- Email: [email protected]
66. Development of a disease severity scoring system for patients with Pompe disease
S30
Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46
altered lysosomal pH) suggesting that storage in this disease is caused by abnormal transport of lipids out of late endosomes or lysosomes. MLIV is caused by mutations in the MCOLN1 gene encoding the TRP-ML1 putative cation channel believed to be involved in lysosomal calcium and/or proton transport. At present there is no consensus on the exact function of this channel. Using highly sensitive microscopy methods, we have measured lysosomal pH and calcium homeostasis in MLIV fibroblasts. We have found that MLIV cells have frequent and continuous spontaneous calcium release from lysosomes (whereas normal cells have far fewer lysosomal calcium release events). This altered calcium release is associated with increased late endosome-lysosome fusion and potentially inhibits their subsequent reformation. Treatment of MLIV cells with NB-DNJ lowers glycosphingolipid storage and leads to a partial correction of the calcium phenotype, suggesting some involvement of the storage material in exacerbating the primary underlying phenotype. We propose that the TRP-ML1 channel is involved in maintaining normal lysosomal calcium homeostasis, potentially via the NAADP receptor. doi:10.1016/j.ymgme.2007.10.074
63. Pharmacological chaperone treatment for lysosomal storage disorders David Lockhart, Amicus Therapeutics, Cranbury, NJ, USA Lysosomal storage disorders are caused by genetic mutations that lead to a reduction of essential enzymatic activity. In many cases the mutated forms of the enzymes are functionally competent but less stable and are not trafficked efficiently from the endoplasmic reticulum to the lysosomes. Pharmacological chaperones are small molecules designed to mitigate this problem by specifically binding and stabilizing the target enzyme, thus reducing premature protein degradation and increasing lysosomal enzyme concentrations and cellular activity. We have developed different pharmacological chaperones (PCs) for Fabry, Gaucher and Pompe diseases, and all are currently being tested in clinical trials: AT1001 for Fabry in Phase 2, AT2101 for Gaucher in Phase 2 and AT2220 for Pompe in Phase 1. We have shown that the PCs bind specifically to their target enzyme and that binding increases protein stability. The PCs increase cellular enzyme levels for multiple mutant forms of each enzyme, as tested using cell lines derived from patients with different mutations and cells transfected with specific mutant forms. The PCs are orally available and well-tolerated in animals and humans, and they have broad biodistribution into many cell types and tissues. In a Fabry transgenic mouse model that accumulates substrate, AT1001 administration was shown to reduce substrate levels in plasma and in key tissues such as the heart, skin and brain. These results indicate that PCs represent a promising new approach and that the specific molecules AT1001, AT2101 and AT2220 merit further evaluation as treatments for patients with lysosomal storage disorders.
genes (GFP or luciferase) after intraventricular injections into adult or neonatal mice. Intraventricular injections of lenti-GFP resulted in the labeling of cells immediately surrounding the ventricles, but few cells were observed in the olfactory bulb, the primary destination of migrating stem cells from the SVZ. Intraventricular injections of SB-luciferase also resulted in a modest labeling of cells in the subventricular zone. In contrast, intraventricular injections of AAV5-GFP resulted in a robust labeling of cells in the SVZ and the olfactory bulb as well as other areas of brain. These results suggest that AAV5 appears to exhibit a greater tropism for neural stem cells in the SVZ when injected into the lateral ventricles in comparison to other vector systems. doi:10.1016/j.ymgme.2007.10.076
