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Early intrathecal gene therapy extends lifespan and improves quality of life in a mouse model for infantile neuronal ceroid lipofuscinosis
Abstracts / Molecular Genetics and Metabolism 120 (2016) S17–S145
Gaucher disease (GD) results from the deficiency of glucocerebrosidase. Type 2 GD is the rarest and most severe form. Traditionally, the presentation is considered stereotypic; however symptoms range from hydrops fetalis to the collodion baby phenotype to infants presenting after 6 months of life. Neurological involvement occurs early, resulting in severe degeneration with death in infancy or early childhood. However in the past decade, these infants have been living longer due to more aggressive interventions. The purpose of this study is to delineate the changing clinical course of type 2 GD. For this study we have identified a cohort of living and deceased patients with clinically and molecularly confirmed type 2 GD, We then conduct a structured telephone interview with parents of affected individuals. Medical issues address include disease presentation, disease progression, surgical history, medications, feeding issues, family history, management, complications, hospice care, cause of death and impact of disease on family members. Thus far, the review of 7 recent cases has shown a mean age at death of 26.5 months (ranging from 10 36 months). Four probands were treated with enzyme replacement therapy. All 7 patients received gastrostomy tubes while 3 underwent tracheostomies. Other interventions included treatment with Ambroxol and bone marrow transplantation. Current treatment options, while not curative, appear to be changing the clinical course of type 2 GD. Affected individuals are living longer, but interventions do not appear to markedly impact the neurological manifestations. This study has just begun and is anticipated to highlight newer complications and manifestations. Diagnosing and treating these infants has always been a challenge to clinicians. It is paramount to understand the baseline and any changes in the clinical course. This data is essential in the design of any future interventional protocols, helping identify treatment goals and milestones to determine efficacy.
doi:10.1016/j.ymgme.2016.11.300
292 Early intrathecal gene therapy extends lifespan and improves quality of life in a mouse model for infantile neuronal ceroid lipofuscinosis
S117
stage (4.5 months) extended lifespan by 4 months and delayed the onset of motor deficits by 3.5 months. IT-delivered scAAV9 vectors are currently used in two phase I clinical trials. Our preliminary findings, paired with the early onset and rapid decline in patients, and the already established route of delivery in humans, suggest this approach could be advanced as a treatment for INCL that is likely to provide the most benefit when administered early in the course of the disease. doi:10.1016/j.ymgme.2016.11.301
293 Expression of the lysosomal membrane protein LMBD1 is essential for the initiation of gastrulation Frank Rutscha, Petra Pennekampa, Yvonne Nitschkea, Chrishanthi Lowea, Boris Skryabinb, Insa Buersa, aMuenster University Children's Hospital, Muenster, Germany, bInstitute of Experimental Pathology, Muenster University, Muenster, Germany The rare inborn cblF defect of cobalamin metabolism is caused by mutations in the limb region 1 (LMBR1) domain containing 1 gene (LMBRD1). This defect is characterized by massive accumulation of free cobalamin in lysosomes and loss of mitochondrial succinyl-CoA synthesis and cytosolic methionine synthesis. Affected children suffer from heart defects, developmental delay and megaloblastic anemia. LMBRD1 encodes for LMBD1, a predicted lysosomal cobalamin transport protein. In this study, we determine the physiological function of LMBRD1 during embryogenesis by generating Lmbrd1 deficient mice using the Cre/loxP system. Complete loss of Lmbrd1 function is accompanied with early embryonic lethality in mice. Whole mount in situ hybridization studies against Bmp4 and Nodal show that initial formation of the proximal-distal axis is unaffected in early embryonic stages, whereas the initiation of gastrulation is disturbed shown by the expression pattern of Evx1 and Fgf8 in Lmbrd1 deficient mice. We conclude that intact function of LMBD1 is essential for the initiation of gastrulation. doi:10.1016/j.ymgme.2016.11.302
