Clinical and biochemical study of 28 patientswith mucopolysaccharidosis type VI

This paper presents data collected by a Brazilian center in amultinational multicenter observational study of patients withmucopolysaccharidosis type VI (MPS VI), aiming at determining theepidemiological, clinical, and biochemical profile of these patients.Twenty-eight south-American patients with MPS VI were evaluatedthrough medical interview, physical exam, echocardiogram,electrocardiogram, ophthalmologic evaluation, quantification ofglycosaminoglycans (GAGs) in urine, and measurement of the activityof N-acetylgalactosamine-4-sulfatase (ARSB) in leukocytes. 92.9percent ofpatients were Brazilian. Mean age at diagnosis and at evaluation was48.4 months and 97.1 months, respectively. 88 percent of patients had onset ofsymptomatology before the age of 36 months. Consanguinity wasreported by 27 percent of the families. Mean weight and height at birth were3.481 kg and 51.3 cm, respectively. The most frequently reported clinicalmanifestations were short stature, corneal clouding, coarse facialfeatures, joint contractures, and claw hands. All patients presented withechocardiogram changes as well as corneal clouding. Mean ARSBactivity in leukocytes was 5.4nmoles/h/mg protein (reference values:72 174), and urinary excretion of GAGs was on average 7.9 times higherthan normal. The number of clinical manifestations did not show asignificant correlation with the levels of urinary GAGs nor with theARSB activity. Also, no significant correlation was found between thelevels of urinary GAGs and the ARSB activity. It was concluded thatMPS VI has high morbidity and that, when compared with datapublished in the literature, patients in our study were diagnosed laterand presented with a higher frequency of cardiological findings