The natural history and burden of illness of metachromatic leukodystrophy: a systematic literature review

BACKGROUND

Metachromatic leukodystrophy (MLD; OMIM 250100 and 249900) is a rare lysosomal storage disease caused by deficient arylsulfatase A activity, leading to accumulation of sulfatides in the nervous system. This systematic literature review aimed to explore the effect of MLD on the lives of patients.

METHODS

The Ovid platform was used to search Embase, MEDLINE, and the Cochrane Library for articles related to the natural history, clinical outcomes, and burden of illness of MLD; congress and hand searches were performed using 'metachromatic leukodystrophy' as a keyword. Of the 531 publications identified, 120 were included for data extraction following screening. A subset of findings from studies relating to MLD natural history and burden of illness (n = 108) are presented here.

RESULTS

The mean age at symptom onset was generally 16-18 months for late-infantile MLD and 6-10 years for juvenile MLD. Age at diagnosis and time to diagnosis varied widely. Typically, patients with late-infantile MLD presented predominantly with motor symptoms and developmental delay; patients with juvenile MLD presented with motor, cognitive, and behavioral symptoms; and patients with adult MLD presented with cognitive symptoms and psychiatric and mood disorders. Patients with late-infantile MLD had more rapid decline of motor function over time and lower survival than patients with juvenile MLD. Commonly reported comorbidities/complications included ataxia, epilepsy, gallbladder abnormalities, incontinence, neuropathy, and seizures.

CONCLUSIONS

Epidemiology of MLD by geographic regions, quantitative cognitive data, data on the differences between early- and late-juvenile MLD, and humanistic or economic outcomes were limited. Further studies on clinical, humanistic (i.e., quality of life), and economic outcomes are needed to help inform healthcare decisions for patients with MLD.

Gross Motor Function in Pediatric Onset TUBB4A-Related Leukodystrophy: GMFM-88 Performance and Validation of GMFC-MLD in TUBB4A

TUBB4A pathogenic variants are associated with a spectrum of neurologic impairments including movement disorders and leukodystrophy. With the development of targeted therapies, there is an urgent unmet need for validated tools to measure mobility impairment. Our aim is to explore gross motor function in a pediatric-onset TUBB4A-related leukodystrophy cohort with existing gross motor outcome tools. Gross Motor Function Measure-88 (GMFM-88), Gross Motor Function Classification System (GMFCS-ER), and Gross Motor Function Classification-Metachromatic Leukodystrophy (GMFC-MLD) were selected through face validity. Subjects with a confirmed clinical and molecular diagnosis of TUBB4A-related leukodystrophy were enrolled. Participants' sex, age, genotype, and age at disease onset were collected, together with GMFM-88 and concurrent GMFCS-ER and GMFC-MLD. Performances on each measure were compared. GMFM-88 floor effect was defined as total score below 20%. A total of 35 subjects participated. Median performance by GMFM-88 was 16.24% (range 0-97.31), with 42.9% (n = 15) of individuals performing above the floor. GMFM-88 Dimension A (Lying and Rolling) was the best-performing dimension in the GMFM-88 (n = 29 above the floor). All levels of the Classification Scales were represented, with the exception of the GMFC-MLD level 0. Evaluation by GMFM-88 was strongly correlated with the Classification Scales (Spearman correlations: GMFCS-ER:GMFM-88 r = 0.90; GMFC-MLD:GMFM-88 r = 0.88; GMFCS-ER:GMFC-MLD: r = 0.92). Despite overall observation of a floor effect, the GMFM-88 is able to accurately capture the performance of individuals with attenuated phenotypes. GMFM-88 Dimension A shows no floor effect. GMFC-MLD shows a strong correlation with GMFCS-ER and GMFM-88, supporting its use as an age-independent functional score in TUBB4A-related leukodystrophy.

