D-mannose as a new therapy for fucokinase deficiency-related congenital disorder of glycosylation (FCSK-CDG).

INTRODUCTION: Fucokinase deficiency-related congenital disorder of glycosylation (FCSK-CDG) is a rare autosomal recessive inborn error of metabolism characterized by a decreased flux through the salvage pathway of GDP-fucose biosynthesis due to a block in the recycling of L-fucose that exits the lysosome. FCSK-CDG has been described in 5 individuals to date in the medical literature, with a phenotype comprising global developmental delays/intellectual disability, hypotonia, abnormal myelination, posterior ocular disease, growth and feeding failure, immune deficiency, and chronic diarrhea, without clear therapeutic recommendations. PATIENT AND METHODS: In a so far unreported FCSK-CDG patient, we studied proteomics and glycoproteomics in vitro in patient-derived fibroblasts and also performed in vivo glycomics, before and after treatment with either D-Mannose or L-Fucose. RESULTS: We observed a marked increase in fucosylation after D-mannose supplementation in fibroblasts compared to treatment with L-Fucose. The patient was then treated with D-mannose at 850 mg/kg/d, with resolution of the chronic diarrhea, resolution of oral aversion, improved weight gain, and observed developmental gains. Serum N-glycan profiles showed an improvement in the abundance of fucosylated glycans after treatment. No treatment-attributed adverse effects were observed. CONCLUSION: D-mannose is a promising new treatment for FCSK-CDG.

Impaired mitophagy in Sanfilippo a mice causes hypertriglyceridemia and brown adipose tissue activation.

Lysosomal storage diseases result in various developmental and physiological complications, including cachexia. To study the causes for the negative energy balance associated with cachexia, we assessed the impact of sulfamidase deficiency and heparan sulfate storage on energy homeostasis and metabolism in a mouse model of type IIIa mucopolysaccharidosis (MPS IIIa, Sanfilippo A syndrome). At 12-weeks of age, MPS IIIa mice exhibited fasting and postprandial hypertriglyceridemia compared with wildtype mice, with a reduction of white and brown adipose tissues. Partitioning of dietary [3H]triolein showed a marked increase in intestinal uptake and secretion, whereas hepatic production and clearance of triglyceride-rich lipoproteins did not differ from wildtype controls. Uptake of dietary triolein was also elevated in brown adipose tissue (BAT), and notable increases in beige adipose tissue occurred, resulting in hyperthermia, hyperphagia, hyperdipsia, and increased energy expenditure. Furthermore, fasted MPS IIIa mice remained hyperthermic when subjected to low temperature but became cachexic and profoundly hypothermic when treated with a lipolytic inhibitor. We demonstrated that the reliance on increased lipid fueling of BAT was driven by a reduced ability to generate energy from stored lipids within the depot. These alterations arose from impaired autophagosome-lysosome fusion, resulting in increased mitochondria content in beige and BAT. Finally, we show that increased mitochondria content in BAT and postprandial dyslipidemia was partially reversed upon 5-week treatment with recombinant sulfamidase. We hypothesize that increased BAT activity and persistent increases in energy demand in MPS IIIa mice contribute to the negative energy balance observed in patients with MPS IIIa.

C-Type Natriuretic Peptide Analogue Therapy in Children with Achondroplasia.

