repeated intravenous administration of pabinafusp alfa to MPS II mice decreased HS deposition in the brain, leading to prevention of neurodegeneration and maintenance of neurocognitive function, which may be predicted from HS concentrations in CSF.

Intrafamilial variability in the clinical manifestations of mucopolysaccharidosis type II: Data from the Hunter Outcome Survey (HOS).

Several cases of phenotypic variability among family members with mucopolysaccharidosis type II (MPS II) have been reported, but the data are limited. Data from patients enrolled in the Hunter Outcome Survey (HOS) were used to investigate intrafamilial variability in male siblings with MPS II. As of July 2015, data were available for 78 patients aged ≥5 years at last visit who had at least one affected sibling (39 sibling pairs). These patients were followed prospectively (i.e., they were alive at enrollment in HOS). The median age at the onset of signs and symptoms was the same for the elder and younger brothers (2.0 years); however, the younger brothers were typically diagnosed at a younger age than the elder brothers (median age, 2.5 and 5.1 years, respectively). Of the 39 pairs, eight pairs were classified as being discordant (the status of four or more signs and symptoms differed between the siblings); 21 pairs had one, two, or three signs and symptoms that differed between the siblings, and 10 pairs had none. Regression status of the majority of the developmental milestones studied was generally concordant among siblings. Functional classification, a measure of central nervous system involvement, was the same in 24/28 pairs, although four pairs were considered discordant as functional classification differed between the siblings. Overall, this analysis revealed similarity in the clinical manifestations of MPS II among siblings. This information should help to improve our understanding of the clinical presentation of the disease, including phenotype prediction in affected family members.

Cognitive and behaviour profiles of children with mucopolysaccharidosis Type II.

Mucopolysaccharidosis Type II (MPS II) or Hunter Syndrome is a rare X-linked condition, due to a defect in a lysosomal enzyme involved in the breakdown of glycosaminoglycans. It is a progressive condition with worsening over time; however, symptom severity and progression rates vary. Normal intellectual function has been reported in males with mild MPS II but few studies are available that provide comprehensive cognitive profiles. Enzyme replacement therapy (ERT) can stabilize physical symptoms and has become standard treatment. Whether ERT can influence cognition is currently unknown. Considering this, we conducted cognitive, fine motor, and behavioural assessments with three males (7;6-12;1 years) with mild MPS II before and after ERT. Generally, cognition, fine motor skills, and behaviour were in the normal range; however, specific deficits in attention and executive function were identified. Following ERT, some memory improvements were seen. Executive deficits remained, and processing speed declined over time.

Genotype-phenotype relationship in mucopolysaccharidosis II: predictive power of IDS variants for the neuronopathic phenotype.

AIM: Mucopolysaccharidosis type II (MPS II) is caused by variants in the iduronate-2-sulphatase gene (IDS). Patients can be either neuronopathic with intellectual disability, or non-neuronopathic. Few studies have reported on the IDS genotype-phenotype relationship and on the molecular effects involved. We addressed this in a cohort study of Dutch patients with MPS II. METHOD: Intellectual performance was assessed for school performance, behaviour, and intelligence. Urinary glycosaminoglycans were quantified by mass spectrometry. IDS variants were analysed in expression studies for enzymatic activity and processing by immunoblotting. RESULTS: Six patients had a non-neuronopathic phenotype and 11 a neuronopathic phenotype, three of whom had epilepsy. Total deletion of IDS invariably resulted in the neuronopathic phenotype. Phenotypes of seven known IDS variants were consistent with the literature. Expression studies of nine variants were novel and showed impaired IDS enzymatic activity, aberrant intracellular processing, and elevated urinary excretion of heparan sulphate and dermatan sulphate irrespective of the MPS II phenotype. INTERPRETATION: We speculate that very low or cell-type-specific IDS residual activity is sufficient to prevent the neuronal phenotype of MPS II. Whereas the molecular effects of IDS variants do not distinguish between MPS II phenotypes, the IDS genotype is a strong predictor.

Cognitive, medical, and neuroimaging characteristics of attenuated mucopolysaccharidosis type II.

