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Epidemiology of mucopolysaccharidoses (MPS) in the United States: challenges and opportunities
Abstracts / Molecular Genetics and Metabolism 120 (2016) S17–S145
Hurler syndrome (mucopolysaccharidosis type I, MPS I) is an autosomal recessive lysosomal disorder that arises due to deficiency of lysosomal hydrolase α-L-iduronidase (IDUA). The result of defects in this enzyme is the accumulation of glycosaminoglycans (GAG) heparan and dermatan sulfate. In addition to this primary substrate accumulation, increased levels of gangliosides GM2 and GM3 has been observed by histochemical methods and by densitometry of fractions separated by high performance and thin layer chromatography. These methods, however, lack the sensitivity to accurately quantitate ganglioside content from tissues of affected and normal animal tissues. We hypothesize that high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) might provide an improved method of ganglioside quantification suitable for murine and clinical purposes. For this study, 6-7 month old MPS I (n =7) and heterozygous (n =7) animals were evaluated. Brain tissue was dissected into 3 regions: hippocampus, cerebellum, and cortex. Specimens were processed and run through an HPLC system coupled to a triple quadrupole mass spectrometer, operated in negative MRM mode. Output was processed and reported as the peak area ratios of the analytes to the corresponding internal standard. In the cerebellum of MPS I mice, the peak area ratio for ganglioside species GM2(16:0), GM2(18:0), GM2(20:0), GM3(16:0), GM3(18:0), and GM3(20:0) were 52%, 156%, 107%, 32%, 88%, and 164% higher than normal heterozygote control animals, respectively. In the hippocampus, the respective ganglioside species were significantly increased 145%, 268%, 229%, 44%, 130%, and 158% compared to controls. Similarly, the ganglioside species GM2(18:0), GM2(20:0), GM3(18:0), and GM3(20:0) were increased in the cortex by 369%, 251%, 262%, and 316%, respectively. By utilizing HPLC-MS/MS, it has been possible to discriminate between, and accurately quantify, the abundance of multiple ganglioside species in brain tissue of MPS I and normal heterozygous mice. (Supported by NIH grant “Gene Therapy for Metabolic Diseases” 5P01HD032652.)
doi:10.1016/j.ymgme.2016.11.283
275 Combined deficiencies of endosomal ganglioside neuraminidases 3 and 4 in mice cause lysosomal GM3 gangliosidosis Alexey Pshezhetskya, Xuefang Pana, Camila De Britto Pará De Aragãoa, Juan Velasco-Martinb, David Priestmanc, Frances Plattc, Nathalie Lamarche-Vaned, Carlos Moralesd, Taeko Miyagie, aCHU Ste-Justine, University of Montreal, Montreal, QC, Canada, bUniversidad c Autónoma de Madrid, Madrid, Spain, University of Oxford, Oxford, d United Kingdom, McGill University, Montreal, QC, Canada, eTohoku Pharmacological University, Sendai, Japan The sialylated glycosphingolipids gangliosides are essential to myelination, axon integrity, transmission of nervous impulses and memory consolidation. Ganglioside expression patterns in the brain are cell-specific, dynamic and maintained by highly coordinated processes of biosynthesis, trafficking, processing and catabolism. The changes in the composition of gangliosides during development and aging cannot be explained based solely on the regulation of the ganglioside-synthesizing enzymes, sialyltransferases, suggesting that neuraminidases play essential role. Two brain glycolipid neuraminidases, Neu3 and Neu4 residing in lysosomal and plasma membranes are major candidates for processing brain gangliosides, but the corresponding knockout mouse models showed no changes in brain ganglioside metabolism or deficits in brain function. To elucidate the physiological functions of Neu4 and Neu3 in the brain, we generated a mouse strain (neu3-/-;neu4-/-) devoid of both enzymes. With age
S111
the mice showed progressive deficits in spatial and short-term memory. Neuraminidase activity against gangliosides in the brain tissues of neu3-/-;neu4-/- mice was below detection levels. GM3 ganglioside accumulated in lysosomes of microglia and pericytes and GM1 ganglioside was decreased in neurons. Cultured hippocampal and cortical neurons showed reduced levels of GM1 in growing axons and impaired neuritogenesis. Pathological examination revealed accumulation of lysosomal storage bodies in neurons in the deep cortical layers and in the vast majority of microglia and vascular pericytes. The number of astrocytes and activated microglia was increased, consistent with neuroinflammation. Together our data demonstrate that ganglioside composition is modulated by the interplay of sialyltransferases and neuraminidases: the sialyltransferases generate essential (mainly complex) gangliosides in early Golgi, while neuraminidases produce gangliosides at the required time/site by “trimming” sialic residues. Neu3 and Neu4 have unique roles essential for CNS function: Neu4 induces axon growth by generating the neuronal GM1 whereas Neu3 catabolizes GM3 in brain phagocytic cells preventing its storage in lipofuscin bodies.