BACKGROUND: Achondroplasia is a genetic disorder that inhibits endochondral ossification, resulting in disproportionate short stature and clinically significant medical complications. Vosoritide is a biologic analogue of C-type natriuretic peptide, a potent stimulator of endochondral ossification. METHODS: In a multinational, phase 2, dose-finding study and extension study, we evaluated the safety and side-effect profile of vosoritide in children (5 to 14 years of age) with achondroplasia. A total of 35 children were enrolled in four sequential cohorts to receive vosoritide at a once-daily subcutaneous dose of 2.5 µg per kilogram of body weight (8 patients in cohort 1), 7.5 µg per kilogram (8 patients in cohort 2), 15.0 µg per kilogram (10 patients in cohort 3), or 30.0 µg per kilogram (9 patients in cohort 4). After 6 months, the dose in cohort 1 was increased to 7.5 µg per kilogram and then to 15.0 µg per kilogram, and in cohort 2, the dose was increased to 15.0 µg per kilogram; the patients in cohorts 3 and 4 continued to receive their initial doses. At the time of data cutoff, the 24-month dose-finding study had been completed, and 30 patients had been enrolled in an ongoing long-term extension study; the median duration of follow-up across both studies was 42 months. RESULTS: During the treatment periods in the dose-finding and extension studies, adverse events occurred in 35 of 35 patients (100%), and serious adverse events occurred in 4 of 35 patients (11%). Therapy was discontinued in 6 patients (in 1 because of an adverse event). During the first 6 months of treatment, a dose-dependent increase in the annualized growth velocity was observed with vosoritide up to a dose of 15.0 µg per kilogram, and a sustained increase in the annualized growth velocity was observed at doses of 15.0 and 30.0 µg per kilogram for up to 42 months. CONCLUSIONS: In children with achondroplasia, once-daily subcutaneous administration of vosoritide was associated with a side-effect profile that appeared generally mild. Treatment resulted in a sustained increase in the annualized growth velocity for up to 42 months. (Funded by BioMarin Pharmaceutical; ClinicalTrials.gov numbers, NCT01603095, NCT02055157, and NCT02724228.).

Evaluation of artificial signal peptides for secretion of two lysosomal enzymes in CHO cells.

Enzyme replacement therapy (ERT) is a scientifically rational and clinically proven treatment for lysosomal storage diseases. Most enzymes used for ERT are purified from the culture supernatant of mammalian cells. However, it is challenging to purify lysosomal enzymes with sufficient quality and quantity for clinical use due to their low secretion levels in mammalian cell systems. To improve the secretion efficiency of recombinant lysosomal enzymes, we evaluated the impact of artificial signal peptides on the production of recombinant lysosomal enzymes in Chinese hamster ovary (CHO) cell lines. We engineered two recombinant human lysosomal enzymes, N-acetyl-α-glucosaminidase (rhNAGLU) and glucosamine (N-acetyl)-6-sulfatase (rhGNS), by replacing their native signal peptides with nine different signal peptides derived from highly secretory proteins and expressed them in CHO K1 cells. When comparing the native signal peptides, we found that rhGNS was secreted into media at higher levels than rhNAGLU. The secretion of rhNAGLU and rhGNS can, however, be carefully controlled by altering signal peptides. The secretion of rhNAGLU was relatively higher with murine Igκ light chain and human chymotrypsinogen B1 signal peptides, whereas Igκ light chain signal peptide 1 and human chymotrypsinogen B1 signal peptides were more effective for rhGNS secretion, suggesting that human chymotrypsinogen B1 signal peptide is the most appropriate for increasing lysosomal enzyme secretion. Collectively, our results indicate that altering signal peptide can modulate the secretion of recombinant lysosome enzymes and will enable lysosomal enzyme production for clinical use.

IRF2BPL Is Associated with Neurological Phenotypes.

Interferon regulatory factor 2 binding protein-like (IRF2BPL) encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals who carry damaging heterozygous variants in IRF2BPL and are affected with neurological symptoms. Five individuals who carry IRF2BPL nonsense variants resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The IRF2BPL bioinformatics signature based on population genomics is consistent with a gene that is intolerant to variation. We show that the fruit-fly IRF2BPL ortholog, called pits (protein interacting with Ttk69 and Sin3A), is broadly detected, including in the nervous system. Complete loss of pits is lethal early in development, whereas partial knockdown with RNA interference in neurons leads to neurodegeneration, revealing a requirement for this gene in proper neuronal function and maintenance. The identified IRF2BPL nonsense variants behave as severe loss-of-function alleles in this model organism, and ectopic expression of the missense variants leads to a range of phenotypes. Taken together, our results show that IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.

Phenotypic expansion of CACNA1C-associated disorders to include isolated neurological manifestations.

