Brain magnetic resonance imaging findings in patients with mucopolysaccharidosis VI.

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.

Mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome): assessment of joint mobility and grip and pinch strength.

OBJECTIVE: To describe the profile of joint mobility and grip and pinch strength of MPS VI patients and to correlate this with urinary excretion of glycosaminoglycans (GAGs), ARSB activity, and the distance covered in a 6-minute walking test (6MWT). METHODS: This was an observational study of 28 patients with MPS VI, who had not undergone specific treatment. All patients were assessed for amplitude of joint mobility (shoulder, elbow, and knee), grip and pinch strength and urinary GAG excretion and also performed the 6MWT. RESULTS: Shoulder flexion exhibited the greatest limitation, with no correlation with age, followed by knee extension and elbow flexion, both of which were correlated inversely with age. Hand grip strength was compromised in all patients, and pinch strength exhibited a positive correlation with age. CONCLUSIONS: The fact that restricted shoulder flexion was not correlated with age suggests that this finding is present early on in MPS VI and that it constitutes an important clinical sign that should arouse diagnostic suspicion of this disease. The amplitude of knee extension and elbow flexion, in turn, are possible markers of disease progression since they have a negative correlation with age. Further studies are needed to confirm these hypotheses.

Mucopolissacaridose tipo VI (síndrome de Maroteaux-Lamy): avaliação da mobilidade articular e das forças de garra e de pinça / Mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome): assessment of joint mobility and grip and pinch strength

OBJETIVO: Descrever o perfil de mobilidade articular e das forças de garra e de pinça de indivíduos com MPS VI, além de sua correlação com a excreção urinária de glicosaminoglicanos, atividade da ARSB e distância percorrida no teste de caminhada de 6 minutos. MÉTODOS: Estudo observacional de 28 pacientes com MPS VI, não submetidos a tratamento específico. Todos os pacientes foram avaliados em relação à amplitude da mobilidade articular, forças de garra e de pinça, excreção urinária de glicosaminoglicanos, atividade da ARSB e teste de caminhada de 6 minutos. RESULTADOS: Demonstrou-se maior comprometimento de flexão de ombro, sem correlação com a idade, e da extensão de joelho e flexão de cotovelo, estas últimas correlacionadas negativamente com a idade. A força de garra mostrou-se comprometida em todos os pacientes, e a força de pinça apresentou correlação positiva com idade. CONCLUSÕES: A restrição da flexão de ombro, sem correlação com a idade, sugere que este achado esteja presente precocemente na MPS VI e se constitua em sinal clínico importante para suspeita diagnóstica desta doença. A amplitude da extensão de joelho e da flexão de cotovelo, por sua vez, por apresentarem correlação negativa com a idade, são possíveis marcadores da evolução da doença. Estudos adicionais são necessários para confirmação dessas hipóteses.

OBJECTIVE: To describe the profile of joint mobility and grip and pinch strength of MPS VI patients and to correlate this with urinary excretion of glycosaminoglycans (GAGs), ARSB activity, and the distance covered in a 6-minute walking test (6MWT). METHODS: This was an observational study of 28 patients with MPS VI, who had not undergone specific treatment. All patients were assessed for amplitude of joint mobility (shoulder, elbow, and knee), grip and pinch strength and urinary GAG excretion and also performed the 6MWT. RESULTS: Shoulder flexion exhibited the greatest limitation, with no correlation with age, followed by knee extension and elbow flexion, both of which were correlated inversely with age. Hand grip strength was compromised in all patients, and pinch strength exhibited a positive correlation with age. CONCLUSIONS: The fact that restricted shoulder flexion was not correlated with age suggests that this finding is present early on in MPS VI and that it constitutes an important clinical sign that should arouse diagnostic suspicion of this disease. The amplitude of knee extension and elbow flexion, in turn, are possible markers of disease progression since they have a negative correlation with age. Further studies are needed to confirm these hypotheses.