Original articleSerial magnetic resonance imaging findings in mucopolysaccharidosis IIIB (Sanfilippo's syndrome B)
Introduction
Sanfillippo syndrome (mucopolysaccharidosis (MPS) III) is characterized by mild expression of the characteristic ‘Hurler’ phenotype and an almost severe central nervous system (CNS) involvement [1]. It comprises four subtypes A, B, C and D, which, although linked to different enzyme defects, demonstrate a rather homogeneous clinical picture with respect to CNS involvement: mental retardation with specific language and communication problems, seizures and mostly behavioral problems, in contrast to mild involvement of other tissues and organs, usually affected in other MPS [1]. MPS IIIB syndrome is a rare autosomal recessive metabolic disorder caused by deficiency in α-N-acetylglucosaminidase [1]. Neuroimaging in Sanfilippo's syndrome, as well as in the rest of the mucopolysaccharidoses, is usually carried out when hydrocephaly or spinal cord compression is suspected, or alternatively to estimate the degree of CNS involvement at a certain stage of the disease [1], [2], [3]. We report a series of three patients with Sanfilippo B syndrome by whom serial magnetic resonance imaging (MRI) studies, as well as clinical and neurophysiological studies, were undertaken.
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Patients and methods
The three patients were referred to our clinic because of peculiar facies (patient 1), delay in language development (patient 2) and behavioral problems (patient 3), at the ages of 4, 3 and 5 years, respectively. Two of the patients were male and one was female, all born to healthy non-consanguineous parents with a negative family history for neurometabolic or neurodegenerative disorders. Pregnancy and delivery were uneventful as were motor milestones. The first meaningful word was spoken at
MRI findings (Table 2 and Figs. 1–3)
Magnetic resonance of the brain was performed in all patients; T1-weighted images were obtained with SE 500/25, PD-weighted images with SE 2000/35 and T2-weighted images were obtained with SE 2000/100. Patient 1 had three MRI examinations performed at ages 4, 5.5 and 7 years, respectively, patient 2 had 2 MRI examinations performed at ages 4 and 10 years, respectively, and patient 3 had one examination at the age of 13 years.
At first examination at 4 years of age, patients 1 (Fig. 1, left) and
Discussion
Imaging studies of the brain in the MPS are usually ordered when hydrocephalus or spinal cord compression is suspected [2]. There are few reports regarding MRI findings in MPS with CNS involvement [2], [3], [4], [5], most of them demonstrating ventricular enlargement, cortical atrophy and increased signal density in the T1- and T2-weighted images in the periventricular white matter. Occasionally, well-defined foci, isointense with CSF, are seen in the cerebral white matter on all imaging
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