PURPOSE: CACNA1C encodes the alpha-1-subunit of a voltage-dependent L-type calcium channel expressed in human heart and brain. Heterozygous variants in CACNA1C have previously been reported in association with Timothy syndrome and long QT syndrome. Several case reports have suggested that CACNA1C variation may also be associated with a primarily neurological phenotype. METHODS: We describe 25 individuals from 22 families with heterozygous variants in CACNA1C, who present with predominantly neurological manifestations. RESULTS: Fourteen individuals have de novo, nontruncating variants and present variably with developmental delays, intellectual disability, autism, hypotonia, ataxia, and epilepsy. Functional studies of a subgroup of missense variants via patch clamp experiments demonstrated differential effects on channel function in vitro, including loss of function (p.Leu1408Val), neutral effect (p.Leu614Arg), and gain of function (p.Leu657Phe, p.Leu614Pro). The remaining 11 individuals from eight families have truncating variants in CACNA1C. The majority of these individuals have expressive language deficits, and half have autism. CONCLUSION: We expand the phenotype associated with CACNA1C variants to include neurodevelopmental abnormalities and epilepsy, in the absence of classic features of Timothy syndrome or long QT syndrome.

Neuropathology of murine Sanfilippo D syndrome.

Sanfilippo D syndrome (mucopolysaccharidosis type IIID) is a lysosomal storage disorder caused by the deficiency of N-acetylglucosamine-6-sulfatase (GNS). A mouse model was generated by constitutive knockout of the Gns gene. We studied affected mice and controls at 12, 24, 36, and 48 weeks of age for neuropathological markers of disease in the somatosensory cortex, primary motor cortex, ventral posterior nuclei of the thalamus, striatum, hippocampus, and lateral and medial entorhinal cortex. We found significantly increased immunostaining for glial fibrillary associated protein (GFAP), CD68 (a marker of activated microglia), and lysosomal-associated membrane protein-1 (LAMP-1) in Sanfilippo D mice compared to controls at 12 weeks of age in all brain regions. Intergroup differences were marked for GFAP and CD68 staining, with levels in Sanfilippo D mice consistently above controls at all age groups. Intergroup differences in LAMP-1 staining were more pronounced in 12- and 24-week age groups compared to 36- and 48-week groups, as control animals showed some LAMP-1 staining at later timepoints in some brain regions. We also evaluated the somatosensory cortex, medial entorhinal cortex, reticular nucleus of the thalamus, medial amygdala, and hippocampal hilus for subunit c of mitochondrial ATP synthase (SCMAS). We found a progressive accumulation of SCMAS in most brain regions of Sanfilippo D mice compared to controls by 24 weeks of age. Cataloging the regional neuropathology of Sanfilippo D mice may aid in understanding the disease pathogenesis and designing preclinical studies to test brain-directed treatments.

Biochemical evaluation of intracerebroventricular rhNAGLU-IGF2 enzyme replacement therapy in neonatal mice with Sanfilippo B syndrome.

Mucopolysaccharidosis IIIB (MPS IIIB, Sanfilippo syndrome type B) is caused by a deficiency in α-N-acetylglucosaminidase (NAGLU) activity, which leads to the accumulation of heparan sulfate (HS). MPS IIIB causes progressive neurological decline, with affected patients having an expected lifespan of approximately 20 years. No effective treatment is available. Recent pre-clinical studies have shown that intracerebroventricular (ICV) ERT with a fusion protein of rhNAGLU-IGF2 is a feasible treatment for MPS IIIB in both canine and mouse models. In this study, we evaluated the biochemical efficacy of a single dose of rhNAGLU-IGF2 via ICV-ERT in brain and liver tissue from Naglu-/- neonatal mice. Twelve weeks after treatment, NAGLU activity levels in brain were 0.75-fold those of controls. HS and ß-hexosaminidase activity, which are elevated in MPS IIIB, decreased to normal levels. This effect persisted for at least 4 weeks after treatment. Elevated NAGLU and reduced ß-hexosaminidase activity levels were detected in liver; these effects persisted for up to 4 weeks after treatment. The overall therapeutic effects of single dose ICV-ERT with rhNAGLU-IGF2 in Naglu-/- neonatal mice were long-lasting. These results suggest a potential benefit of early treatment, followed by less-frequent ICV-ERT dosing, in patients diagnosed with MPS IIIB.

Enzyme Replacement Therapy for Mucopolysaccharidosis IIID using Recombinant Human α-N-Acetylglucosamine-6-Sulfatase in Neonatal Mice.

