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Factors affecting psychological adjustment in MPS I patients: an exploratory study and clinical observations
Abstracts
220 Mass spectrometry and thin layer chromatography analysis of brain gangliosides in Tay-Sachs disease mouse models Volkan Seyrantepea, Zehra Timura, C. Marschingb, Roger Sandhoff b, aIzmir Institute of Technology, Izmir, Turkey, bDeutches Krebsforschungzentrum (DKFZ), Heidelberg, Germany Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HEXA gene coding for α subunit of lysosomal βHexosaminidase A enzyme, which converts GM2 to GM3 ganglioside. HexA-/- mice, depleted of β-Hexosaminidase A enzyme, remains asymptomatic to 1 year of age, owing to the ability of these mice to catabolise stored GM2 ganglioside via sialidase(s) (Neu1, Neu2, Neu3 or Neu4) into glycolipid GA2 which further processed by βHexosaminidase B, thereby bypassing the HexA defect. Previously we showed that mice with targeted disruption of both HexA and Neu4 genes (HexA-/-Neu4-/-) have epileptic seizures and accumulating GM2 ganglioside in brain. To elucidate whether lysosomal sialidase Neu1 can also contribute to GM2 ganglioside degradation, we generated a triply mouse model by breeding HexA-/-Neu4-/mouse model and hypomorph mouse with reduced sialidase Neu1 activity. Thin layer chromatography and mass spectrometry analysis showed altered ganglioside profile in the brain of 6 months old triply (HexA-/-Neu4-/-Neu1-/-) mice. In particular, higher levels of GM2, GD1, GT1 and SM4s were detected in triply model than single (HexA-/-) and double (HexA-/-Neu1-/-) deficient model. Although GM1 level was lower in triply mice than single (HexA-/-) and double (HexA-/-Neu1-/-) deficient model, it was higher in single (Neu4-/-) and double (HexA-/-Neu4-/-) mice. Significantly higher level of GD2 was also detected in double (HexA-/-Neu1-/-) as well as triply (HexA-/-Neu4-/-Neu1-/-) mice indicating that sialidase Neu1 and Neu4 can also contribute ganglioside degradation in unknown metabolic pathway in Tay-Sachs disease mouse model.
doi:10.1016/j.ymgme.2013.12.232
221 Glycosylation and functionality of recombinant glucocerebrosidase from various production systems Yoseph Shaaltiel, Salit Tzaban, Mariana Hainrichson, Anna Gantman, David Aviezer, Yoram Tekoa, Protalix Biotherapeutics, Carmiel, Israel The glycosylation of recombinant β-glucocerebrosidase, the protein for enzyme replacement therapy of Gaucher disease, is shown to be a key factor for its functionality. Macrophages, the target cells for Gaucher disease internalize β-glucocerebrosidase through their mannose receptor. Three enzymes are available for treatment of Gaucher disease by enzyme replacement therapy (ERT). Taliglucerase, imiglucerase and velaglucerase are produced in different cell systems and over-go various post-translational or post-production glycosylation modifications to expose their mannose residues. For the first time, three enzyme glycosylation profiles were compared, using the same methodology. To understand the influence of the glycan pattern, we also measured functionality and uptake parameters of the three commercially available enzymes. Results show that the major differences in glycosylation profiles are in the variation of terminal residues and mannose chain length. The enzymatic activity and stability are not affected by these differences. Furthermore the cellular uptake and in-cell stability in rat and
S95
human macrophages are the same. Biodistribution studies showed that all b-glucocerebrosidase enzymes had a similar uptake trend, to the liver and spleen, the expected target organs. These results indicate that variations of glycosylation between the three available commercial β-glucocerebrosidase enzymes have no effect on their function or distribution.