65. Identification of Ambroxol as a potential enzyme enhancement-agent for Gaucher disease Don Mahuran a, Gustavo Maegawa a, Michael Tropak a, Justin Butner a, Gregory Kornhaber b, Brigitte Rigat a, Joe Clarke a, a Hospital For Sick Children, Toronto, ON, Canada, b ExSAR Corporation, Canada Gaucher disease, currently treated by enzyme replacement therapy (ERT), is caused by a deficiency of lysosomal beta-glucosidase (GCase). The disadvantages of ERT include its high cost, its ineffectiveness in treating the CNS or other organ compartments and the unfolded protein response in cells. Small molecule-based enzyme enhancement therapy (EET) is a promising approach that can potentially be used alone or in combination with ERT to address these deficiencies. Clinical trials of isofagomine, an inhibitor of GCase (IC50 0.04 lM), as an EET-agent are being initiated. In order to accelerate the process of obtaining IND-status for new EET-agents we have screened the NINDS library of FDAapproved drugs for compounds that inhibit and/or stabilize the target enzyme towards heat denaturation. Using GCase as the target we identified Ambroxol, an expectorant, as a candidate EET-agent. Despite Ambroxol being only a weak inhibitor of GCase, IC50 = 27 lM, at higher concentrations it compared favorably with isofagomine in its ability to rescue mutant N370S GCase in patient cells. However, it was not as effective at rescuing F213I GCase. Hydrogen–Deuterium exchange Mass Spectrometry (H/D-Ex) was used to compare the regions in GCase that were stabilized by these compounds. Isofagomine has been shown through co-crystallization to stabilize a loop structure at GCase352–357. H/D-Ex confirmed these data, while Ambroxol was ineffective at stabilizing this loop. However, both compounds were equally effective in stabilizing another region, GCase283–288, indicating its importance as a target for EET-agents. doi:10.1016/j.ymgme.2007.10.077
doi:10.1016/j.ymgme.2007.10.075
64. Targeting neural stem cells in the mammalian brain with intraventricular injections of lenti, AAV5, or Sleeping Beauty vectors Walter Low, Terry Burns, Catherine Verfaillie, Perry Hackett, Chet Whitley, Zhenghong Nan, Feng Xiao, Lalitha Belur, Zach Demorest, Dan Wolf, John Ohlfest, Scott McIvor, University of Minnesota, Minneapolis, MN, USA Neural stem cells (NSCs) in the mammalian brain reside in the subventricular zone (SVZ) where they proliferate within this stem cell niche. Upon induction NSCs migrate to other regions of the brain and differentiate into neurons and astrocytes. NSCs therefore represent a target for gene therapy that might provide a wide spread distribution to therapeutic compounds to distant regions of the brain. We have examined the distribution of lenti, AAV5, or Sleeping Beauty vectors that express reporter
66. Development of a disease severity scoring system for patients with Pompe disease Deborah Marsden a, Kenneth Berger b, Ans van der Ploeg c, Laura Case d, Christopher Dandrea a, Priya Kishnani d, Edward Giannini e, a Genzyme Corporation, Cambridge, MA, USA, b NYU School of Medicine, New York, NY, USA, c Erasmus MC-Sophia, Rotterdam, The Netherlands, d Duke University Medical Center, Durham, NC, USA, e Cincinatti Children’s Hospital, Cincinatti, OH, USA Introduction: A Disease Severity Scoring System (DS3) measures disease burden in patients. It consists of critical health domains, each described by relevant clinical assessment(s) quantified via reliable, feasible methods. DS3s are particularly useful in rare, heterogeneous diseases in which evaluating severity and prognosis is difficult. Properly configured, a DS3 provides inter- and intra-patient comparisons through time across critical organ systems. Development is underway for Pompe disease, a rare, autosomal recessive, heterogenous, neuromuscular disorder.
Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46
S31
Description: A panel of Pompe experts was assembled to identify critical Pompe disease health domains. A broader ‘‘Delphi’’ physician group was consulted to capture standard medical practice(s) for severity measurement within each critical domain. Selected domains were: Cardiac, Respiratory, Proximal Muscle, Physician Reported Outcomes and Patient Reported Outcomes. Within each domain, 1–2 clinical assessments were identified. To test this preliminary model, 9 cases from the Pompe Registry representing a severity spectrum were scored. Results: Results were compared to results from a blinded small expert group assessment of the cases using the Clinical Global Impression (CGI) Severity scale, yielding a 0.93 coefficient of correlation, indicating preliminary DS3 consistency with expert opinion, confirming DS3 validity, reliability and relevance. Validation will be completed by comparing DS3 results with expert ‘‘Delphi group’’ opinion for multiple patient cases at multiple time points. Conclusion: Preliminary results indicate the Pompe DS3 model will help standardize disease terminology, highlight key clinical assessments to quantify disease severity. Ultimately this tool will evolve into a universal disease ‘‘staging’’ system where specific medical interventions may be recommended.
