Last modified: 2014-04-03
Abstract
Objective: Mucopolysaccharidosis type VI is a rare autosomal recessive storage disorder, caused by a deficiency of arylsulfatase B. Data on neurological involvement in mucopolysaccharidosis type VI patients under enzyme-replacement therapy are limited. This study explores the neurological and magnetic resonance imaging findings in a sample of mucopolysaccharidosis type VI patients receiving enzyme-replacement therapy.
Methodos: We performed a cross-sectional study including six patients with biochemical confirmation of mucopolysaccharidosis type VI and at least two consecutive years receiving intravenous enzyme-replacement. The protocol included a comprehensive clinical examination, brain and spinal cord magnetic resonance imaging for all subjects.
Results: Overall, cognition was spared, while we found presence of hearing impairment, increasing in deep tendon reflexes and deep sensation reduction in three patients (table 1). In addition to the classical mucopolysaccharidosis abnormalities, brain image studies demonstrated (fig.1 and 2A): i-morphological changes in anatomy of middle cranial fossa; ii-sella shape abnormalities; iii-diploic thickness over venous sinus; iv-dolicochephaly; v-and sinus pericranii. Even in asymptomatic or mild compromised patients, spinal cord compression was found. In four patients we noticed atlantoaxial joint subluxation and three had cervical spinal stenosis. Degenerative processes involving vertebral column, including vertebral bodies indentations, disc-osteophyte complexes, and Schmorl’s nodes were present in all patients (fig.2B and 3).
Conclusions: Neuroaxis involvement was a constant finding; unfortunately, neurological examination might not predict the severity of the disease in course. Moreover, imaging studies should not be performed according exclusively clinical parameters, once we have demonstrated that neurological involvement may be silent in mucopolysaccharidosis type VI.
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References
1. Valayannopoulos V, Nicely H, Harmatz P, Turbeville S. Mucopolysaccharidosis VI. Orphanet J Rare Dis 2010;5:5.
2. Solanki GA, Alden TD, Burton BK, Giugliani R, Horovitz DD, Jones SA, et al. A multinational, multidisciplinary consensus for the diagnosis and management of spinal cord compression among patients with mucopolysaccharidosis VI. Mol Genet Metab. 2012 Sep;107(1-2):15-24.
3. Horovitz DD, Magalhães TeS, Pena e Costa A, Carelli LE, Souza e Silva D, de Linhares e Riello AP, et al. Spinal cord compression in young children with type VI mucopolysaccharidosis. Mol Genet Metab 2011;104:295-300.
4. Jurecka A, Opoka-Winiarska V, Jurkiewicz E, Marucha J, Tylki-Szymańska A. Spinal Cord Compression in Maroteaux-Lamy Syndrome: Case Report and Review of the Literature with Effects of Enzyme Replacement Therapy. Pediatr Neurosurg 2012;48:191-8.
5. Peterson DI, Bacchus H, Seaich L, Kelly TE. Myelopathy associated with Maroteaux-Lamy syndrome. Arch Neurol 1975;32:127-9.