There is currently no cure or effective treatment available for mucopolysaccharidosis type IIID (MPS IIID, Sanfilippo syndrome type D), a lysosomal storage disorder (LSD) caused by the deficiency of α-N-acetylglucosamine-6-sulfatase (GNS). The clinical symptoms of MPS IIID, like other subtypes of Sanfilippo syndrome, are largely localized to the central nervous system (CNS), and any treatments aiming to ameliorate or reverse the catastrophic and fatal neurologic decline caused by this disease need to be delivered across the blood-brain barrier. Here, we report a proof-of-concept enzyme replacement therapy (ERT) for MPS IIID using recombinant human α-N-acetylglucosamine-6-sulfatase (rhGNS) via intracerebroventricular (ICV) delivery in a neonatal MPS IIID mouse model. We overexpressed and purified rhGNS from CHO cells with a specific activity of 3.9 × 104 units/mg protein and a maximal enzymatic activity at lysosomal pH (pH 5.6), which was stable for over one month at 4 °C in artificial cerebrospinal fluid (CSF). We demonstrated that rhGNS was taken up by MPS IIID patient fibroblasts via the mannose 6-phosphate (M6P) receptor and reduced intracellular glycosaminoglycans to normal levels. The delivery of 5 µg of rhGNS into the lateral cerebral ventricle of neonatal MPS IIID mice resulted in normalization of the enzymatic activity in brain tissues; rhGNS was found to be enriched in lysosomes in MPS IIID-treated mice relative to the control. Furthermore, a single dose of rhGNS was able to reduce the accumulated heparan sulfate and ß-hexosaminidase. Our results demonstrate that rhGNS delivered into CSF is a potential therapeutic option for MPS IIID that is worthy of further development.

Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic or likely pathogenic variants associated with increased risk of breast, ovarian, and pancreatic cancer and recommended approaches to genetic testing/counseling and management strategies in individuals with these pathogenic or likely pathogenic variants. This manuscript focuses on cancer risk and risk management for BRCA-related breast/ovarian cancer syndrome and Li-Fraumeni syndrome. Carriers of a BRCA1/2 pathogenic or likely pathogenic variant have an excessive risk for both breast and ovarian cancer that warrants consideration of more intensive screening and preventive strategies. There is also evidence that risks of prostate cancer and pancreatic cancer are elevated in these carriers. Li-Fraumeni syndrome is a highly penetrant cancer syndrome associated with a high lifetime risk for cancer, including soft tissue sarcomas, osteosarcomas, premenopausal breast cancer, colon cancer, gastric cancer, adrenocortical carcinoma, and brain tumors.

Mucopolysaccharidoses type I gene therapy.

Mucopolysaccharidoses type I (MPS I) is an inherited metabolic disease characterized by a malfunction of the α-l-iduronidase (IDUA) enzyme leading to the storage of glycosaminoglycans in the lysosomes. This disease has longtime been studied as a therapeutic target for those studying gene therapy and many studies have been done using various vectors to deliver the IDUA gene for corrective treatment. Many vectors have difficulties with efficacy and insertional mutagenesis concerns including adeno-associated viral (AAV) vectors. Studies of AAV vectors treating MPS I have seemed promising, but recent deaths in gene therapy clinical trials for other inherited diseases using AAV vectors have left questions about their safety. Additionally, the recent modifications to adenoviral vectors leading them to target the vascular endothelium minimizing the risk of hepatotoxicity could lead to them being a viable option for MPS I gene therapy when coupled with gene editing technologies like CRISPR/Cas9.

Patient gender does not influence referral to an orthopaedic surgeon by advanced practice orthopaedic providers: a prospective observational study in Canada.