Fabry disease. We report here the bone density scores and clinical findings relative to the skeleton in a series of 35 patients with Type B NPD. Within the NPD pediatric cohort, 7 of 18 subjects had suffered a skeletal fracture including one patient who had multiple fractures of her lower extremities beginning at the age of 14 mos. Among the adults studied 9 of 17 patients had suffered a fracture including two premonpausal women with vertebral fractures. Statistically significant decreases were observed in BMC (gm) and BMD (gm/cm2) of the lumbar spine, hip, and femoral neck between the pediatric NPD cohort and control subjects with analysis of covariance adjusting for age, weight, height, Tanner stage, and sex. Among the adult subjects, most were osteopenic or osteoporotic at one or more sites according the WHO classification of BMD. These data document that abnormal bone density and osteoporosis are a common clinical feature of NPD. In addition, analysis of data related to bone resorption and formation biochemical parameters will be presented which are suggestive of dysregulated osteoclast activity in patients with NPD.
doi:10.1016/j.ymgme.2007.10.078
69. Gene therapy of mucopolysaccharidosis type I: Intraventricular administration of adeno-associated virus vector transducing the human alpha-Liduronidase gene in a murine model of the disease R. Scott McIvor a, Daniel A. Wolf a, Zhenhong Nan b, Mayra Quito b, Kelly Podetz-Pedersen a, Chester B. Whitley c, Walter C. Low b, Lalitha R. Belur a, a Institute of Human Genetics, Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA, b Department of Neurosurgery, University of Minnesota, USA, c Department of Pediatrics, University of Minnesota, USA
67. Newborn screening for lysosomal storage diseases: Issues and concerns Deborah Marsden, Cambridge, MA, USA Background: newborn screening for inborn errors of metabolism is a public health initiative widely adopted in the developed world. Traditionally, screened disorders have met modified Wilson and Junger criteria, including prevalence, benefit of early therapeutic intervention on long term outcomes and availability of a high throughput screening test. Screening panels are usually determined by state or regional advisory committees and vary with availability of local resources, including funding sources and adequate specialized medical follow up. Development of new technology (tandem mass spectrometry) has resulted in greatly expanded panels for rare inborn errors of metabolism in some, but not all areas. A uniform panel and follow up protocols have not yet been fully adopted. Current situation: new technology is now available for several lysosomal storage disorders (LSDs), either as single or multiplexed enzyme assays. Clinical trial outcomes show efficacy of intervention with enzyme replacement therapy in many patients, though long term data are not yet available. Pilot programs are currently ongoing for several LSDs. Discussion: many issues need to be resolved, including, which disorders to include in screening panels; the need for informed consent; development of uniform protocols for evaluation, confirmation and follow up after an abnormal screening result; when to initiate therapy in later presenting variants; long term follow up of therapeutic intervention; ethical concerns and the effect on the family when a late-presenting disorder is diagnosed in newborns. Conclusion: an international effort is necessary to develop appropriate guidelines. doi:10.1016/j.ymgme.2007.10.079
68. Skeletal mainfestations in Niemann–Pick disease due to acid sphingomyelinase deficiency Margaret McGovern a, Melissa Wasserstein b, a Stony Brook University, Stony Brook, NY, USA, b Mount Sinai School of Medicine, USA Studies to determine the involvement of the skeleton in Niemann–Pick disease (NPD) due to acid sphingomyelinase deficiency have not been reported. In contrast, in Gaucher disease skeletal involvement is known to be a common clinical feature and osteopenia and osteoporosis have recently been reported as a previously unrecognized manifestation in
doi:10.1016/j.ymgme.2007.10.080
