Elsevier

Brain and Development

Volume 23, Issue 6, October 2001, Pages 385-389
Brain and Development

Original article
Serial magnetic resonance imaging findings in mucopolysaccharidosis IIIB (Sanfilippo's syndrome B)

https://doi.org/10.1016/S0387-7604(01)00242-XGet rights and content

Abstract

Sanfillippo B syndrome (mucopolysaccharidosis (MPS) III, type B) is characterized by mild expression of the characteristic ‘Hurler’ phenotype and a severe central nervous system involvement. We report three patients with Sanfilippo B syndrome, referred to our clinic because of peculiar facies, delay in language development and behavioral problems, at the ages of 4, 3 and 5 years, respectively. At presentation they manifested clinical features of MPS, severe developmental retardation, radiological features of dysostosis mutiplex, as well as neurophysiological findings suggestive of carpal tunnel syndrome and sensorineural hearing impairment. Due to marked urinary excretion of heparan sulfate, as well as deficiency of α-N-acetylglucosaminidase in leukocytes, the diagnosis of Sanfilippo B syndrome was made. Serial brain magnetic resonance imaging (MRI) at different ages demonstrated white matter abnormalities, cortical atrophy and ventricular enlargement in all three patients, while other findings included thickening of the diploe in two patients and callosal atrophy, basal ganglia involvement, cerebellar changes and dilatation of venous sinuses in one patient. Although the combination of the above MRI findings is highly suggestive of a MPS, they carry a little predictive value in the different clinical stages of MPS IIIB.

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.

Section snippets

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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