title: Mucopolysaccharidoses in northern Brazil: Targeted mutation screening and urinary glycosaminoglycan excretion in patients undergoing enzyme replacement therapy.
abstract: Mucopolysaccharidoses (MPS) are rare lysosomal disorders caused by the deficiency of specific lysosomal enzymes responsible for glycosaminoglycan (GAG) degradation. Enzyme Replacement Therapy (ERT) has been shown to reduce accumulation and urinary excretion of GAG, and to improve some of the patients' clinical signs. We studied biochemical and molecular characteristics of nine MPS patients (two MPS I, four MPS II and three MPS VI) undergoing ERT in northern Brazil. The responsiveness of ERT was evaluated through urinary GAG excretion measurements. Patients were screened for eight common MPS mutations, using PCR, restriction enzyme tests and direct sequencing. Two MPS I patients had the previously reported mutation p.P533R. In the MPS II patients, mutation analysis identified the mutation p.R468W, and in the MPS VI patients, polymorphisms p.V358M and p.V376M were also found. After 48 weeks of ERT, biochemical analysis showed a significantly decreased total urinary GAG excretion in patients with MPS I (p < 0.01) and MPS VI (p < 0.01). Our findings demonstrate the effect of ERT on urinary GAG excretion and suggest the adoption of a screening strategy for genotyping MPS patients living far from the main reference centers.
authors.affiliation: Laboratório de Erros Inatos do Metabolismo, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil.
authors.forename: Gustavo M
authors.initials: GM
authors.lastname: Viana
authors.forename: Nathália O
authors.initials: NO
authors.lastname: de Lima
authors.forename: Rosely
authors.initials: R
authors.lastname: Cavaleiro
authors.forename: Erik
authors.initials: E
authors.lastname: Alves
authors.forename: Isabel C N
authors.initials: IC
authors.lastname: Souza
authors.forename: Raimunda
authors.initials: R
authors.lastname: Feio
authors.forename: Sandra
authors.initials: S
authors.lastname: Leistner-Segal
authors.forename: Ida
authors.initials: I
authors.lastname: Schwartz
authors.forename: Roberto
authors.initials: R
authors.lastname: Giugliani
authors.forename: Luiz C Santana
authors.initials: LC
authors.lastname: da Silva