Alejandra J Rozenberg, Steven J Gray, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States Infantile neuronal ceroid lipofuscinosis (INCL) is a severe lysosomal disease caused by mutations in the CLN1 gene, which encodes the soluble lysosomal enzyme Palmitoyl-Protein-Thioesterase-1 (PPT1). In its absence, osmiophilic granules accumulate in lysosomes, eventually leading to neuroinflammation and neurodegeneration. Onset of symptoms occurs between 6 to 24 months, characterized by progressive visual failure, cognitive and motor decline, seizures and premature death. There is currently no cure, only palliative care. INCL mice recapitulate the major features of the disease; neurological deficits appear by 4.5 months with premature death around 8 months. A single intrathecal (IT) injection of self-complementary adeno-associated virus 9 (scAAV9) encoding the human CLN1 gene at an initial dose of 7x1010 vector genomes per mouse was administered via lumbar puncture to INCL mice at 1 week, 1 month (pre-symptomatic), 4.5 months (earlysymptomatic) or 6 months of age (symptomatic). While treatment at 4.5 months or later did not show therapeutic benefit, mice treated at 1 month survived approximately twice their expected lifespan. Mice treated at 1 week (modeling dosing soon after birth in humans) started showing motor deficits around 15 months and are currently alive, over 18 months of age. A 10-fold higher dose was subsequently tested. Lifespan was extended by 1.5 months in mice treated at the symptomatic stage (6 months). Treatment at the early-symptomatic
294 Structural basis of Hunter syndrome and construction of a database of mutant iduronate 2-sulfatase Hitoshi Sakurabaa, Seiji Saitob, Kazuki Ohnoc, aMeiji Pharmaceutical University, Kiyose, Japan, bHokkaido Information University, Ebetsu, Japan, cTokyo Institute of Technology, Tokyo, Japan Hunter syndrome (HS) is an X-linked genetic disorder caused by a deficiency of iduronate 2-sulfatase (IDS). Gross alterations of the IDS gene lead to the severe phenotype, but missense mutations comprising the majority of the mutations responsible for HS result in heterogeneous phenotypes ranging from the severe to the attenuated type. To elucidate the basis of HS from the structural viewpoint, we built a structural model of human IDS by means of the homology modeling and molecular dynamics methods. The results reveled that IDS consists of alpha/beta folds and the active site is located in the loop region near the N-terminal antiparallel beta-strand. Then we constructed structural models of mutant IDS proteins resulting from 134 missense mutations (phenotypes: 69 severe and 65 attenuated) for which the HS phenotypes have been clearly described, using the predicted wild-type IDS structure as a template. Then we analyzed the influence of each amino acid substitution on the IDS structure by
Gaucher disease (GD) results from the deficiency of glucocerebrosidase. Type 2 GD is the rarest and most severe form. Traditionally, the presentation is considered stereotypic; however symptoms range from hydrops fetalis to the collodion baby phenotype to infants presenting after 6 months of life. Neurological involvement occurs early, resulting in severe degeneration with death in infancy or early childhood. However in the past decade, these infants have been living longer due to more aggressive interventions. The purpose of this study is to delineate the changing clinical course of type 2 GD. For this study we have identified a cohort of living and deceased patients with clinically and molecularly confirmed type 2 GD, We then conduct a structured telephone interview with parents of affected individuals. Medical issues address include disease presentation, disease progression, surgical history, medications, feeding issues, family history, management, complications, hospice care, cause of death and impact of disease on family members. Thus far, the review of 7 recent cases has shown a mean age at death of 26.5 months (ranging from 10 36 months). Four probands were treated with enzyme replacement therapy. All 7 patients received gastrostomy tubes while 3 underwent tracheostomies. Other interventions included treatment with Ambroxol and bone marrow transplantation. Current treatment options, while not curative, appear to be changing the clinical course of type 2 GD. Affected individuals are living longer, but interventions do not appear to markedly impact the neurological manifestations. This study has just begun and is anticipated to highlight newer complications and manifestations. Diagnosing and treating these infants has always been a challenge to clinicians. It is paramount to understand the baseline and any changes in the clinical course. This data is essential in the design of any future interventional protocols, helping identify treatment goals and milestones to determine efficacy.