doi:10.1016/j.ymgme.2016.11.284
276 Epidemiology of mucopolysaccharidoses (MPS) in the United States: challenges and opportunities Yana Pucketta, Eileen Buib, Alan Zelicoffc, Adriana Montanob, aTexas Tech University Health Sciences Center, Lubbock, TX, United States, b Saint Louis University School of Medicine, St. Louis, MO, United States, c Saint Louis University School of Public Health and Social Justice, St. Louis, MO, United States Introduction: Previous studies on incidence and prevalence of mucopolysaccharidoses (MPS) show considerable variation and are mainly originated in countries other than United States (U.S.). This study aimed to identify the incidence and prevalence of MPS in the U.S. Materials and Methods: A retrospective epidemiological review was performed utilizing the database from the National MPS Society between 1995-2005. Data included year of birth, geographic location of MPS patient, year of death, and MPS variant type. Population information was obtained from the National U.S. Census Bureau. The incidence and prevalence rates were calculated for each disease. Incidence rates were calculated for each state. Results: Incidence and prevalence of MPS in the U.S. was found to be 1.2 per 100,000 live births and 1.8 per 1 million respectively. MPS I had the highest incidence and prevalence of .34/100,000 and .50/1,000,000. The birth incidences of MPS II, III, IV, VI, and VII were .29, .38, .09, .05, and .05 per 100,000 live births, respectively. Conclusion: To date, this is the most comprehensive review of the incidence and prevalence of all MPS in the U.S. Wide disparities are observed in incidence rates by location in U.S.
doi:10.1016/j.ymgme.2016.11.285
277 Olipudase alfa for the treatment of acid sphingomyelinase deficiency (ASMD): safety and efficacy in adults treated for 30 months Ana Cristina Pugaa, Melissa Wassersteinb, George Diazc, Robin Lachmannd, Marie-Helene Jouvina, Indrani Nandya, Allena Jia, Haig Inguliziana,
Hurler syndrome (mucopolysaccharidosis type I, MPS I) is an autosomal recessive lysosomal disorder that arises due to deficiency of lysosomal hydrolase α-L-iduronidase (IDUA). The result of defects in this enzyme is the accumulation of glycosaminoglycans (GAG) heparan and dermatan sulfate. In addition to this primary substrate accumulation, increased levels of gangliosides GM2 and GM3 has been observed by histochemical methods and by densitometry of fractions separated by high performance and thin layer chromatography. These methods, however, lack the sensitivity to accurately quantitate ganglioside content from tissues of affected and normal animal tissues. We hypothesize that high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) might provide an improved method of ganglioside quantification suitable for murine and clinical purposes. For this study, 6-7 month old MPS I (n =7) and heterozygous (n =7) animals were evaluated. Brain tissue was dissected into 3 regions: hippocampus, cerebellum, and cortex. Specimens were processed and run through an HPLC system coupled to a triple quadrupole mass spectrometer, operated in negative MRM mode. Output was processed and reported as the peak area ratios of the analytes to the corresponding internal standard. In the cerebellum of MPS I mice, the peak area ratio for ganglioside species GM2(16:0), GM2(18:0), GM2(20:0), GM3(16:0), GM3(18:0), and GM3(20:0) were 52%, 156%, 107%, 32%, 88%, and 164% higher than normal heterozygote control animals, respectively. In the hippocampus, the respective ganglioside species were significantly increased 145%, 268%, 229%, 44%, 130%, and 158% compared to controls. Similarly, the ganglioside species GM2(18:0), GM2(20:0), GM3(18:0), and GM3(20:0) were increased in the cortex by 369%, 251%, 262%, and 316%, respectively. By utilizing HPLC-MS/MS, it has been possible to discriminate between, and accurately quantify, the abundance of multiple ganglioside species in brain tissue of MPS I and normal heterozygous mice. (Supported by NIH grant “Gene Therapy for Metabolic Diseases” 5P01HD032652.)
