Intracerebroventricular enzyme replacement therapy in patients with neuronopathic mucopolysaccharidosis type II: Final report of 5-year results from a Japanese open-label phase 1/2 study.

Intravenous idursulfase is standard treatment for mucopolysaccharidosis II (MPS II) in Japan. In the interim analysis of this open-label, phase 1/2 study (Center for Clinical Trials, Japan Medical Association: JMA-IIA00350), intracerebroventricular (ICV) idursulfase beta was well tolerated, suppressed cerebrospinal fluid (CSF) heparan sulfate (HS) levels, and stabilized developmental decline over 100 weeks in Japanese children with MPS II. Here, we report the final study results, representing 5 years of ICV idursulfase beta treatment. Six male patients with MPS II and developmental delay were enrolled starting in June 2016 and followed until March 2021. Patients received up to 30 mg ICV idursulfase beta every 4 weeks. Outcomes included CSF HS levels, developmental age (DA) (assessed by the Kyoto Scale of Psychological Development), and safety (adverse events). Monitoring by laboratory biochemistry tests, urinary uronic tests, immunogenicity tests, and head computed tomography or magnetic resonance imaging were also conducted regularly. Following ICV idursulfase beta administration, mean CSF HS concentrations decreased from 7.75 µg/mL at baseline to 2.15 µg/mL at final injection (72.3% reduction). Mean DA increased from 23.2 months at screening to 36.0 months at final observation. In five patients with null mutations, mean DA at the final observation was higher than or did not regress compared with that of historical controls receiving intravenous idursulfase only, and the change in DA was greater in patients who started administration aged ≤3 years than in those aged >3 years (+28.7 vs -6.5 months). The difference in DA change versus historical controls in individual patients was +39.5, +40.8, +17.8, +10.5, +7.6 and - 4.5 (mean + 18.6). Common ICV idursulfase beta-related adverse events were vomiting, pyrexia, gastroenteritis, and upper respiratory tract infection (most mild/moderate). These results suggest that long-term ICV idursulfase beta treatment improved neurological symptoms in Japanese children with neuronopathic MPS II.

Potential patient screening for late-onset Pompe disease in suspected sleep apnea: a rationale and study design for a Prospective Multicenter Observational Cohort Study in Japan (PSSAP-J Study).

BACKGROUND: Pompe disease is an autosomal recessive disorder caused by deficiency of the acid α-glucosidase (GAA) enzyme. GAA deficiency induces progressive glycogen accumulation which leads to weakness of the respiratory muscle including the diaphragm. Pompe disease is one of the few myopathies, for which an established therapy is available. Thus, earlier detection of potential late-onset Pompe disease (LOPD) and earlier intervention would have a significant clinical impact. PURPOSE: Our hypothesis is that sleep problems including sleep disordered breathing (SDB) and clinical symptoms may indicate an early stage of LOPD since decreased respiratory muscle activity generally first presents during sleep. Thus, the aims of this prospective, multicenter observational cohort study in Japan (PSSAP-J) are to demonstrate a higher prevalence of LOPD in a sleep lab-based population (primary outcome), and to identify predictive factors for LOPD from findings in diagnostic polysomnography (PSG) and clinical symptoms (secondary outcomes). METHODS: The study design is a prospective multicenter observational cohort study. Consecutive patients who present to sleep labs due to suspected SDB for an overnight PSG will be enrolled. All patients will be measured for creatine kinase, GAA activity, and if necessary, genetic analysis of GAA. Furthermore, chest X-ray, pulmonary function test, and arterial blood gas analysis will be collected. Then, prevalence and specific findings of LOPD will be assessed. RESULT: Congenital myopathy shows a shift from slow-deep to rapid-shallow breathing during transition from wakefulness to sleep accompanying a symptom of waking with gasping (actual further results are pending). DISCUSSION: The distribution in respiratory physiology between during wakefulness and sleep specific to LOPD may provide insights into early-stage detection. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000039191, UMIN Clinical Trials Registry ( http://www.umin.ac.jp/ctr ).

Association between the clinical presentation of congenital anomalies of the kidney and urinary tract (CAKUT) and gene mutations: an analysis of 66 patients at a single institution.