Mucopolysaccharidosis type I is an autosomal recessive disorder caused by deficiency of alpha-L-iduronidase (IDUA). Resultant lysosomal accumulation of glycosaminoglycans dermatan sulphate and heparan sulphate is associated with organomegaly, skeletal dysplasia, cardiopulmonary obstruction and, in the severe form of the disease (Hurler syndrome), neurological deterioration. The successes of allogeneic stem cell transplantation and infused recombinant enzyme suggest that the disease may also be effectively treated by introduction and expression of the IDUA gene in tissues of the affected individual. Adeno-associated virus (AAV) vectors have been shown to be highly effective in mediating gene transfer to a variety of tissues, including tissues of the central nervous system, with potential for therapeutic application. Previously, we reported that intravenous administration of IDUA vectors based on AAV serotype 2 to newborn mice deficient in IDUA activity resulted in widespread expression of IDUA activity and prevented the emergence of metabolic, craniofacial, and neurological manifestations of the disease (Molecular Therapy 9: 866, 2004). Our current studies are focused on extending the applicability of AAV-mediated IDUA gene transfer to adult mice by direct administration of vector to the central nervous system. Recently, we have found that widely disseminated transduction can be achieved in the mouse brain after a single intraventricular infusion of AAV serotype 5 vector, and that distribution is further facilitated by prior intravenous administration of mannitol. To test the effectiveness of this approach in a therapeutic gene transfer setting, young adult MPS I mice were infused with 25% mannitol i.v. and then injected intraventricularly with AAV serotype 5 vector engineered for expression of both human IDUA and GFP. These animals are being evaluated in comparison with normal and affected control mice for improved neurologic function, and will also be evaluated for IDUA enzymatic activity and prevention of storage accumulation in the central nervous system resulting from AAV-IDUA transduction. It is anticipated that results from these studies will provide an assessment of AAV mediated intraventricular delivery combined with mannitol administration in attenuating brain disease observed in MPS I and potentially other lysosomal storage diseases. doi:10.1016/j.ymgme.2007.10.081
Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46
altered lysosomal pH) suggesting that storage in this disease is caused by abnormal transport of lipids out of late endosomes or lysosomes. MLIV is caused by mutations in the MCOLN1 gene encoding the TRP-ML1 putative cation channel believed to be involved in lysosomal calcium and/or proton transport. At present there is no consensus on the exact function of this channel. Using highly sensitive microscopy methods, we have measured lysosomal pH and calcium homeostasis in MLIV fibroblasts. We have found that MLIV cells have frequent and continuous spontaneous calcium release from lysosomes (whereas normal cells have far fewer lysosomal calcium release events). This altered calcium release is associated with increased late endosome-lysosome fusion and potentially inhibits their subsequent reformation. Treatment of MLIV cells with NB-DNJ lowers glycosphingolipid storage and leads to a partial correction of the calcium phenotype, suggesting some involvement of the storage material in exacerbating the primary underlying phenotype. We propose that the TRP-ML1 channel is involved in maintaining normal lysosomal calcium homeostasis, potentially via the NAADP receptor. doi:10.1016/j.ymgme.2007.10.074
63. Pharmacological chaperone treatment for lysosomal storage disorders David Lockhart, Amicus Therapeutics, Cranbury, NJ, USA Lysosomal storage disorders are caused by genetic mutations that lead to a reduction of essential enzymatic activity. In many cases the mutated forms of the enzymes are functionally competent but less stable and are not trafficked efficiently from the endoplasmic reticulum to the lysosomes. Pharmacological chaperones are small molecules designed to mitigate this problem by specifically binding and stabilizing the target enzyme, thus reducing premature protein degradation and increasing lysosomal enzyme concentrations and cellular activity. We have developed different pharmacological chaperones (PCs) for Fabry, Gaucher and Pompe diseases, and all are currently being tested in clinical trials: AT1001 for Fabry in Phase 2, AT2101 for Gaucher in Phase 2 and AT2220 for Pompe in Phase 1. We have shown that the PCs bind specifically to their target enzyme and that binding increases protein stability. The PCs increase cellular enzyme levels for multiple mutant forms of each enzyme, as tested using cell lines derived from patients with different mutations and cells transfected with specific mutant forms. The PCs are orally available and well-tolerated in animals and humans, and they have broad biodistribution into many cell types and tissues. In a Fabry transgenic mouse model that accumulates substrate, AT1001 administration was shown to reduce substrate levels in plasma and in key tissues such as the heart, skin and brain. These results indicate that PCs represent a promising new approach and that the specific molecules AT1001, AT2101 and AT2220 merit further evaluation as treatments for patients with lysosomal storage disorders.