BACKGROUND: The role of an advanced practice physiotherapist has been introduced in many countries to improve access to care for patients with hip and knee arthritis. Traditional models of care have shown a gender bias, with women less often referred and recommended for surgery than men. This study sought to understand if patient gender affects access to care in the clinical encounter with the advanced practice provider. Our objectives were: (1) To determine if a gender difference exists in the clinical decision to offer a consultation with a surgeon; (2) To determine if a gender difference exists in patients' decisions to accept a consultation with a surgeon among those patients to whom it is offered; and, (3) To describe patients' reasons for not accepting a consultation with a surgeon. METHODS: This was a prospective study of 815 patients presenting to a tertiary care centre for assessment of hip and knee arthritis, with referral onward to an orthopaedic surgeon when indicated. We performed a multiple logistic regression analysis adjusting for severity to address the first objective and a simple logistic regression analysis to answer the second objective. Reasons for not accepting a surgical consultation were obtained by questionnaire. RESULTS: Eight hundred and fifteen patients (511 women, 304 men) fulfilled study eligibility criteria. There was no difference in the probability of being referred to a surgeon for men and women (difference adjusted for severity = - 0.02, 95% CI: - 0.07, 0.02). Neither was there a difference in the acceptance of a referral for men and women (difference = - 0.05, 95% CI: - 0.09, 0.00). Of the 14 reasons for declining a surgical consultation, 5 showed a difference with more women than men indicating a preference for non-surgical treatment along with fears/concerns about surgery. CONCLUSIONS: There is no strong evidence to suggest there is a difference in proportion of males and females proceeding to surgical consultation in the model of care that utilizes advanced practice orthopaedic providers in triage. This study adds to the evidence that supports the use of suitably trained alternate providers in roles that reduce wait times to care and add value in contexts where health human resources are limited. The care model is a viable strategy to assist in managing the growing backlog in orthopaedic care, recently exacerbated by the COVID-19 pandemic.

Evaluation of non-reducing end pathologic glycosaminoglycan detection method for monitoring therapeutic response to enzyme replacement therapy in human mucopolysaccharidosis I.

Therapeutic development and monitoring require demonstration of effects on disease phenotype. However, due to the complexity of measuring clinically-relevant effects in rare multisystem diseases, robust biomarkers are essential. For the mucopolysaccharidoses (MPS), the measurement of glycosaminoglycan levels is relevant as glycosaminoglycan accumulation is the primary event that occurs due to reduced lysosomal enzyme activity. Traditional dye-based assays that measure total glycosaminoglycan levels have a high background, due to a normal, baseline glycosaminoglycan content in unaffected individuals. An assay that selectively detects the disease-specific non-reducing ends of heparan sulfate glycosaminoglycans that remain undegraded due to deficiency of a specific enzyme in the catabolic pathway avoids the normal background, increasing sensitivity and specificity. We evaluated glycosaminoglycan content by dye-based and non-reducing end methods using urine, serum, and cerebrospinal fluid from MPS I human samples before and after treatment with intravenous recombinant human alpha-l-iduronidase. We found that both urine total glycosaminoglycans and serum heparan sulfate derived non-reducing end levels were markedly decreased compared to baseline after 26 weeks and 52 weeks of therapy, with a significantly greater percentage reduction in serum non-reducing end (89.8% at 26 weeks and 81.3% at 52 weeks) compared to urine total glycosaminoglycans (68.3% at 26 weeks and 62.4% at 52 weeks, p < 0.001). Unexpectedly, we also observed a decrease in non-reducing end levels in cerebrospinal fluid in all five subjects for whom samples were collected (mean 41.8% reduction, p = 0.01). The non-reducing ends in cerebrospinal fluid showed a positive correlation with serum non-reducing end levels in the subjects (r2 = 0.65, p = 0.005). Results suggest utility of the non-reducing end assay in evaluating a therapeutic response in MPS I.

Intrathecal enzyme replacement for cognitive decline in mucopolysaccharidosis type I, a randomized, open-label, controlled pilot study.

Central nervous system manifestations of mucopolysaccharidosis type I (MPS I) such as cognitive impairment, hydrocephalus, and spinal cord compression are inadequately treated by intravenously-administered enzyme replacement therapy with laronidase (recombinant human alpha-L-iduronidase). While hematopoietic stem cell transplantation treats neurological symptoms, this therapy is not generally offered to attenuated MPS I patients. This study is a randomized, open-label, controlled pilot study of intrathecal laronidase in eight attenuated MPS I patients with cognitive impairment. Subjects ranged between 12 years and 50 years old with a median age of 18 years. All subjects had received intravenous laronidase prior to the study over a range of 4 to 10 years, with a mean of 7.75 years. Weekly intravenous laronidase was continued throughout the duration of the study. The randomization period was one year, during which control subjects attended all study visits and assessments, but did not receive any intrathecal laronidase. After the first year, all eight subjects received treatment for one additional year. There was no significant difference in neuropsychological assessment scores between control or treatment groups, either over the one-year randomized period or at 18 or 24 months. However, there was no significant decline in scores in the control group either. Adverse events included pain (injection site, back, groin), headache, neck spasm, and transient blurry vision. There were seven serious adverse events, one judged as possibly related (headache requiring hospitalization). There was no significant effect of intrathecal laronidase on cognitive impairment in older, attenuated MPS I patients over a two-year treatment period. A five-year open-label extension study is underway.