doi:10.1016/j.ymgme.2016.11.300
292 Early intrathecal gene therapy extends lifespan and improves quality of life in a mouse model for infantile neuronal ceroid lipofuscinosis
S117
stage (4.5 months) extended lifespan by 4 months and delayed the onset of motor deficits by 3.5 months. IT-delivered scAAV9 vectors are currently used in two phase I clinical trials. Our preliminary findings, paired with the early onset and rapid decline in patients, and the already established route of delivery in humans, suggest this approach could be advanced as a treatment for INCL that is likely to provide the most benefit when administered early in the course of the disease. doi:10.1016/j.ymgme.2016.11.301
293 Expression of the lysosomal membrane protein LMBD1 is essential for the initiation of gastrulation Frank Rutscha, Petra Pennekampa, Yvonne Nitschkea, Chrishanthi Lowea, Boris Skryabinb, Insa Buersa, aMuenster University Children's Hospital, Muenster, Germany, bInstitute of Experimental Pathology, Muenster University, Muenster, Germany The rare inborn cblF defect of cobalamin metabolism is caused by mutations in the limb region 1 (LMBR1) domain containing 1 gene (LMBRD1). This defect is characterized by massive accumulation of free cobalamin in lysosomes and loss of mitochondrial succinyl-CoA synthesis and cytosolic methionine synthesis. Affected children suffer from heart defects, developmental delay and megaloblastic anemia. LMBRD1 encodes for LMBD1, a predicted lysosomal cobalamin transport protein. In this study, we determine the physiological function of LMBRD1 during embryogenesis by generating Lmbrd1 deficient mice using the Cre/loxP system. Complete loss of Lmbrd1 function is accompanied with early embryonic lethality in mice. Whole mount in situ hybridization studies against Bmp4 and Nodal show that initial formation of the proximal-distal axis is unaffected in early embryonic stages, whereas the initiation of gastrulation is disturbed shown by the expression pattern of Evx1 and Fgf8 in Lmbrd1 deficient mice. We conclude that intact function of LMBD1 is essential for the initiation of gastrulation. doi:10.1016/j.ymgme.2016.11.302
Alejandra J Rozenberg, Steven J Gray, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States Infantile neuronal ceroid lipofuscinosis (INCL) is a severe lysosomal disease caused by mutations in the CLN1 gene, which encodes the soluble lysosomal enzyme Palmitoyl-Protein-Thioesterase-1 (PPT1). In its absence, osmiophilic granules accumulate in lysosomes, eventually leading to neuroinflammation and neurodegeneration. Onset of symptoms occurs between 6 to 24 months, characterized by progressive visual failure, cognitive and motor decline, seizures and premature death. There is currently no cure, only palliative care. INCL mice recapitulate the major features of the disease; neurological deficits appear by 4.5 months with premature death around 8 months. A single intrathecal (IT) injection of self-complementary adeno-associated virus 9 (scAAV9) encoding the human CLN1 gene at an initial dose of 7x1010 vector genomes per mouse was administered via lumbar puncture to INCL mice at 1 week, 1 month (pre-symptomatic), 4.5 months (earlysymptomatic) or 6 months of age (symptomatic). While treatment at 4.5 months or later did not show therapeutic benefit, mice treated at 1 month survived approximately twice their expected lifespan. Mice treated at 1 week (modeling dosing soon after birth in humans) started showing motor deficits around 15 months and are currently alive, over 18 months of age. A 10-fold higher dose was subsequently tested. Lifespan was extended by 1.5 months in mice treated at the symptomatic stage (6 months). Treatment at the early-symptomatic
294 Structural basis of Hunter syndrome and construction of a database of mutant iduronate 2-sulfatase Hitoshi Sakurabaa, Seiji Saitob, Kazuki Ohnoc, aMeiji Pharmaceutical University, Kiyose, Japan, bHokkaido Information University, Ebetsu, Japan, cTokyo Institute of Technology, Tokyo, Japan Hunter syndrome (HS) is an X-linked genetic disorder caused by a deficiency of iduronate 2-sulfatase (IDS). Gross alterations of the IDS gene lead to the severe phenotype, but missense mutations comprising the majority of the mutations responsible for HS result in heterogeneous phenotypes ranging from the severe to the attenuated type. To elucidate the basis of HS from the structural viewpoint, we built a structural model of human IDS by means of the homology modeling and molecular dynamics methods. The results reveled that IDS consists of alpha/beta folds and the active site is located in the loop region near the N-terminal antiparallel beta-strand. Then we constructed structural models of mutant IDS proteins resulting from 134 missense mutations (phenotypes: 69 severe and 65 attenuated) for which the HS phenotypes have been clearly described, using the predicted wild-type IDS structure as a template. Then we analyzed the influence of each amino acid substitution on the IDS structure by