A novel missense mutation in lysosomal sulfamidase is the basis of MPS III A in a spontaneous mouse mutant. (9/99)

Sanfilippo syndrome type III A (Mucopolysaccharidosis (MPS) III A) is a rare, autosomal recessive, lysosomal storage disease, characterized by the accumulation of heparan sulfate and the loss of function of lysosomal heparan N-sulfatase activity. The disease leads to devastating mental and physical consequences and a mouse model that can be used to explore gene therapy and enzyme or cell replacement therapies is needed. We have previously identified a mouse with low sulfamidase activity and symptoms and pathologies typical of MPS III A (Bhaumik, M., Muller, V. J., Rozaklis, T., Johnson, L., Dobrenis, K., Bhattacharyya, R., Wurzelmann, S., Finamore, P., Hopwood, J. J., Walkley, S. U., and Stanley, P. [1999] A mouse model for mucopolysaccharidosis type III A (Sanfilippo syndrome). Glycobiology 9, 1389--1396). We now show that the sulfamidase gene of the MPS III A mouse carries a novel mutation (G91A) that gives an amino acid change (D31N) likely to interfere with the coordination of a divalent metal ion in the active site of this sulfatase. This spontaneous mouse mutant is an excellent model for MPS III A in humans as this disease often arises due to a missense mutation in lysosomal sulfamidase.  (+info)

Neurological correction of lysosomal storage in a mucopolysaccharidosis IIIB mouse model by adeno-associated virus-mediated gene delivery. (10/99)

Mucopolysaccharidosis (MPS) IIIB is characterized by mild somatic features and severe neurological diseases leading to premature death. No definite treatment is available for MPS IIIB patients. We constructed two recombinant adeno-associated virus (rAAV) vectors containing the human alpha-N-acetylglucosaminidase (NaGlu) cDNA driven by either a CMV or a neuron-specific enolase (NSE) promoter. In vitro, these rAAV vectors mediated efficient expression of recombinant NaGlu in human MPS IIIB fibroblasts and mouse MPS IIIB somatic and brain primary cell cultures. The secreted rNaGlu was taken up by both human and mouse MPS IIIB cells in culture and degraded the accumulated glycosaminoglycans (GAG). A direct microinjection (10(7) viral particles, 1 microl/10 minutes per injection) of vectors containing the NSE promoter resulted in long-term (6 months, the duration of the experiments) expression of rNaGlu in multiple brain structures/areas of adult MPS IIIB mice. Consistent with previous studies, the main target cells were neurons. However, while vector typically transduced an area of 400-500 microm surrounding the infusion sites, the correction of GAG storage involved neurons of a much broader area (1.5 mm) in a 6-month duration of experiments. These results provide a basis for the development of a treatment for neurological disease in MPS IIIB patients using AAV vectors.  (+info)

Genetic complementation studies of multiple sulfatase deficiency. (11/99)

Cultured fibroblasts from two individuals with multiple sulfatase deficiency (MSD) were found to have decreased activities of arylsulfatases (aryl-sulfate sulfohydrolase, EC 3.1.6.1) A, B, and C as well as iduronate-sulfate sulfatase, sulfamidase, and N-acetylglucosamine-6-sulfate sulfatase. The activity of N-acetylgalactosamine-6-sulfate sulfatase was decreased in one line but not in the other. Mixtures of MSD cell extracts with extracts from normal cells did not result in inhibition of normal sulfatase activities. Mixtures of MSD cell extracts with extracts of fibroblasts from patients with Hunter or Sanfilippo A syndrome did not activate iduronate-sulfate sulfatase or sulfamidase activity. Heterokaryons formed by fusion of MSD cells with Sanfilippo A fibroblasts demonstrated a partial correction of the enzyme deficiency. In similar manner, MSD-Hunter heterokaryons showed a significant increase in iduronate-sulfate-sulfatase activity. Genetic complementation in heterokaryons of MSD fibroblasts and cells of either Sanfilippo A or Hunter syndrome implies a genetic defect in MSD different from that causing specific sulfatase deficiencies.  (+info)

Correction of mucopolysaccharidosis type IIIb fibroblasts by lentiviral vector-mediated gene transfer. (12/99)