genes (GFP or luciferase) after intraventricular injections into adult or neonatal mice. Intraventricular injections of lenti-GFP resulted in the labeling of cells immediately surrounding the ventricles, but few cells were observed in the olfactory bulb, the primary destination of migrating stem cells from the SVZ. Intraventricular injections of SB-luciferase also resulted in a modest labeling of cells in the subventricular zone. In contrast, intraventricular injections of AAV5-GFP resulted in a robust labeling of cells in the SVZ and the olfactory bulb as well as other areas of brain. These results suggest that AAV5 appears to exhibit a greater tropism for neural stem cells in the SVZ when injected into the lateral ventricles in comparison to other vector systems. doi:10.1016/j.ymgme.2007.10.076
65. Identification of Ambroxol as a potential enzyme enhancement-agent for Gaucher disease Don Mahuran a, Gustavo Maegawa a, Michael Tropak a, Justin Butner a, Gregory Kornhaber b, Brigitte Rigat a, Joe Clarke a, a Hospital For Sick Children, Toronto, ON, Canada, b ExSAR Corporation, Canada Gaucher disease, currently treated by enzyme replacement therapy (ERT), is caused by a deficiency of lysosomal beta-glucosidase (GCase). The disadvantages of ERT include its high cost, its ineffectiveness in treating the CNS or other organ compartments and the unfolded protein response in cells. Small molecule-based enzyme enhancement therapy (EET) is a promising approach that can potentially be used alone or in combination with ERT to address these deficiencies. Clinical trials of isofagomine, an inhibitor of GCase (IC50 0.04 lM), as an EET-agent are being initiated. In order to accelerate the process of obtaining IND-status for new EET-agents we have screened the NINDS library of FDAapproved drugs for compounds that inhibit and/or stabilize the target enzyme towards heat denaturation. Using GCase as the target we identified Ambroxol, an expectorant, as a candidate EET-agent. Despite Ambroxol being only a weak inhibitor of GCase, IC50 = 27 lM, at higher concentrations it compared favorably with isofagomine in its ability to rescue mutant N370S GCase in patient cells. However, it was not as effective at rescuing F213I GCase. Hydrogen–Deuterium exchange Mass Spectrometry (H/D-Ex) was used to compare the regions in GCase that were stabilized by these compounds. Isofagomine has been shown through co-crystallization to stabilize a loop structure at GCase352–357. H/D-Ex confirmed these data, while Ambroxol was ineffective at stabilizing this loop. However, both compounds were equally effective in stabilizing another region, GCase283–288, indicating its importance as a target for EET-agents. doi:10.1016/j.ymgme.2007.10.077
doi:10.1016/j.ymgme.2007.10.075
64. Targeting neural stem cells in the mammalian brain with intraventricular injections of lenti, AAV5, or Sleeping Beauty vectors Walter Low, Terry Burns, Catherine Verfaillie, Perry Hackett, Chet Whitley, Zhenghong Nan, Feng Xiao, Lalitha Belur, Zach Demorest, Dan Wolf, John Ohlfest, Scott McIvor, University of Minnesota, Minneapolis, MN, USA Neural stem cells (NSCs) in the mammalian brain reside in the subventricular zone (SVZ) where they proliferate within this stem cell niche. Upon induction NSCs migrate to other regions of the brain and differentiate into neurons and astrocytes. NSCs therefore represent a target for gene therapy that might provide a wide spread distribution to therapeutic compounds to distant regions of the brain. We have examined the distribution of lenti, AAV5, or Sleeping Beauty vectors that express reporter
66. Development of a disease severity scoring system for patients with Pompe disease Deborah Marsden a, Kenneth Berger b, Ans van der Ploeg c, Laura Case d, Christopher Dandrea a, Priya Kishnani d, Edward Giannini e, a Genzyme Corporation, Cambridge, MA, USA, b NYU School of Medicine, New York, NY, USA, c Erasmus MC-Sophia, Rotterdam, The Netherlands, d Duke University Medical Center, Durham, NC, USA, e Cincinatti Children’s Hospital, Cincinatti, OH, USA Introduction: A Disease Severity Scoring System (DS3) measures disease burden in patients. It consists of critical health domains, each described by relevant clinical assessment(s) quantified via reliable, feasible methods. DS3s are particularly useful in rare, heterogeneous diseases in which evaluating severity and prognosis is difficult. Properly configured, a DS3 provides inter- and intra-patient comparisons through time across critical organ systems. Development is underway for Pompe disease, a rare, autosomal recessive, heterogenous, neuromuscular disorder.