Phenotypic expansion of KMT2D-related disorder: Beyond Kabuki syndrome.

Pathogenic variants in KMT2D, which encodes lysine specific methyltransferase 2D, cause autosomal dominant Kabuki syndrome, associated with distinctive dysmorphic features including arched eyebrows, long palpebral fissures with eversion of the lower lid, large protuberant ears, and fetal finger pads. Most disease-causing variants identified to date are putative loss-of-function alleles, although 15-20% of cases are attributed to missense variants. We describe here four patients (including one previously published patient) with de novo KMT2D missense variants and with shared but unusual clinical findings not typically seen in Kabuki syndrome, including athelia (absent nipples), choanal atresia, hypoparathyroidism, delayed or absent pubertal development, and extreme short stature. These individuals also lack the typical dysmorphic facial features found in Kabuki syndrome. Two of the four patients had severe interstitial lung disease. All of these variants cluster within a 40-amino-acid region of the protein that is located just N-terminal of an annotated coiled coil domain. These findings significantly expand the phenotypic spectrum of features associated with variants in KMT2D beyond those seen in Kabuki syndrome and suggest a possible new underlying disease mechanism for these patients.

NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 1.2020.

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic provide recommendations for genetic testing and counseling for hereditary cancer syndromes, and risk management recommendations for patients who are diagnosed with syndromes associated with an increased risk of these cancers. The NCCN panel meets at least annually to review comments, examine relevant new data, and reevaluate and update recommendations. These NCCN Guidelines Insights summarize the panel's discussion and most recent recommendations regarding criteria for high-penetrance genes associated with breast and ovarian cancer beyond BRCA1/2, pancreas screening and genes associated with pancreatic cancer, genetic testing for the purpose of systemic therapy decision-making, and testing for people with Ashkenazi Jewish ancestry.

Intrathecal enzyme replacement for Hurler syndrome: biomarker association with neurocognitive outcomes.

PURPOSE: Abnormalities in cerebrospinal fluid (CSF) have been reported in Hurler syndrome, a fatal neurodegenerative lysosomal disorder. While no biomarker has predicted neurocognitive response to treatment, one of these abnormalities, glycosaminoglycan nonreducing ends (NREs), holds promise to monitor therapeutic efficacy. A trial of intrathecal enzyme replacement therapy (ERT) added to standard treatment enabled tracking of CSF abnormalities, including NREs. We evaluated safety, biomarker response, and neurocognitive correlates of change. METHODS: In addition to intravenous ERT and hematopoietic cell transplantation, patients (N = 24) received intrathecal ERT at four peritransplant time points; CSF was evaluated at each point. Neurocognitive functioning was quantified at baseline, 1 year, and 2 years posttransplant. Changes in CSF biomarkers and neurocognitive function were evaluated for an association. RESULTS: Over treatment, there were significant decreases in CSF opening pressure, biomarkers of disease activity, and markers of inflammation. Percent decrease in NRE from pretreatment to final intrathecal dose posttransplant was positively associated with percent change in neurocognitive score from pretreatment to 2 years posttransplant. CONCLUSION: Intrathecal ERT was safe and, in combination with standard treatment, was associated with reductions in CSF abnormalities. Critically, we report evidence of a link between a biomarker treatment response and neurocognitive outcome in Hurler syndrome.

Macrophage enzyme and reduced inflammation drive brain correction of mucopolysaccharidosis IIIB by stem cell gene therapy.