UNLABELLED: The phenotype of attenuated mucopolysaccharidosis type II (MPS II), also called Hunter syndrome, has not been previously studied in systematic manner. In contrast to the "severe" phenotype, the "attenuated" phenotype does not present with behavioral or cognitive impairment; however, the presence of mild behavior and cognitive impairment that might impact long-term functional outcomes is unknown. Previously, significant MRI abnormalities have been found in MPS II. Recent evidence suggests white matter abnormalities in many MPS disorders. METHODS: As the initial cross-sectional analysis of a longitudinal study, we studied the association of brain volumes and somatic disease burden with neuropsychological outcomes, including measures of intelligence, memory, and attention in 20 patients with attenuated MPS II with a mean age of 15.8. MRI volumes were compared to 55 normal controls. RESULTS: While IQ and memory were average, measures of attention were one standard deviation below the average range. Corpus callosum volumes were significantly different from age-matched controls, differing by 22%. Normal age-related volume increases in white matter were not seen in MPS II patients as they were in controls. Somatic disease burden and white matter and corpus callosum volumes were significantly associated with attention deficits. Neither age at evaluation nor age at starting treatment predicted attention outcomes. CONCLUSIONS: Despite average intelligence, attention is compromised in attenuated MPS II. Results confirm an important role of corpus callosum and cortical white matter abnormality in MPS II as well as the somatic disease burden in contributing to attention difficulties. Awareness by the patient and caregivers with appropriate management and symptomatic support will benefit the attenuated MPS II patient.

Health-Related Quality of Life in Patients with MPS II.

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a chronic and progressive X-linked lysosomal disease that mainly affects males. The National MPS Society (2013) reports that MPS II affects 1 in 100,000 to 1 in 150,000 males worldwide. Two distinct forms of the disease are based on age of onset and clinical course: attenuated and severe. MPS II affects many organ systems including the nervous, cardiovascular, gastrointestinal and respiratory systems. Clinical manifestations can include progressive hearing loss, mental impairment, and enlarged liver and spleen. This study focuses on the health-related quality of life of individuals (HRQOL) with MPS II as measured by the parent and self-report versions of the Pediatric Quality of Life Inventory (PedsQL™). Both parents of patients with MPS II as well as patients themselves reported lower scores on all domains of the PedsQL™ (physical, emotional, social and school functioning) indicating that children with MPS II have an overall lower HRQOL when compared to a healthy sample. When compared with patients with other chronic illnesses (cancer, MSUD, galactosemia,), the MPS II sample had significantly lower scores on a number of PedsQL™ scales, suggesting an overall lower HRQOL. No significant relationships were found using scores from parent or self report PedsQL™ measures and length of time on ERT.

Long-term experience with enzyme replacement therapy (ERT) in MPS II patients with a severe phenotype: an international case series.

INTRODUCTION: No published clinical trial data are available to inform the use of enzyme replacement therapy (ERT) in patients with the severe (neuropathic) phenotype of mucopolysaccharidosis II (MPS II). Current guidelines recommend ERT administered intravenously be used on a trial basis in this population. AIMS/METHODS: A retrospective chart review was conducted at five international centers for this case series of 22 patients with neuropathic MPS II who received intravenous idursulfase 0.5 mg/kg weekly for at least 2 consecutive years. We collected data about urinary glycosaminoglycan levels, adverse events, and the following somatic signs/symptoms: skeletal disease, joint range of motion, liver/spleen size, respiratory infections, cardiac disease, diarrhea, skin/hair texture, and hospitalizations. RESULTS: The age at diagnosis was 2 months to 5 years, and the age at idursulfase initiation was between 18 months and 21 years. One of 22 patients experienced improvements in seven somatic signs/symptoms; 17/22 experienced improvements in five to six somatic signs/symptoms; and 4/22 experienced improvements in four somatic signs/symptoms. None experienced fewer than four improvements. No new safety concerns arose. Infusion-related reactions were experienced by 4/22 patients but were successfully managed using accepted strategies. CONCLUSIONS: Long-term treatment with idursulfase was associated with improvements in somatic manifestations in this case series of patients with neuropathic MPS II. The family and medical team should maintain open lines of communication to make treatment decisions that take into consideration the benefits and limitations of ERT in this population.

The Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) Questionnaire: item reduction and further validation.