BACKGROUND: The association between the clinical presentation of congenital anomalies of the kidney and urinary tract (CAKUT) and gene mutations has yet to be fully explored. METHODS: In this retrospective cohort study, we examined patients with CAKUT who underwent gene analysis. The analysis was performed in patients with bilateral renal lesions, extrarenal complications, or a family history of renal disease. The data from the diagnosis, gene mutations, and other complications were analyzed. RESULTS: In total, 66 patients with CAKUT were included. Of these, gene mutations were detected in 14 patients. Bilateral renal lesions were significantly related to the identification of gene mutations (p = 0.02), and no gene mutations were observed in patients with lower urinary tract obstruction (six patients). There was no significant difference in the rate of gene mutations between those with or without extrarenal complications (p = 0.76). The HNF1ß gene mutation was identified in most of the patients with hypodysplastic kidney with multicystic dysplastic kidney (six of seven patients). There was no significant difference in the presence or absence of gene mutations with respect to the renal survival rate (log-rank test p = 0.53). The renal prognosis varied, but the differences were not statistically significant for any of the gene mutations. CONCLUSIONS: CAKUT with bilateral renal lesions were significantly related to gene mutations. We recommend that CAKUT-related gene analysis be considered in cases of bilateral renal lesions. No gene mutations were observed in patients with lower urinary tract obstruction. The renal prognosis varied for each gene mutation.

Liver transplantation: New treatment for mucopolysaccharidosis type VI in rats.

BACKGROUND: Mucopolysaccharidosis (MPS) VI is a rare, autosomal recessive congenital metabolic disorder caused by deficient activity of the lysosomal metabolic enzyme, N-acetylgalactosamine 4-sulfatase. Enzyme replacement therapy (ERT) is the current treatment for MPS VI, although it involves limited compliance to the therapy and high cost. The aim of this study was to develop a new method of treatment by conducting an orthotopic liver transplantation (LTx) using an animal model of human MPS VI, and to evaluate and examine its effectiveness for treating MPS VI. METHODS: LTx was carried out from normal unaffected to affected MPS VI rats (MPR), which were then killed after LTx, and tissues from the heart, spleen, and knee joint, as well as serum, collected for biological and morphologic evaluation. RESULTS: Liver-transplanted (LTx) MPR had the same level of N-acetylgalactosamine 4-sulfatase activity in the liver and lungs as normal unaffected MPR, and the urinary secretion of mucopolysaccharides/glycosaminoglycan (GAG) in LTx MPR was significantly decreased. Furthermore, on histopathology, the spleens of LTx MPR showed elimination of vacuole cells. In the knee joints, growth plates became thinner, and on radiography the facial and cranial bones of LTx MPR were morphologically normal. CONCLUSIONS: LTx from normal to affected MPR was effective for symptoms of MPS and accumulation of GAG, suggesting that LTx could be a promising alternative approach for MPS VI.

The efficacy of intracerebroventricular idursulfase-beta enzyme replacement therapy in mucopolysaccharidosis II murine model: heparan sulfate in cerebrospinal fluid as a clinical biomarker of neuropathology.

Mucopolysaccharidosis II (MPS II) is caused by a deficiency of iduronate-2-sulfatase that results in accumulation of glycosaminoglycans (GAG), including heparan sulfate (HS), which is considered to contribute to neuropathology. We examined the efficacy of intracerebroventricular (ICV) enzyme replacement therapy (ERT) of idursulfase-beta (IDS-ß) and evaluated the usefulness of HS as a biomarker for neuropathology in MPS II mice. We first examined the efficacy of three different doses (3, 10, and 30 µg) of single ICV injections of IDS-ß in MPS II mice. After the single-injection study, its long-term efficacy was elucidated with 30 µg of IDS-ß ICV injections repeated every 4 weeks for 24 weeks. The efficacy was assessed by the HS content in the cerebrospinal fluid (CSF) and the brain of the animals along with histologic examinations and behavioral tests. In the single-injection study, the 30 µg of IDS-ß ICV injection showed significant reductions of HS content in brain and CSF that were maintained for 28 days. Furthermore, HS content in CSF was significantly correlated with HS content in brain. In the long-term repeated-injection study, the HS content in the brain and CSF was also significantly reduced and correlated. The histologic examinations showed a reduction in lysosomal storage. A significant improvement in memory/learning function was observed in open-field and fear-conditioning tests. ICV ERT with 30 µg of IDS-ß produced significant improvements in biochemical, histological, and functional parameters in MPS II mice. Furthermore, we demonstrate for the first time that the HS in the CSF had significant positive correlation with brain tissue HS and GAG levels, suggesting HS in CSF as a useful clinical biomarker for neuropathology.