Mucopolysaccharidosis IIIB is a paediatric lysosomal storage disease caused by deficiency of the enzyme α-N-acetylglucosaminidase (NAGLU), involved in the degradation of the glycosaminoglycan heparan sulphate. Absence of NAGLU leads to accumulation of partially degraded heparan sulphate within lysosomes and the extracellular matrix, giving rise to severe CNS degeneration with progressive cognitive impairment and behavioural problems. There are no therapies. Haematopoietic stem cell transplant shows great efficacy in the related disease mucopolysaccharidosis I, where donor-derived monocytes can transmigrate into the brain following bone marrow engraftment, secrete the missing enzyme and cross-correct neighbouring cells. However, little neurological correction is achieved in patients with mucopolysaccharidosis IIIB. We have therefore developed an ex vivo haematopoietic stem cell gene therapy approach in a mouse model of mucopolysaccharidosis IIIB, using a high-titre lentiviral vector and the myeloid-specific CD11b promoter, driving the expression of NAGLU (LV.NAGLU). To understand the mechanism of correction we also compared this with a poorly secreted version of NAGLU containing a C-terminal fusion to IGFII (LV.NAGLU-IGFII). Mucopolysaccharidosis IIIB haematopoietic stem cells were transduced with vector, transplanted into myeloablated mucopolysaccharidosis IIIB mice and compared at 8 months of age with mice receiving a wild-type transplant. As the disease is characterized by increased inflammation, we also tested the anti-inflammatory steroidal agent prednisolone alone, or in combination with LV.NAGLU, to understand the importance of inflammation on behaviour. NAGLU enzyme was substantially increased in the brain of LV.NAGLU and LV.NAGLU-IGFII-treated mice, with little expression in wild-type bone marrow transplanted mice. LV.NAGLU treatment led to behavioural correction, normalization of heparan sulphate and sulphation patterning, reduced inflammatory cytokine expression and correction of astrocytosis, microgliosis and lysosomal compartment size throughout the brain. The addition of prednisolone improved inflammatory aspects further. Substantial correction of lysosomal storage in neurons and astrocytes was also achieved in LV.NAGLU-IGFII-treated mice, despite limited enzyme secretion from engrafted macrophages in the brain. Interestingly both wild-type bone marrow transplant and prednisolone treatment alone corrected behaviour, despite having little effect on brain neuropathology. This was attributed to a decrease in peripheral inflammatory cytokines. Here we show significant neurological disease correction is achieved using haematopoietic stem cell gene therapy, suggesting this therapy alone or in combination with anti-inflammatories may improve neurological function in patients.

myHip&Knee: Improving Patient Engagement and Self-Management Through Mobile Technology.

Given the increasing volume of hip and knee replacement surgery with reduced hospital stays and resources, we explored technology to address gaps in patient care and enhance self-management. The team at the Holland Orthopaedic and Arthritic Centre of Sunnybrook Health Sciences Centre, which performs a high volume of joint replacement surgery, partnered with patients and a health technology company to create a mobile app: myHip&Knee. The results to date demonstrate that the app improves patient experience and reduces follow-up calls to surgeons' offices, ultimately reducing demand on healthcare resources. Early engagement of privacy and legal services, close patient and family collaboration and a well-developed evaluation strategy represent critical steps to successful development.

Community Partnership in Precision Medicine: Themes from a Community Engagement Conference.

Background: Patient and community engagement in under-resourced communities is a key issue for precision medicine research. We report proceedings from a community-academic partnered conference in Los Angeles to promote community understanding of precision medicine and generate engagement recommendations. Methods: Planning group review of planning, presentations, and audience discussions from facilitator notes and participant survey data from a one-day conference. Findings: Community-academic planning broadened community participation and presentations. More than 80% of survey participants indicated they would participate in the national precision medicine initiative, and most were willing to share diverse sources of data. Discussions identified trust concerns related to historical research abuses, data privacy, potential effects of findings on health care, personal safety, research procedures, the time-frame for benefit, and confusion about different initiatives. Concerns were balanced by belief in science to improve health. Recommendations included a community partnered participatory approach with support for local community and academic teams to engage stakeholders with written/online resources and partnered workgroups addressing key concerns. Conclusion: Conference participants expressed high willingness to participate in precision medicine studies, but discussions highlighted trust and transparency issues and suggested community partnered research with local capacity building.