Angelica Rampazzo

Difficulties in diagnosing slowly progressive mucopolysaccharidosis VI: A case series

An Erratum for this article can be found here: http://iospress.metapress.com/content/e16437020701m0u5/?p=df8dd6709cf44367a0c0e5d917aaeddf&pi=11We describe the cases of two adult sisters recently diagnosed with the attenuated form of mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome). MPS VI is a rare, clinically heterogeneous lysosomal storage disorder that is characterized by a deficiency in the glycosaminoglycan-degrading enzyme arylsulfatase B. Both cases had been misdiagnosed for over 30 years despite the presence of several characteristics of the disease, including short stature (mild), coarse facial features, skeletal dysmorphisms, carpal tunnel syndrome, heart valve disease, and spinal cord compression, which together are suggestive of a lysosomal storage disease. Awareness about the clinical features of MPS VI should be communicated amongst treating neurologists, rheumatologists and other specialists who are involved in the healthcare decisions of these patients with presenting symptoms, so they can refer them to specialized centers for proper diagnosis and treatment.

The Role of Visual Electrophysiology in Mucopolysaccharidoses

Visual electrophysiological techniques represent excellent means for assessing retinal, optic pathways and visual cortex function. Electroretinograms, visual evoked potentials, and clinical records of 17 patients with mucopolysaccharidosis registered in the neurophysiological database of our institution were reviewed retrospectively. Ten patients were on enzyme replacement therapy, 2 underwent bone marrow transplantation, one also keratoplasty. Changes in the electroretinogram pointed to the diagnosis of retinal dystrophy type rod-cone in 8 patients. In patients in whom severe corneal clouding precluded fundus oculi inspection and at an early stage before typical fundus appearance diagnosis was possible only using the electroretinogram. Visual evoked potentials were useful to confirm the loss of visual function in patients difficult to test clinically. The authors suggest the use of electroretinogram and visual evoked potentials primarily as research tools to describe the natural history and ophthalmologic outcome in mucopolysaccharidoses, although they may have clinical utility in very selected cases.

Nocturnal frontal lobe epilepsy in mucopolysaccharidosis

Nocturnal frontal lobe epilepsy (NFLE) is an epileptic syndrome that is primarily characterized by seizures with motor signs occurring almost exclusively during sleep. We describe 2 children with mucopolysaccharidosis (MPS) who were referred for significant sleep disturbance. Long term video-EEG monitoring (LT-VEEGM) demonstrated sleep-related hypermotor seizures consistent with NFLE. No case of sleep-related hypermotor seizures has ever been reported to date in MPS. However, differential diagnosis with parasomnias has been previously discussed. The high frequency of frontal lobe seizures causes sleep fragmentation, which may result in sleep disturbances observed in at least a small percentage of MPS patients. We suggest monitoring individuals with MPS using periodic LT-VEEGM, particularly when sleep disorder is present. Moreover, our cases confirm that NFLE in lysosomal storage diseases may occur, and this finding extends the etiologic spectrum of NFLE.

Chiari 1 Malformation and Holocord Syringomyelia in Hunter Syndrome

Compressive cervical myelopathy is a well-known life-threatening complication in mucopolysaccharidosis (MPS) patients. Glycosaminoglycan accumulation in the growing cartilage results in dens dysplasia, atlanto-axial instability, and subsequent periodontoid fibrocartilaginous tissue deposition with upper cervical stenosis.Chiari malformation type 1 (CM1) is a congenital downward cerebellar tonsil ectopia determined by clivus and posterior cranial fossa underdevelopment, possibly leading to progressive spinal cord cavitation (syringomyelia) and severe neurological impairment.We present a boy affected with Hunter syndrome (MPS II) and cerebellar tonsil ectopia who developed a holocord syringomyelia at the age of 6 years. The child underwent atlanto-occipital decompressive surgery with rapid clinical and neuroimaging improvement.Sharing a primary mesenchymal involvement of the cervical-occipital region, the coexistence of CM1 in MPS might be not unexpected and complicate further the disease course. In these patients, strict monitoring and prompt treatment might be of foremost importance for preventing major neurological complications.

The Complexity of Pain Management in Children Affected by Mucopolysaccharidoses

Mucopolysaccharidoses (MPSs) are a group of rare, genetic lysosomal storage disorders. They are caused by deficiencies of the lysosomal enzymes involved in the degradation of glycosaminoglycans (GAGs). Pain is a common feature in mucopolysaccharidoses. However, the pathophysiology of pain in this group of diseases is still unclear and genesis of pain is multifactorial. Currently, poor data about pain management in these patients are available. Here, we present our clinical experience in complex pain management in three children with MPS.