Abstracts / Molecular Genetics and Metabolism 93 (2008) S14–S46
S31
Description: A panel of Pompe experts was assembled to identify critical Pompe disease health domains. A broader ‘‘Delphi’’ physician group was consulted to capture standard medical practice(s) for severity measurement within each critical domain. Selected domains were: Cardiac, Respiratory, Proximal Muscle, Physician Reported Outcomes and Patient Reported Outcomes. Within each domain, 1–2 clinical assessments were identified. To test this preliminary model, 9 cases from the Pompe Registry representing a severity spectrum were scored. Results: Results were compared to results from a blinded small expert group assessment of the cases using the Clinical Global Impression (CGI) Severity scale, yielding a 0.93 coefficient of correlation, indicating preliminary DS3 consistency with expert opinion, confirming DS3 validity, reliability and relevance. Validation will be completed by comparing DS3 results with expert ‘‘Delphi group’’ opinion for multiple patient cases at multiple time points. Conclusion: Preliminary results indicate the Pompe DS3 model will help standardize disease terminology, highlight key clinical assessments to quantify disease severity. Ultimately this tool will evolve into a universal disease ‘‘staging’’ system where specific medical interventions may be recommended.
Fabry disease. We report here the bone density scores and clinical findings relative to the skeleton in a series of 35 patients with Type B NPD. Within the NPD pediatric cohort, 7 of 18 subjects had suffered a skeletal fracture including one patient who had multiple fractures of her lower extremities beginning at the age of 14 mos. Among the adults studied 9 of 17 patients had suffered a fracture including two premonpausal women with vertebral fractures. Statistically significant decreases were observed in BMC (gm) and BMD (gm/cm2) of the lumbar spine, hip, and femoral neck between the pediatric NPD cohort and control subjects with analysis of covariance adjusting for age, weight, height, Tanner stage, and sex. Among the adult subjects, most were osteopenic or osteoporotic at one or more sites according the WHO classification of BMD. These data document that abnormal bone density and osteoporosis are a common clinical feature of NPD. In addition, analysis of data related to bone resorption and formation biochemical parameters will be presented which are suggestive of dysregulated osteoclast activity in patients with NPD.
