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Brain magnetic resonance imaging findings in patients with mucopolysaccharidosis VI
Ana C M Azevedo1, Osvaldo Artigalás, Leonardo Vedolin
1Medical Genetics Service, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil.
Introduction:
Mucopolysaccharidosis type VI (MPS VI) is a rare lysosomal storage disorder caused by the deficient activity of N-acetylgalactosamine 4-sulfatase. MPS VI is usually considered as not being associated with mental retardation.
Aims/Methods:
The main objective of the present study was to describe brain magnetic resonance imaging (MRI) findings and their correlation with clinical and biochemical findings in MPS VI patients. The study was conducted at Hospital de Clínicas de Porto Alegre, Brazil with 25 MPS VI patients. All patients were evaluated through clinical evaluation, IQ tests, urinary glycosaminoglycans (GAG) analysis, and brain MRI.
Results:
Mean age at evaluation was 10.6 ± 4.52 years. Five of 16 patients presented total IQ below the normal range. Brain MRI was abnormal in the majority of patients (n = 19/21), and the most frequent abnormalities found were the presence of dilated perivascular spaces and white matter lesions. Correlations were found between age and normalized white matter lesion load (NLL) (r = 0.46; p = 0.04) and normalized cerebral volume (NCV) (r = -0.56; p = 0.01), between NLL and height deficit (r = 0.48; p = 0.04), and between NCV and weight deficit (r = -0.58; p = 0.01) and height deficit (r = -0.55; p = 0.01). A correlation between urinary GAG levels and quantitative brain MRI findings was not found, neither between qualitative and quantitative brain MRI findings and IQ scores.
Conclusions:
MPS VI patients may present abnormal IQ scores without correlation with brain abnormalities on the MRI, a finding which was found to be very frequent in MPS VI. Additional studies are required to confirm our findings.
Insights
Mucopolysaccharidosis type VI (MPS VI) patients frequently show brain MRI abnormalities, including dilated perivascular spaces and white matter lesions. These brain changes in MPS VI do not correlate with IQ scores, despite some patients having below-normal IQ.
Area of Science:
- Neurology
- Genetics
- Biochemistry
Background:
- Mucopolysaccharidosis type VI (MPS VI) is a rare lysosomal storage disorder resulting from deficient N-acetylgalactosamine 4-sulfatase activity.
- MPS VI is typically not associated with intellectual disability.
Purpose of the Study:
- To investigate brain magnetic resonance imaging (MRI) findings in patients with MPS VI.
- To correlate these MRI findings with clinical and biochemical data, including IQ scores.
Main Methods:
- The study included 25 MPS VI patients evaluated through clinical assessment, IQ testing, urinary glycosaminoglycans (GAG) analysis, and brain MRI.
- Statistical analyses were performed to identify correlations between various parameters.
Main Results:
- The majority of patients (19/21) exhibited abnormal brain MRI findings, most commonly dilated perivascular spaces and white matter lesions.
- Significant correlations were observed between age and white matter lesion load, and between normalized cerebral volume and deficits in height and weight.
- No correlation was found between urinary GAG levels and brain MRI findings, nor between MRI findings and IQ scores.
Conclusions:
- Brain MRI abnormalities are frequent in MPS VI patients.
- Abnormal IQ scores can occur in MPS VI patients independently of observed brain MRI changes.
- Further research is needed to validate these findings and understand the underlying mechanisms.
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