PURPOSE: The Hunter Syndrome-Functional Outcomes for Clinical Understanding Scale (HS-FOCUS) Questionnaire is a patient and parent-completed disease-specific instrument used in Hunter syndrome (mucopolysaccharidosis II), a rare paediatric progressive multi-systemic lysosomal storage disease. The objective of this study was to shorten the number of items of the Questionnaire to reduce response burden while maintaining its content validity. METHODS: Data collected in a clinical trial were used. An iterative process helped identifying redundant or low performing items based on content validity and psychometric properties. Validation on the retained items was assessed using patients and parent's responses in terms of reliability, validity and responsiveness. RESULTS: The HS-FOCUS was completed by 49 patients and 84 parents. Items were mainly removed owing to high floor effects, high inter-item correlations (>0.80) or inadequate content. The shortened patient and parent versions (18 and 21 items) each contained five function domains. Internal consistency and test-retest reliability were >0.70 for most domains, except Breathing and School/work. Concurrent validity was demonstrated by significant correlations (>0.30) with similar concepts of previously validated measures. Significant differences were found in all domain scores across levels of disability. CONCLUSIONS: The shortened HS-FOCUS is a reliable, valid and responsive measure, where burden in answering the Questionnaire was reduced without compromising its validity.

MPS II: adaptive behavior of patients and impact on the family system.

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a chronic and progressive X-linked lysosomal disease that mainly affects males. It occurs in 1 in every 65,000 to 1 in 132,000 births. There are two distinct forms of the disease based on age of onset and clinical course: mild and severe. MPS II affects many organ systems including the nervous, cardiovascular, gastrointestinal and respiratory systems. Complications can include vision problems, progressive hearing loss, thickened and elastic skin, mental impairment, and enlarged liver and spleen. We herein focus on the adaptive behavior of individuals with MPS II, and the impact of MPS II on the family system. Outcomes from the Vineland-II Adaptive Behavior Scales showed that the MPS II patient sample experienced significantly lower functioning in communication, daily living skills, socialization, and motor skills compared to normative data. Patients with severe MPS II were found to have significantly lower adaptive functioning in all domains, as compared to those with mild MPS II. Length of time on ERT had no significant relationship to adaptive functioning. Results from the Peds QL Family Impact Module indicated that families of patients with MPS II experienced a lower overall health-related quality of life and overall lower family functioning (including lower emotional and cognitive functioning) than those with chronic illnesses residing in an inpatient setting.

The Hunter syndrome-functional outcomes for clinical understanding scale (HS-FOCUS) questionnaire: evaluation of measurement properties.

PURPOSE: This study was to conduct the psychometric validation of the patient and parent versions of the Hunter syndrome-functional outcomes for clinical understanding scale (HS-FOCUS). METHODS: Data collected in a 53-week placebo-controlled multinational trial were used to evaluate item performance and reliability, validity, and ability to detect change of the six HS-FOCUS function domains. RESULTS: HS-FOCUS was completed by 49 patients above 12 years old and 84 parents. Floor effects and high average inter-item correlations suggested that some items were less informative or redundant. For both patients and parents, the internal consistency and test-retest reliability met the >0.70 criteria for all domains except for the breathing, sleeping, and schooling/work in patients. Construct validity showed moderate to high correlations with CHAQ, CHQ, and HUI3 in activity-related concepts. Significant differences in domain scores were found in most domains among severity in disability measured by CHAQ DIS. Significant differences in HS-FOCUS change scores were found in patients whose CHAQ DIS score also changed. CONCLUSIONS: Psychometric validation of the HS-FOCUS demonstrates it is a reliable, valid, and responsive instrument that can be applied in clinical trials or disease registries. Findings on the individual item performance suggest some items could be removed without compromising its validity.

Bone marrow transplantation in children with Hunter syndrome: outcome after 7 to 17 years.

OBJECTIVE: To evaluate the effect of bone marrow transplantation in children with Hunter syndrome. STUDY DESIGN: Eight boys received a bone marrow graft between the ages of 3 and 16 years from 1990 to 2000. In 6 cases, the donor was a sibling with identical HLA status, in 1 case an unrelated donor with HLA-compatible, and in 1 case a mismatched unrelated donor. A complete multidisciplinary evaluation was performed yearly. RESULTS: Successful engraftment was achieved in all patients, with the proportion of donor cells reaching > or =95% 1 month after transplantation in all patients. Patients have been followed from between 7 and 17 years and all are still alive, except for 1 boy who died at the age of 10 from unrelated causes. Cardiovascular abnormalities stabilized in all patients, hepatosplenomegaly resolved, and joint stiffness improved, Perceptual hearing defects remained stable, and transmission hearing defects improved. Only 1 child required subsequent surgery to correct kyphosis. Neuropsychological outcome was variable and appeared to be related to the severity of the syndrome. CONCLUSIONS: Bone marrow transplantation is effective on the no neuropsychological symptoms of Hunter disease.