doi:10.1016/j.ymgme.2013.12.233
222 Factors affecting psychological adjustment in MPS I patients: an exploratory study and clinical observations Elsa Shapiro, Kelly King, Kathleen Delaney, Alia Ahmed, Brianna Yund, Kyle Rudser, B. Whitley, University of Minnesota, Minneapolis, MN, USA Clinical observations in our MPS longitudinal study indicated developing psychological problems as MPS I patients with age. We observed that participants whose parents encouraged age-appropriate independent behavior did better, although not free of problems with low self-esteem and social withdrawal. We have previously reported that adaptive skills were low in all MPS I patients but equally or more impaired in Hurler Scheie (MPS IHS) than Hurler syndrome (MPS IH) patients. Hypotheses: Psychological problems 1) are more frequent in adolescents than younger children, 2) are influenced by diseaserelated and family expectation factors, and 3) are associated with poorer adaptive skills. Methods: 14 children with MPS IH and 13 with MPS IHS ages 6 to 18 were assessed. Parents completed the Behavior Assessment System for Children (BASC), Vineland Adaptive Behavior Scales, and a psychiatric/medical history interview from which a Physical Symptom Severity score (PSS) was calculated. All children had mutation analysis. Comparison of BASC scores were based on age and on disease severity and were correlated with adaptive skills (proxy for parent overprotection). Results: Among the MPS IH adolescents (over 12), 2/7 had a history of psychiatric problems/treatment, and in MPS IHS, 7/8, and among the younger children, 0/7 (MPS IH) compared to 1/5 (MPS IHS). Parent-rated BASC scores were similar for both groups with withdrawal and depression higher for the older patients. MPS IHS subgroup with the L238Q mutation have higher scores on depression and social withdrawal and all had treated psychiatric problems. Adaptive skills for all MPS I patients are below average; MPS IHS group had lower scores than those with MPS IH. A significant correlation of 0.6 was found between social withdrawal and adaptive function. Conclusion: While genetic factors contribute, parenting style and the social environment likely play an important role in promoting adaptive skills and may moderate psychological problems. The obstacles parents face, transition to adulthood, and contribution of parenting style and expectations for the child will be discussed. A significant need exists for better definition of the problem and for systematic research to determine appropriate interventions to promote better long-term outcomes. (Supported by the Lysosomal Disease Network NIH U54NS065768, Genzyme-Sanofi, National MPS Society, Ryan Foundation)
doi:10.1016/j.ymgme.2013.12.234
220 Mass spectrometry and thin layer chromatography analysis of brain gangliosides in Tay-Sachs disease mouse models Volkan Seyrantepea, Zehra Timura, C. Marschingb, Roger Sandhoff b, aIzmir Institute of Technology, Izmir, Turkey, bDeutches Krebsforschungzentrum (DKFZ), Heidelberg, Germany Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HEXA gene coding for α subunit of lysosomal βHexosaminidase A enzyme, which converts GM2 to GM3 ganglioside. HexA-/- mice, depleted of β-Hexosaminidase A enzyme, remains asymptomatic to 1 year of age, owing to the ability of these mice to catabolise stored GM2 ganglioside via sialidase(s) (Neu1, Neu2, Neu3 or Neu4) into glycolipid GA2 which further processed by βHexosaminidase B, thereby bypassing the HexA defect. Previously we showed that mice with targeted disruption of both HexA and Neu4 genes (HexA-/-Neu4-/-) have epileptic seizures and accumulating GM2 ganglioside in brain. To elucidate whether lysosomal sialidase Neu1 can also contribute to GM2 ganglioside degradation, we generated a triply mouse model by breeding HexA-/-Neu4-/mouse model and hypomorph mouse with reduced sialidase Neu1 activity. Thin layer chromatography and mass spectrometry analysis showed altered ganglioside profile in the brain of 6 months old triply (HexA-/-Neu4-/-Neu1-/-) mice. In particular, higher levels of GM2, GD1, GT1 and SM4s were detected in triply model than single (HexA-/-) and double (HexA-/-Neu1-/-) deficient model. Although GM1 level was lower in triply mice than single (HexA-/-) and double (HexA-/-Neu1-/-) deficient model, it was higher in single (Neu4-/-) and double (HexA-/-Neu4-/-) mice. Significantly higher level of GD2 was also detected in double (HexA-/-Neu1-/-) as well as triply (HexA-/-Neu4-/-Neu1-/-) mice indicating that sialidase Neu1 and Neu4 can also contribute ganglioside degradation in unknown metabolic pathway in Tay-Sachs disease mouse model.