Cerebral magnetic resonance findings during enzyme replacement therapy in mucopolysaccharidosis.

BACKGROUND: Although enzyme replacement therapy (ERT) is an effective treatment for mucopolysaccharidosis (MPS) types I, II, IVA and VI, its effectiveness in children with central nervous system (CNS) disorders is said to be poor because the blood-brain barrier cannot be penetrated by ERT drugs. OBJECTIVE: To assess CNS involvement in mucopolysaccharidosis at the start of enzyme replacement therapy and to investigate the time course of ERT in the central nervous system. MATERIALS AND METHODS: We performed brain MRI in 17 children and young adults who underwent ERT. The clinical severity was classified as attenuated or severe by a specialist pediatrician, based on the clinical symptoms and genotypes. At the start of ERT, we scored nine parameters using two- or three-point scales based on the severity of the disease revealed on MRI scans. After the start of ERT, we compared the initial and follow-up MRI scans, and classified the findings as no change, improved or worse. We then compared the results with the changes in clinical findings. RESULTS: At the start of ERT, comparison of the clinical symptoms and image scores revealed differences between severe and attenuated mucopolysaccharidosis. The scores in patients with severe MPS ranged from 9 to 16 (mean 12.2); for patients with attenuated MPS, they ranged from 2 to 11 (mean 6.4). Images of the four patients with severe MPS showed ventricular dilation and brain atrophy. Such findings were made in only 2 of 13 patients with attenuated MPS. The results after the start of ERT showed that 11/17 (65%) patients manifested improvement or no change. All five patients with MPS I experienced improvement in some regions. There were no new lesions. One patient with MPS II experienced worsening of his CNS symptoms, and his MRI findings revealed more severe ventricular dilation, brain atrophy and white matter lesions. CONCLUSION: Ventricular dilation and brain atrophy on imaging studies might represent useful markers in predicting the severity of mucopolysaccharidosis and worsening of CNS symptoms. Enzyme replacement therapy improves CNS images in MPS I and has an inhibitory effect on the occurrence of new lesions in MPS II.

Molecular diagnosis of 65 families with mucopolysaccharidosis type II (Hunter syndrome) characterized by 16 novel mutations in the IDS gene: Genetic, pathological, and structural studies on iduronate-2-sulfatase.

Mucopolysaccharidosis type II (MPS II: also called as Hunter syndrome) is an X-linked recessive lysosomal storage disorder characterized by the accumulation of extracellular glycosaminoglycans due to the deficiency of the enzyme iduronate-2-sulfatase (IDS). Previous observations suggested that MPS II can be classified into two distinct disease subtypes: (1) severe type of MPS II involves a decline in the cognitive ability of a patient and (2) attenuated type of MPS II exhibits no such intellectual phenotype. To determine whether such disease subtypes of MPS II could be explained by genetic diagnosis, we analyzed mutations in the IDS gene of 65 patients suffering from MPS II among the Japanese population who were diagnosed with both the accumulation of urinary glycosaminoglycans and a decrease in their IDS enzyme activity between 2004 and 2014. Among the specimens examined, we identified the following mutations: 33 missense, 8 nonsense, 7 frameshift, 4 intronic changes affecting splicing, 8 recombinations involving IDS-IDS2, and 7 other mutations including 4 large deletions. Consistent with the previous data, the results of our study showed that most of the attenuated phenotype was derived from the missense mutations of the IDS gene, whereas mutations associated with a large structural alteration including recombination, splicing, frameshift, and nonsense mutations were linked to the severe phenotype of MPS II. Furthermore, we conducted a homology modeling study of IDS P120R and N534I mutant as representatives of the causative mutation of the severe and attenuated type of MPS II, respectively. We found that the substitution of P120R of the IDS enzyme was predicted to deform the α-helix generated by I119-F123, leading to the major structural alteration of the wild-type IDS enzyme. In sharp contrast, the effect of the structural alteration of N534I was marginal; thus, this mutation was pathogenically predicted to be associated with the attenuated type of MPS II. These results suggest that a combination of the genomic diagnosis of the IDS gene and the structural prediction of the IDS enzyme could enable the prediction of a phenotype more effectively.