Psychological status of patients with mucopolysaccharidosis type II and their parents.

BACKGROUND: The aim of the present study was to delineate the psychological status of 10 patients with the attenuated phenotype of mucopolysaccharidosis type II (MPS-II) and their parents (six fathers and five mothers) for the improvement of clinical management. METHODS: Intellectual ability was evaluated using the Wechsler Intelligence Scale. Activities of daily living (ADL) was assessed using the Functional Independence Measure. The personality and psychiatric aspects were analyzed using the Yatabe-Guilford Personality test (Y-G test) and the Tree-Drawing Test. Mental health was assessed using the General Health Questionnaire 60 (GHQ-60) and State-Trait Anxiety Inventory (STAI). RESULTS: Intellectual background, measured with full-scale, verbal and performance IQ, were 72.8, 76.1 and 79.3, respectively. Nine of 10 patients were not judged as having neurosis and a psychotic tendency with the Y-G test. In the tree-drawing test, many patients drew a tree without ground, suggesting that they have difficulties in making relationships with surrounding people and the community. The child patient with a psychosis pattern on the Y-G test, drew a bizarre tree, suggesting psychological problems. GHQ-60 and STAI survey indicated that the patients and their parents had higher levels of anxiety. A significant negative correlation between GHQ-60 score and ADL (R = -0.77) was identified, suggesting that the psychological status may worsen as ADL decreases. CONCLUSIONS: Patients with MPS-II and their parents had higher risks for mental problems. Understanding psychological status is essential when providing genetic counseling or therapeutic intervention.

The management of children with Hunter syndrome - a case study.

Hunter syndrome (mucopolysaccharidosis type II) is a rare lysosomal storage disease caused by a deficiency of the lysosomal enzyme iduronate-2-sulphatase and the subsequent progressive cellular accumulation of glycosaminoglycans. Children with this debilitating disease can now be offered enzyme replacement therapy (ERT) with idursulfase to manage the signs and symptoms of the disease and to improve quality of life. As therapy involves a weekly infusion of enzyme, travel to the few designated specialist centres that provide treatment can be highly disruptive for both patients and carers. Providing ERT outside the hospital setting therefore offers a convenient alternative that can be delivered effectively with specialist nursing support. The authors report their experience of providing ERT to a patient with Hunter syndrome in a school. Through careful planning and the development of close working relationships between nurses, schools, local hospitals and patients' families, the authors found that managing patients outside the hospital setting can greatly benefit their quality of life.

Otologic manifestations of Hunter syndrome and their relationship with speech development.

The excessive storage of mucopolysaccharide in Hunter syndrome leads to various otologic manifestations. We interviewed 19 patients with Hunter syndrome to assess their otologic problems, and conducted audiologic tests and temporal bone CT. Patients with the intermediate or severe form exhibited severe speech delay by more than 2 years (12/14 patients). However, in patients with the mild form (5/5), speech development was not much disturbed (2/5), although otoscopic findings were similar. The hearing threshold determined by the auditory brainstem response differed significantly between the mild and intermediate/severe forms (p < 0.05). Therefore, patients with the mild form may benefit from active otologic intervention such as VT insertion, amplification, and speech therapy.

Fiberoptic intubation through an I-gel supraglottic airway in two patients with predicted difficult airway and intellectual disability.

We describe successful fiberoptic-guided tracheal intubation through the novel supraglottic "I-gel" airway in two uncooperative adult patients with genetic syndromes, learning disability, and predicted difficult airway, scheduled for complex dental treatment under general anesthesia. The I-gel maintained the airway immediately after induction, allowing oxygenation and ventilation. Location of the laryngeal inlet was successful on the first attempt with a fiberscope, and the tracheal tube was inserted into the trachea over the endoscope without complication in both patients. This report suggests another option for management of predicted difficult airways.

Evaluation of ADL in patients with Hunter disease using FIM score.

