MPS Brazil Network: A summary of all mucopolysaccharidosis type IIIB patients

The MPS Brazil Network is a nonprofit organization founded in 2004 that aims to provide information, diagnosis and treatment monitoring and management of patients with mucopolysaccharidoses (MPS). MPS type IIIB is an autossomal recessive disorder caused by deficiency of alpha-N-acetylglycosaminidase leading to the accumulation of non-degraded or partially degraded heparan sulfate (HS). Due to this HS accumulation, patients present a wide spectrum of neurologic symptoms including hyperactivity, autistic features, progressive cognitive decline and dementia. We aimed to provide a profile of all of the MPS IIIB patients identified by the MPS Brazil Network within its 14 years of existence. Until now, the MPS Brazil Network has identified 1,460 MPS patients, of whom 130 (9%) present MPS IIIB. All patients were diagnosed by the identification of the specific enzyme deficiency. From the 130 patients, 62 (48%) were females and 68 (52% males). The average age at diagnosis was 6 years (range: 1-28 years of age). 29 patients were from other countries (Argentina 1, Ecuador 24, Nicaragua 1, Saudi Arabia 2 and Uruguay 10). The 101 Brazilian patients were found widespread in all country regions, with no disease clusters confirmed in Brazil so far. In conclusion, MPS IIIB is a relatively common MPS in Brazil, and efforts should be made to diagnose all cases and to identify them earlier in life, as new therapies for this condition (intra-cerebro-ventricular enzyme replacement therapy, gene therapy) are being developed and should become available in a near future.