Identifying the need for a multidisciplinary approach for early recognition of mucopolysaccharidosis VI (MPS VI).

Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is caused by deficient activity of the enzyme, N-acetylgalactosamine-4-sulfatase, resulting in impaired degradation of the glycosaminoglycan dermatan sulfate. Patients experience a range of manifestations including joint contractures, short stature, dysostosis multiplex, coarse facial features, decreased pulmonary function, cardiac abnormalities, corneal clouding and shortened life span. Recently, clinicians from institutions in the Asia-Pacific region met to discuss the occurrence and implications of delayed diagnosis and misdiagnosis of MPS VI in the patients they have managed. Eighteen patients (44% female) were diagnosed. The most common sign presented by the patients was bone deformities in 11 patients (65%). Delays to diagnosis occurred due to the lack of or distance to diagnostic facilities for four patients (31%), alternative diagnoses for two patients (15%), and misleading symptoms experienced by two patients (15%). Several patients experienced manifestations that were subtler than would be expected and were subsequently overlooked. Several cases highlighted the unique challenges associated with diagnosing MPS VI from the perspective of different specialties and provide insights into how these patients initially present, which may help to elucidate strategies to improve the diagnosis of MPS VI.

CT and endoscopic evaluation of larynx and trachea in mucopolysaccharidoses.

BACKGROUND: Mucopolysaccharidoses (MPSs) are lysosomal storage disorders caused by lysosomal enzyme deficiencies that result in systemic accumulation of glycosaminoglycans (GAGs). Accumulation of GAGs in the upper airway can lead to respiratory failure. The aim of this study was to investigate changes of the airway by flexible endoscopy and CT. METHODS: Thirty-five patients aging from 2 to 16 years (mean: 9.2±4.4 years) participated in this study. The majority had MPS I (n=5) or MPS II (n=25). The shape of the trachea and the cross-sectional trachea surface area (TSA) was determined at the Th1 and Th2 levels. Airway obstruction was evaluated from endoscopic findings and classified into 3 grades (Grades 0, 1, and 2). Forty-five patients in the control group who underwent tracheal CT for other conditions were retrospectively selected from the database. RESULTS: Tracheal morphology was abnormal in 50-60%, which showed a transversely collapsing narrow trachea. Tracheal deformity was severe in MPS II and MPS IV. The mean TSA of the MPS patients was 55.5±29.0 mm(2) at Th1 and 61.4±29.0 mm(2) at Th2, while that of the control group was 90.1±41.9 mm(2) and 87.9±39.3 mm(2), respectively. Respiratory distress was noted in 15 of the 35 patients, among whom 7 patients showed tracheal deformity and 7 patients had laryngeal redundancy. Three patients had no abnormalities of the larynx or trachea, so other factors such as pharyngeal stenosis or lower airway stenosis might have contributed to their respiratory distress. CONCLUSION: CT and flexible endoscopy allow quantitative and morphological evaluation of airway narrowing, which is beneficial for airway management in MPS children.

Long-term efficacy of intrathecal cyclodextrin in patients with Niemann-Pick disease type C.

BACKGROUND AND OBJECTIVES: Niemann-Pick type C (NPC) is a rare lysosomal storage disease characterized by hepatosplenomegaly and progressive neurological deterioration due to abnormal intracellular cholesterol transport. Cyclic oligosaccharide 2-hydroxypropyl-ß-cyclodextrin (HPBCD) is an effective treatment for NPC; however, few reports have shown its long-term efficacy and safety. To demonstrate long-term efficacy and safety of intrathecal HPBCD (IT-HPBCD) treatment for NPC, we herein reports five patients with NPC treated using IT-HPBCD for 4-11 years. CASES AND RESULTS: Patients' ages at the onset ranged from 1.5 to 20 years. Notably, all patients showed rapid disease progression despite treatment with miglustat before IT-HPBCD treatment. Similarly, some patients showed transient improvement; however, all patients' conditions stabilized after long-term IT-HPBCD therapy. Mild-to-moderate hearing loss was observed in three patients. Furthermore, long-term treatment with IT-HPBCD may suppress neurological deterioration in patients with NPC; however, patients still experience some disease progression. CONCLUSIONS: Long-term treatment with IT-HPBCD may suppress neurological deterioration in patients with NPC; however, the treatment outcome is dependent on the neurological status at the time of diagnosis, and disease progression is not completely inhibited. Awareness of the disease and newborn screening is needed for earlier disease detection. In addition, further optimization of the treatment protocol and additional treatments are needed to improve patient outcomes.

