Background: Mucopolysaccharidosis type III (MPS III) is the type of mucopolysaccharidosis that
has fewer systemic signs and symptoms, however, it has the most severe neurological
impairment. There are four types of MPS III, determined by the mutation in the gene
responsible for the enzyme that becomes deficient in degrading intracellular glycosaminoglycan,
which is responsible for the clinical picture.
Objective: Describe the cases of MPS III at a Reference Center for Rare Diseases in Ceará.
Methods: Quantitative, cross-sectional, retrospective, observational study of MPS III cases
from 2000 to 2022 at the Reference Center for Rare Diseases of Ceará. The variables
were: type of MPS, sex, age at study, age of onset, age at diagnosis, neurological
developmental milestones, neurological signs/symptoms, neuroimaging data, and death
(yes/no).
Results: We evaluated 12 cases, 6 MPS IIIB, 4 MPS IIIA, and 2 MPS IIIC. Five were female.
Three had consanguinity, four had a familial recurrence. The first symptoms occurred
between 1 month and 3 years of age and the speech-language disorders were more frequent.
The etiological diagnosis was performed between 2-18 years. In all cases, there was
a delay in neurodevelopmental milestones. In the clinical picture, the presence of
seizures, behavior disorder, intellectual disability, hyperactivity, autism, hydrocephalus,
and dysphagia are highlighted. There were three cases of abandonment of follow-up
and four deaths, three due to respiratory failure and one due to sepsis in the age
group of 13 to 19 years.
Conclusions: Severe neurological impairment is evident in all cases of MPS III. Strategies must
be implemented to avoid delay in diagnosis, such as happened in the cases presented,
including to enable future treatment with gene therapy, possible only for asymptomatic
cases or with initial symptoms.