Mucopolysaccharidosis type IIIB (MPS IIIB; or Sanfilippo syndrome type B) is a lysosomal disease, due to glycosaminoglycan storage caused by mutations on the alpha-N-acetylglucosaminidase (NAGLU) gene. The disease is characterized by neurological dysfunction but relatively mild somatic manifestations. No effective treatment is available for affected patients. In the present study, we evaluated the role of a lentiviral vector as the transducing agent of NAGLU cDNA in MPS IIIB fibroblasts. The vector expressed high transduction efficiency and high levels of enzymic activity, 20-fold above normal levels, persisting for at least 2 months. PCR experiments confirmed the integration of the viral vector into the target genome. The NAGLU activity restored by virus infection was sufficient to normalize glycosaminoglycan accumulation, which is directly responsible for the disease phenotype. Metabolic labelling experiments on transduced fibroblasts exhibited, in the medium and in cellular lysates, polypeptide forms of 84 and 80 kDa respectively related to the precursor and mature forms of the enzyme. The enzyme secreted by transduced MPS IIIB fibroblasts was endocytosed in deficient cells by the mannose 6-phosphate system. Thus we show that lentiviral vectors may provide a therapeutic approach for the treatment of MPS IIIB disease.  (+info)

Activated microglia in cortex of mouse models of mucopolysaccharidoses I and IIIB. (13/99)

Alpha-N-acetylglucosaminidase deficiency (mucopolysaccharidosis IIIB, MPS IIIB) and alpha-l-iduronidase deficiency (MPS I) are heritable lysosomal storage diseases; neurodegeneration is prominent in MPS IIIB and in severe cases of MPS I. We have obtained morphologic and molecular evidence for the involvement of microglia in brain pathology of mouse models of the two diseases. In the cortex, a subset of microglia (sometimes perineuronal) consists of cells that are probably phagocytic; they have large storage vacuoles, react with MOMA-2 (monoclonal antibody against macrophages) and Griffonia simplicifolia isolectin IB(4), and stain intensely for the lysosomal proteins Lamp-1, Lamp-2, and cathepsin D as well as for G(M3) ganglioside. MOMA-2-positive cells appear at 1 and 6 months in MPS IIIB and MPS I mice, respectively, but though their number increases with age, they remain sparse. However, a profusion of cells carrying the macrophage CD68/macrosialin antigen appear in the cortex of both mouse models at 1 month. mRNA encoding CD68/macrosialin also increases at that time, as shown by microarray and Northern blot analyses. Ten other transcripts elevated in both mouse models are associated with macrophage functions, including complement C4, the three subunits of complement C1q, lysozyme M, cathepsins S and Z, cytochrome b558 small subunit, macrophage-specific protein 1, and DAP12. An increase in IFN-gamma and IFN-gamma receptor was observed by immunohistochemistry. These functional increases may represent activation of resident microglia, an influx and activation of blood monocytes, or both. They show an inflammatory component of brain disease in the two MPS, as is known for many neurodegenerative disorders.  (+info)

Sanfilippo syndrome type D: identification of the first mutation in the N-acetylglucosamine-6-sulphatase gene. (14/99)

Mucopolysaccharidosis type IIID is the least common of the four subtypes of Sanfilippo syndrome. It is caused by a deficiency of N-acetylglucosamine-6-sulphatase, which is one of the enzymes involved in the catabolism of heparan sulphate. We present the clinical, biochemical, and, for the first time, the molecular diagnosis of a patient with Sanfilippo D disease. The patient was found to be homozygous for a single base pair deletion (c1169delA), which will cause a frameshift and premature termination of the protein. Accurate carrier detection is now available for other members of this consanguineous family.  (+info)

Anaestethic problems in Sanfilippo syndrome. A rare case of adult patient. (15/99)

The authors report the case of a female patient (41 years old) affected by mucopolysaccharidosis type III or Sanfilippo syndrome submitted to a gynecologic surgical procedure and describe the main anesthesiologic problems. A sub-arachnoid anesthesia with hyperbaric Bupivacain 0.5% was used. This technique proved to be safe and convenient without peri- and postoperative complications.  (+info)

Secondary skeletal involvement in Sanfilippo syndrome. (16/99)

BACKGROUND: Sanfilippo syndrome, or mucopolysaccharidosis (MPS) type III, is a rare lysosomal storage disease, resulting from errors in the catabolism of heparan sulphate. AIM: To evaluate bone turnover and bone mineral density (BMD) in MPS type III patients. DESIGN: Clinical and observational study. METHODS: We evaluated serum markers of bone formation or resorption, and measured BMD using dual-energy X-ray absorptiometry (DEXA), in three patients with MPS type III. RESULTS: Serum vitamin D were low, and BMDs greatly reduced at lumbar and femoral sites, indicating the possibility of osteoporosis and osteomalacia. DISCUSSION: These skeletal effects probably result from nutritional deficiencies and inability to walk, rather than from the genetic defect itself. Secondary skeletal involvement in patients with MPS type III may represent a considerable cause of morbidity, and requires interventions to reduce the risk of pathological fractures.  (+info)