Effects of idursulfase enzyme replacement therapy for Mucopolysaccharidosis type II when started in early infancy: comparison in two siblings.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder that is progressive and involves multiple organs and tissues. While enzyme replacement therapy (ERT) with idursulfase has been shown to improve many somatic features of the disease, some such as dysostosis multiplex and cardiac valve disease appear irreversible once established, and little is known about the preventative effects of ERT in pre-symptomatic patients. We report on two siblings with severe MPS II caused by an inversion mutation with recombination breakpoints located within the IDS gene and its adjacent pseudogene, IDS-2. The siblings initiated treatment with idursulfase at 3.0 years (older brother) and 4 months (younger brother) of age, and we compared their outcomes following 2 years of treatment. At the start of treatment, the older brother showed typical features of MPS II, including intellectual disability. After 34 months of ERT, his somatic disease was stable or improved, but he continued to decline cognitively. By comparison, after 32 months of ERT his younger brother remained free from most of the somatic features that had already appeared in his brother at the same age, manifesting only exudative otitis media. Skeletal X-rays revealed characteristic signs of dysostosis multiplex in the older brother at the initiation of treatment that were unchanged two years later, whereas the younger brother showed only slight findings of dysostosis multiplex throughout the treatment period. The younger brother's developmental quotient trended downward over time to just below the normal range. These findings suggest that pre-symptomatic initiation of ERT may prevent or attenuate progression of the somatic features of MPS II. Follow-up in a larger number of patients is required to confirm the additive long-term benefits of ERT in pre-symptomatic patients.

A Neonate with Mucopolysaccharidosis Type VII with Intractable Ascites.

We report a case of a patient with severe fetal hydrops and refractory ascites, diagnosed as mucopolysaccharidosis type VII (MPS VII) by whole-exome sequencing, and discharged at 5 months of age after long-term ventilatory management. A male neonate was born by emergency cesarean section due to fetal distress at 30 1/7 weeks' gestation. Physical examination and X-rays revealed pleural effusion, ascites, and generalized edema, indicating severe fetal hydrops. He underwent tracheal intubation because of respiratory distress that was attributed to massive ascites, pulmonary hypoplasia, and pulmonary hypertension. He received mechanical ventilation and inhaled nitric oxide therapy. Prednisone, octreotide, and a factor XIII preparation were used as the treatment for ascites, and the ascites gradually decreased. He was extubated within 2 months of age. At 4 months of age, the results of whole-exome sequencing of the cord blood showed a compound heterozygous mutation in the GUSB gene, the gene responsible for MPS VII. Enzyme replacement therapy was initiated, and the ascites was resolved. Careful systemic management, including lung-protective respiratory management and the early establishment of nutrition, is important for the long-term survival of infants with fetal hydrops, and early aggressive workup, including whole-genome sequencing for the cause, should be performed in the case of refractory ascites.

A pediatric case of congenital stromal corneal dystrophy caused by the novel variant c.953del of the DCN gene.

We report a 1-year-old girl with congenital stromal corneal dystrophy confirmed by genetic analysis. The ocular phenotype included diffuse opacity over the corneal stroma bilaterally. We performed a genetic analysis to provide counseling to the parents regarding the recurrence rate. Whole exome sequencing was performed on her and her parents, and a novel de novo variant, NM_001920.5: c.953del, p.(Asn318Thrfs*10), in the DCN gene was identified in the patient.

Current diagnosis and management of mucopolysaccharidosis VI in the Asia-Pacific region.