doi:10.1016/j.ymgme.2007.10.078
69. Gene therapy of mucopolysaccharidosis type I: Intraventricular administration of adeno-associated virus vector transducing the human alpha-Liduronidase gene in a murine model of the disease R. Scott McIvor a, Daniel A. Wolf a, Zhenhong Nan b, Mayra Quito b, Kelly Podetz-Pedersen a, Chester B. Whitley c, Walter C. Low b, Lalitha R. Belur a, a Institute of Human Genetics, Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, USA, b Department of Neurosurgery, University of Minnesota, USA, c Department of Pediatrics, University of Minnesota, USA
67. Newborn screening for lysosomal storage diseases: Issues and concerns Deborah Marsden, Cambridge, MA, USA Background: newborn screening for inborn errors of metabolism is a public health initiative widely adopted in the developed world. Traditionally, screened disorders have met modified Wilson and Junger criteria, including prevalence, benefit of early therapeutic intervention on long term outcomes and availability of a high throughput screening test. Screening panels are usually determined by state or regional advisory committees and vary with availability of local resources, including funding sources and adequate specialized medical follow up. Development of new technology (tandem mass spectrometry) has resulted in greatly expanded panels for rare inborn errors of metabolism in some, but not all areas. A uniform panel and follow up protocols have not yet been fully adopted. Current situation: new technology is now available for several lysosomal storage disorders (LSDs), either as single or multiplexed enzyme assays. Clinical trial outcomes show efficacy of intervention with enzyme replacement therapy in many patients, though long term data are not yet available. Pilot programs are currently ongoing for several LSDs. Discussion: many issues need to be resolved, including, which disorders to include in screening panels; the need for informed consent; development of uniform protocols for evaluation, confirmation and follow up after an abnormal screening result; when to initiate therapy in later presenting variants; long term follow up of therapeutic intervention; ethical concerns and the effect on the family when a late-presenting disorder is diagnosed in newborns. Conclusion: an international effort is necessary to develop appropriate guidelines. doi:10.1016/j.ymgme.2007.10.079
68. Skeletal mainfestations in Niemann–Pick disease due to acid sphingomyelinase deficiency Margaret McGovern a, Melissa Wasserstein b, a Stony Brook University, Stony Brook, NY, USA, b Mount Sinai School of Medicine, USA Studies to determine the involvement of the skeleton in Niemann–Pick disease (NPD) due to acid sphingomyelinase deficiency have not been reported. In contrast, in Gaucher disease skeletal involvement is known to be a common clinical feature and osteopenia and osteoporosis have recently been reported as a previously unrecognized manifestation in
doi:10.1016/j.ymgme.2007.10.080
Mucopolysaccharidosis type I is an autosomal recessive disorder caused by deficiency of alpha-L-iduronidase (IDUA). Resultant lysosomal accumulation of glycosaminoglycans dermatan sulphate and heparan sulphate is associated with organomegaly, skeletal dysplasia, cardiopulmonary obstruction and, in the severe form of the disease (Hurler syndrome), neurological deterioration. The successes of allogeneic stem cell transplantation and infused recombinant enzyme suggest that the disease may also be effectively treated by introduction and expression of the IDUA gene in tissues of the affected individual. Adeno-associated virus (AAV) vectors have been shown to be highly effective in mediating gene transfer to a variety of tissues, including tissues of the central nervous system, with potential for therapeutic application. Previously, we reported that intravenous administration of IDUA vectors based on AAV serotype 2 to newborn mice deficient in IDUA activity resulted in widespread expression of IDUA activity and prevented the emergence of metabolic, craniofacial, and neurological manifestations of the disease (Molecular Therapy 9: 866, 2004). Our current studies are focused on extending the applicability of AAV-mediated IDUA gene transfer to adult mice by direct administration of vector to the central nervous system. Recently, we have found that widely disseminated transduction can be achieved in the mouse brain after a single intraventricular infusion of AAV serotype 5 vector, and that distribution is further facilitated by prior intravenous administration of mannitol. To test the effectiveness of this approach in a therapeutic gene transfer setting, young adult MPS I mice were infused with 25% mannitol i.v. and then injected intraventricularly with AAV serotype 5 vector engineered for expression of both human IDUA and GFP. These animals are being evaluated in comparison with normal and affected control mice for improved neurologic function, and will also be evaluated for IDUA enzymatic activity and prevention of storage accumulation in the central nervous system resulting from AAV-IDUA transduction. It is anticipated that results from these studies will provide an assessment of AAV mediated intraventricular delivery combined with mannitol administration in attenuating brain disease observed in MPS I and potentially other lysosomal storage diseases. doi:10.1016/j.ymgme.2007.10.081