MPS type II (Hunter disease) results from deficiency of the lysosomal enzyme iduronate-2-sulfate sulfatase. Two forms of the disease have been recognized, based on absence or presence of progressive intellectual deterioration. This study aimed to assess activities of daily life (ADL) in 27 Hunter disease-affected Japanese patients, using a modified version of the functional independence measure (FIM). Scores of ADL for patients with a severe phenotype were significantly lower than those of control children. Total scores were highest around 5-7 years old, then progressively decreased, and scores <40 were obtained with patients aged 9 years or more. In contrast to motor scores, cognitive scores decreased rapidly, generally reaching a minimum score at around 7 years old. On the other hand, in children with attenuated phenotype, total scores increased progressively with age similar to control children. Two children who had the highest grades at elementary school showed maximum scores. However, all adult patients did not show maximum total scores, and 3 of 4 patients over 25 years old showed decreasing scores. Two children and two adults showed significant lower scores compared with other patients, suggesting an intermediate form from the view of ADL. This study elucidated the precise clinical state of Hunter disease with distinct numerical scores, in addition to previously described narrative data. To maintain the QOL of the patients better, they and their family need to know what specific difficulties they encounter, in which period they encounter them, and what support can fix them. Further ADL investigations with larger populations and/or long-term sequential examination could help the patients and family to understand them well.

A clinical study of 77 patients with mucopolysaccharidosis type II.

AIM: This study aims to assess the clinical features of 77 South American patients (73 Brazilian) with mucopolysaccharidosis type II (MPS II). METHODS: Details of the patients and their disease manifestations were obtained from a review of medical records, interviews with the patients and/or their families, and physical examination of the patients. RESULTS: Mean birth weight was 3360 g, median age at onset of symptoms was 18 months and median age at diagnosis was 6 years. For the whole sample (median age, 8.2 years; range, 2.8-53.0 years), neurological degeneration, typical pebbly skin lesions, seizures and extensive dermal melanocytosis were found in 23.3, 13.0, 13.0 and 1.3% of the cases, respectively. The most frequently reported echocardiogram abnormality was mitral valve regurgitation. Refraction errors were the most common ophthalmological manifestation. The following characteristics were found to be associated with the severe form of MPS II: earlier age at biochemical diagnosis, higher levels of urinary glycosaminoglycans, language development delay, behavioural disturbances, poor school performance and mental retardation. CONCLUSION: Our results suggest that there is a considerable delay between the onset of signs and symptoms and the diagnosis of MPS II in Brazil (and probably in South America as well), and that many complications of this disease are underdiagnosed and undertreated. Therefore, the implementation of programmes aiming to increase the awareness of the disease, the availability of biochemical diagnostic tests and the provision of better support to affected patients is urgently needed.

Prevention of Neurocognitive Deficiency in Mucopolysaccharidosis Type II Mice by Central Nervous System-Directed, AAV9-Mediated Iduronate Sulfatase Gene Transfer.

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is a rare X-linked recessive lysosomal disorder caused by defective iduronate-2-sulfatase (IDS), resulting in accumulation of heparan sulfate and dermatan sulfate glycosaminoglycans (GAGs). Enzyme replacement is the only Food and Drug Administration-approved therapy available for MPS II, but it is expensive and does not improve neurologic outcomes in MPS II patients. This study evaluated the effectiveness of adeno-associated virus (AAV) vector encoding human IDS delivered intracerebroventricularly in a murine model of MPS II. Supraphysiological levels of IDS were observed in the circulation (160-fold higher than wild type) for at least 28 weeks post injection and in most tested peripheral organs (up to 270-fold) at 10 months post injection. In contrast, only low levels of IDS were observed (7-40% of wild type) in all areas of the brain. Sustained IDS expression had a profound effect on normalization of GAG in all tested tissues and on prevention of hepatomegaly. Additionally, sustained IDS expression in the central nervous system (CNS) had a prominent effect in preventing neurocognitive deficit in MPS II mice treated at 2 months of age. This study demonstrates that CNS-directed, AAV9 mediated gene transfer is a potentially effective treatment for Hunter syndrome, as well as other monogenic disorders with neurologic involvement.

Barriers to home care and social support for an adolescent with disability.

Home care for children with disability has expanded in the last twenty years in order to support the child and family at home and avoid hospitalization or long term care facilities. A case story is presented to show several barriers to home care for a 15 year old boy with Hunter's syndrome and severe disability. The case showed a need for further education and coordination of professionals in order for pediatric home care to be more efficient and supportive in Israel.

[Severe complications following an adeno-tonsillectomy in a patient with Hunter's syndrome (MPS II)]. / Ernstige complicaties na een ate bij een patiënt met de ziekte van Hunter (MPS II).

The history of an 11-year old boy with Hunter-syndrome is presented who developed respiratory and haemostatic complications following adenoidectomy and tonsillectomy because of grossly enlarged and chronically infected adenoid and tonsils and recurrent upper respiratory infections.