INTRODUCTION: Mucopolysaccharidosis (MPS) type VI (Maroteaux-Lamy syndrome) is a clinically heterogeneous lysosomal storage disorder. It presents significant diagnostic and treatment challenges due to the rarity of the disease and complexity of the phenotype. As information about MPS VI in Asia-Pacific countries is limited, a survey was conducted to assess current practices for diagnosis and management of MPS VI in this region. The participants were selected based on their experience in diagnosing and managing MPS patients. METHODS: The survey comprised 29 structured quantitative or qualitative questions. Follow-up consultations were undertaken to discuss the data further. RESULTS: Thirteen physicians from eight countries or regions (Australia, China, Hong Kong, Japan, Malaysia, Philippines, Taiwan and Thailand) were surveyed. At the time of the survey twenty-two patients with MPS VI were directly treated by the respondents and most (~80%) had rapidly progressing disease. A wide range of medical specialists are involved in managing patients with MPS VI, the most common being orthopedic surgeons, pediatricians and geneticists. The availability/accessibility of diagnostic tools, therapies and national insurance coverage vary greatly across the countries/regions and, in some cases, between different regions within the same country. Currently, there are national MPS management groups in Australia and Japan. Australia, Taiwan and Hong Kong have local guidelines for managing MPS and local MPS registries are available in Australia, Taiwan, and Japan. CONCLUSIONS: This survey highlights differences in the diagnosis and management of MPS VI between Asia-Pacific countries/regions. Important barriers to advancing the identification, understanding and treatment of MPS VI include the paucity of epidemiological information, limited access to laboratory diagnostics and therapies, low disease awareness, and a lack of monitoring and treatment guidelines. There is a clear need to facilitate communications between physicians and establish regional or national disease registries, a multidisciplinary referral network, and a centralized diagnostic and management framework.

Maternal uniparental disomy of chromosome 7 underlying argininosuccinic aciduria and Silver-Russell syndrome.

We describe a patient presenting with argininosuccinic aciduria and Silver-Russell syndrome (SRS). SRS was caused by maternal uniparental disomy of chromosome 7 (UPD(7)mat). UPD(7)mat also unmasked a maternally inherited splicing variant in ASL on chromosome 7, leading to the onset of argininosuccinic aciduria. The phenotype of the present case was more severe than that of a previous case, demonstrating a phenotypic variation in the combination of argininosuccinic aciduria and SRS.

Automated urinary sediment detection for Fabry disease using deep-learning algorithms.

Fabry disease is a congenital lysosomal storage disease, and most of these cases develop organ damage in middle age. There are some promising therapeutic options for this disorder, which can stabilize the progression of the disease. However, a long delay in diagnosis prevents early intervention, resulting in treatment failure. Because Fabry disease is a rare disease, it is not well recognized and disease specific screening tests are rarely performed. Hence, a novel approach to for detecting patients with a widely practiced clinical test is crucial for the early detection of the disease. Recently, decision support systems based on artificial intelligence (AI) have been developed in many clinical fields. However, the construction of these models requires datasets from a large number of samples; this aspect is one of the main obstacles in AI-based approaches for rare diseases. In this study, with a novel image amplification method to construct the dataset for AI-model training, we built the deep neural-network model to detect Fabry cases from their urine samples. Sensitivity, specificity, and the AUC of the models on validation dataset were 0.902 (95% CI, 0.900-0.903), 0.977 (0.950-0.980), and 0.968 (0.964-0.972), respectively. This model could also extract disease-specific findings that are interpretable with human recognition. These results indicate that we can apply novel AI models for rare diseases based on this image amplification method we developed. We expect this approach could contribute to the diagnosis of Fabry disease. Synopsis: This is the first reported AI-based decision support system to detect undiagnosed Fabry cases, and our new image amplification method will contribute to the AI models for other rare disorders.

Enzyme replacement therapy attenuates disease progression in two Japanese siblings with mucopolysaccharidosis type VI.