doi:10.1016/j.ymgme.2013.12.232
221 Glycosylation and functionality of recombinant glucocerebrosidase from various production systems Yoseph Shaaltiel, Salit Tzaban, Mariana Hainrichson, Anna Gantman, David Aviezer, Yoram Tekoa, Protalix Biotherapeutics, Carmiel, Israel The glycosylation of recombinant β-glucocerebrosidase, the protein for enzyme replacement therapy of Gaucher disease, is shown to be a key factor for its functionality. Macrophages, the target cells for Gaucher disease internalize β-glucocerebrosidase through their mannose receptor. Three enzymes are available for treatment of Gaucher disease by enzyme replacement therapy (ERT). Taliglucerase, imiglucerase and velaglucerase are produced in different cell systems and over-go various post-translational or post-production glycosylation modifications to expose their mannose residues. For the first time, three enzyme glycosylation profiles were compared, using the same methodology. To understand the influence of the glycan pattern, we also measured functionality and uptake parameters of the three commercially available enzymes. Results show that the major differences in glycosylation profiles are in the variation of terminal residues and mannose chain length. The enzymatic activity and stability are not affected by these differences. Furthermore the cellular uptake and in-cell stability in rat and
S95
human macrophages are the same. Biodistribution studies showed that all b-glucocerebrosidase enzymes had a similar uptake trend, to the liver and spleen, the expected target organs. These results indicate that variations of glycosylation between the three available commercial β-glucocerebrosidase enzymes have no effect on their function or distribution.
doi:10.1016/j.ymgme.2013.12.233
222 Factors affecting psychological adjustment in MPS I patients: an exploratory study and clinical observations Elsa Shapiro, Kelly King, Kathleen Delaney, Alia Ahmed, Brianna Yund, Kyle Rudser, B. Whitley, University of Minnesota, Minneapolis, MN, USA Clinical observations in our MPS longitudinal study indicated developing psychological problems as MPS I patients with age. We observed that participants whose parents encouraged age-appropriate independent behavior did better, although not free of problems with low self-esteem and social withdrawal. We have previously reported that adaptive skills were low in all MPS I patients but equally or more impaired in Hurler Scheie (MPS IHS) than Hurler syndrome (MPS IH) patients. Hypotheses: Psychological problems 1) are more frequent in adolescents than younger children, 2) are influenced by diseaserelated and family expectation factors, and 3) are associated with poorer adaptive skills. Methods: 14 children with MPS IH and 13 with MPS IHS ages 6 to 18 were assessed. Parents completed the Behavior Assessment System for Children (BASC), Vineland Adaptive Behavior Scales, and a psychiatric/medical history interview from which a Physical Symptom Severity score (PSS) was calculated. All children had mutation analysis. Comparison of BASC scores were based on age and on disease severity and were correlated with adaptive skills (proxy for parent overprotection). Results: Among the MPS IH adolescents (over 12), 2/7 had a history of psychiatric problems/treatment, and in MPS IHS, 7/8, and among the younger children, 0/7 (MPS IH) compared to 1/5 (MPS IHS). Parent-rated BASC scores were similar for both groups with withdrawal and depression higher for the older patients. MPS IHS subgroup with the L238Q mutation have higher scores on depression and social withdrawal and all had treated psychiatric problems. Adaptive skills for all MPS I patients are below average; MPS IHS group had lower scores than those with MPS IH. A significant correlation of 0.6 was found between social withdrawal and adaptive function. Conclusion: While genetic factors contribute, parenting style and the social environment likely play an important role in promoting adaptive skills and may moderate psychological problems. The obstacles parents face, transition to adulthood, and contribution of parenting style and expectations for the child will be discussed. A significant need exists for better definition of the problem and for systematic research to determine appropriate interventions to promote better long-term outcomes. (Supported by the Lysosomal Disease Network NIH U54NS065768, Genzyme-Sanofi, National MPS Society, Ryan Foundation)
doi:10.1016/j.ymgme.2013.12.234