doi:10.1016/j.ymgme.2016.11.283
275 Combined deficiencies of endosomal ganglioside neuraminidases 3 and 4 in mice cause lysosomal GM3 gangliosidosis Alexey Pshezhetskya, Xuefang Pana, Camila De Britto Pará De Aragãoa, Juan Velasco-Martinb, David Priestmanc, Frances Plattc, Nathalie Lamarche-Vaned, Carlos Moralesd, Taeko Miyagie, aCHU Ste-Justine, University of Montreal, Montreal, QC, Canada, bUniversidad c Autónoma de Madrid, Madrid, Spain, University of Oxford, Oxford, d United Kingdom, McGill University, Montreal, QC, Canada, eTohoku Pharmacological University, Sendai, Japan The sialylated glycosphingolipids gangliosides are essential to myelination, axon integrity, transmission of nervous impulses and memory consolidation. Ganglioside expression patterns in the brain are cell-specific, dynamic and maintained by highly coordinated processes of biosynthesis, trafficking, processing and catabolism. The changes in the composition of gangliosides during development and aging cannot be explained based solely on the regulation of the ganglioside-synthesizing enzymes, sialyltransferases, suggesting that neuraminidases play essential role. Two brain glycolipid neuraminidases, Neu3 and Neu4 residing in lysosomal and plasma membranes are major candidates for processing brain gangliosides, but the corresponding knockout mouse models showed no changes in brain ganglioside metabolism or deficits in brain function. To elucidate the physiological functions of Neu4 and Neu3 in the brain, we generated a mouse strain (neu3-/-;neu4-/-) devoid of both enzymes. With age
S111
the mice showed progressive deficits in spatial and short-term memory. Neuraminidase activity against gangliosides in the brain tissues of neu3-/-;neu4-/- mice was below detection levels. GM3 ganglioside accumulated in lysosomes of microglia and pericytes and GM1 ganglioside was decreased in neurons. Cultured hippocampal and cortical neurons showed reduced levels of GM1 in growing axons and impaired neuritogenesis. Pathological examination revealed accumulation of lysosomal storage bodies in neurons in the deep cortical layers and in the vast majority of microglia and vascular pericytes. The number of astrocytes and activated microglia was increased, consistent with neuroinflammation. Together our data demonstrate that ganglioside composition is modulated by the interplay of sialyltransferases and neuraminidases: the sialyltransferases generate essential (mainly complex) gangliosides in early Golgi, while neuraminidases produce gangliosides at the required time/site by “trimming” sialic residues. Neu3 and Neu4 have unique roles essential for CNS function: Neu4 induces axon growth by generating the neuronal GM1 whereas Neu3 catabolizes GM3 in brain phagocytic cells preventing its storage in lipofuscin bodies.
doi:10.1016/j.ymgme.2016.11.284
276 Epidemiology of mucopolysaccharidoses (MPS) in the United States: challenges and opportunities Yana Pucketta, Eileen Buib, Alan Zelicoffc, Adriana Montanob, aTexas Tech University Health Sciences Center, Lubbock, TX, United States, b Saint Louis University School of Medicine, St. Louis, MO, United States, c Saint Louis University School of Public Health and Social Justice, St. Louis, MO, United States Introduction: Previous studies on incidence and prevalence of mucopolysaccharidoses (MPS) show considerable variation and are mainly originated in countries other than United States (U.S.). This study aimed to identify the incidence and prevalence of MPS in the U.S. Materials and Methods: A retrospective epidemiological review was performed utilizing the database from the National MPS Society between 1995-2005. Data included year of birth, geographic location of MPS patient, year of death, and MPS variant type. Population information was obtained from the National U.S. Census Bureau. The incidence and prevalence rates were calculated for each disease. Incidence rates were calculated for each state. Results: Incidence and prevalence of MPS in the U.S. was found to be 1.2 per 100,000 live births and 1.8 per 1 million respectively. MPS I had the highest incidence and prevalence of .34/100,000 and .50/1,000,000. The birth incidences of MPS II, III, IV, VI, and VII were .29, .38, .09, .05, and .05 per 100,000 live births, respectively. Conclusion: To date, this is the most comprehensive review of the incidence and prevalence of all MPS in the U.S. Wide disparities are observed in incidence rates by location in U.S.
doi:10.1016/j.ymgme.2016.11.285
277 Olipudase alfa for the treatment of acid sphingomyelinase deficiency (ASMD): safety and efficacy in adults treated for 30 months Ana Cristina Pugaa, Melissa Wassersteinb, George Diazc, Robin Lachmannd, Marie-Helene Jouvina, Indrani Nandya, Allena Jia, Haig Inguliziana,