Mucopolysaccharidosis type VI (MPS VI) is a progressive, multisystem autosomal recessive lysosomal disorder resulting from deficient N-acetylgalactosamine-4-sulphatase (ASB) and the consequent accumulation of glycosaminoglycan (GAG). Preclinical and clinical studies had demonstrated clinical benefits of early initiation of systemic therapies in patients with MPS. In this case report, two siblings with MPS VI started enzyme replacement therapy (ERT) with weekly infusions of recombinant human ASB (Galsulfase) at 1mg/kg. Sibling 1 started ERT 5.6 years of age and Sibling 2 was 6 weeks old. The disease status in these two siblings prior to and for no less than 36 months of ERT was followed up and compared. The treatment was well tolerated by both siblings. During 36 months of ERT, symptoms typical of MPS VI including short stature, progressive dysmorphic facial features, hepatosplenomegaly, hearing impairment, corneal clouding, and dysostosis multiplex were largely absent in the younger sibling. Her cardiac functions and joint mobility were well preserved. On the other hand, her affected brother had typical MPS VI phenotypic features described above before commencing ERT at the equivalent age, of 3 years. There was significant improvement in the shoulder range of motion and hearing loss after 36 months of treatment and cardiac function was largely preserved. His skeletal deformity and short stature remained unchanged. The results showed that early ERT initiated at newborn is safe and effective in preventing or slowing down disease progression of MPS VI including bone deformities. These observations indicate that early diagnosis and treatment of MPS VI before development of an irreversible disease is critical for optimal clinical outcome.

Newborn screening for Pompe disease in Japan.

Pompe disease is caused by a deficiency of acid alpha-glucosidase (GAA) that results in glycogen accumulation, primarily in muscle. Newborn screening (NBS) for Pompe disease has been initiated in Taiwan and is reportedly successful. However, the comparatively high frequency of pseudodeficiency allele makes NBS for Pompe disease complicated in Taiwan. To investigate the feasibility of NBS for Pompe disease in Japan, we obtained dried blood spots (DBSs) from 496 healthy Japanese controls, 29 Japanese patients with Pompe disease, and five obligate carriers, and assayed GAA activity under the following conditions: (1) total GAA measured at pH 3.8, (2) GAA measured at pH 3.8 in the presence of acarbose, and (3) neutral glucosidase activity (NAG) measured at pH 7.0 without acarbose. The % inhibition and NAG/GAA ratio were calculated. For screening, samples with GAA<8% of the normal mean, % inhibition>60%, and NAG/GAA ratio>30 were considered to be positive. Two false positive cases (0.3%) were found, one was a healthy homozygote of pseudodeficiency allele (c.1726G>A). The low false-positive rate suggests that NBS for Pompe disease is feasible in Japan.

Glycerol homeostasis and metabolism in glycerol kinase carrier mice.

To examine glycerol homeostasis and metabolism is essential for understanding of pathogenesis and evaluation of treatment efficacy in disorders of glycerol metabolism. In this study, we designed the intraperitoneal glycerol tolerance test (IPGlyTT) and studied glycerol tolerance in vivo using glycerol kinase (Gyk) carrier (C) and wild type (WT) mice. Serum glycerol concentrations in WT almost normalized at 90 min after injection, whereas Gyk C mice retained high serum glycerol concentrations at least until 180 min after injection. These results showed that glycerol tolerance was impaired in Gyk C mice compared to WT mice. The IPGlyTT is useful in accessing glycerol homeostasis and metabolism in animal models such as Gyk C mice and will be valuable in assessing therapeutic interventions in Gyk KO mice.

Impact of intracerebroventricular enzyme replacement therapy in patients with neuronopathic mucopolysaccharidosis type II.

This open-label, phase 1/2 study (JMACCT CTR JMA-IIA00350) evaluated the efficacy and safety of intracerebroventricular idursulfase beta in patients with mucopolysaccharidosis II (MPS II). Herein, we report the 100-week results. Six patients with severe MPS II aged 23-65 months were enrolled. Idursulfase beta (increasing from 1 to 30 mg between weeks 0 and 24, followed by a 30-mg final dose) was administered intracerebroventricularly once every 4 weeks using an implanted cerebrospinal fluid (CSF) reservoir; intravenous administration of idursulfase was also continued throughout the study. Efficacy endpoints included developmental age by the Kyoto Scale of Psychological Development 2001 and heparan sulfate (HS) concentration in CSF (primary outcome). In all six patients, HS concentrations decreased (40%-80%) from baseline to week 100. For overall developmental age, the difference in change from baseline to week 100 in each patient compared with patients treated by intravenous idursulfase administration (n = 13) was +8.0, +14.5, +4.5, +3.7, +8.2, and -8.3 months (mean, +5.1 months). Idursulfase beta was well tolerated. The most common adverse events were pyrexia, upper respiratory tract infection, and vomiting. The results suggest that intracerebroventricular idursulfase beta is well tolerated and can be effective at preventing and stabilizing developmental decline in patients with neuronopathic MPS II.