Pearls & Oy-sters: Tumefactive Demyelinating Lesions With MOG Antibodies Preceding Late Infantile Metachromatic Leukodystrophy

The development of acute neurologic dysfunction associated with tumefactive demyelinating lesions and mild diffuse involvement of the corpus callosum has been described in children as a sentinel event that may allow diagnosis of juvenile metachromatic leukodystrophy (MLD) at an early and potentially treatable stage. We report a child who developed this clinico-radiologic pattern associated with myelin oligodendrocyte glycoprotein antibodies several months before the onset of progressive symptoms of late infantile MLD.

Abnormalities of acid-base balance and predisposition to metabolic acidosis in Metachromatic Leukodystrophy patients

Metachromatic Leukodystrophy (MLD; MIM# 250100) is a rare inherited lysosomal storage disorder caused by the deficiency of Arylsulfatase A (ARSA). The enzymatic defect results in the accumulation of the ARSA substrate that is particularly relevant in myelin forming cells and leads to progressive dysmyelination and dysfunction of the central and peripheral nervous system. Sulfatide accumulation has also been reported in various visceral organs, although little is known about the potential clinical consequences of such accumulation. Different forms of MLD-associated gallbladder disease have been described, and there is one reported case of an MLD patient presenting with functional consequences of sulfatide accumulation in the kidney. Here we describe a wide cohort of MLD patients in whom a tendency to sub-clinical metabolic acidosis was observed. Furthermore in some of them we report episodes of metabolic acidosis of different grades of severity developed in acute clinical conditions of various origin. Importantly, we finally show how a careful acid-base balance monitoring and prompt correction of imbalances might prevent severe consequences of acidosis.

Metachromatic leukodystrophy: Disease spectrum and approaches for treatment

Metachromatic leukodystrophy is an inherited lysosomal disorder caused by recessive mutations in ARSA encoding arylsulfatase A. Low activity of arylsulfatase A results in the accumulation of sulfatides in the central and peripheral nervous system leading to demyelination. The disease is classified in a late-infantile, juvenile and adult onset type based on the age of onset, all characterized by a variety of neurological symptoms, which eventually lead to death if untreated. There is no curative treatment for all types and stages. This review discusses diagnostic process and efficacy of current and possible future therapies such as hematopoietic stem cell transplantation, enzyme replacement therapy and gene therapy. A systematic evaluation regarding the efficacy of hematopoietic stem cell transplantation and a longer follow up period for gene therapy are needed to come to a general conclusion and improve treatment options for metachromatic leukodystrophy.

Dopamine-deficiency-enhanced hyperthermia and rhabdomyolysis during a heat wave in a metachromatic leucodystrophy heterozygote with metabolic myopathy

Whether a dopamine-deficiency syndrome in a Parkinson-syndrome (PS) may occur more easily during a heat wave than during more temperate climate conditions is unknown. We report a case that may suggest this. A 56 yo male with heterozygosity for metachromatic leucodystrophy and a history of metabolic myopathy, PS and diabetes experienced worsening of the PS during a heat wave. His condition further deteriorated upon reduction of ropinirol, resulting in hyperthermia, respiratory insufficiency, rhabdomyolysis, and severe thrombocytopenia. One month later he was alert but tetraplegic and required ventilatory support. Hyper-CK-emia returned to similar levels as before rhabdomyolysis. Reduction of dopamine agonists during a heat wave may induce a dopamine deficiency syndrome with hyperthermia, rhabdomyolysis and thrombocytopenia.

Haematopoietic stem cell transplantation does not retard disease progression in the psycho-cognitive variant of late-onset metachromatic leukodystrophy

Haematopoietic stem cell transplantation has an unproven role in the management of late-onset metachromatic leukodystrophy: theoretically justified through the engraftment of enzyme-replete haematopoietic progenitors and restoration of capacity for sulphatide catabolism in neural tissue through enzyme recapture, the long-term outcome is unknown. The rarity of the psycho-cognitive variant and slow progression of late-onset disease impairs evaluation of treatment. We report detailed clinical and neuropsychological assessments after haematopoietic stem-cell transplantation in a patient with a late-onset psycho-cognitive form of metachromatic leukodystrophy. Cognitive decline, indistinguishable from the natural course of the disease, was serially documented over 11 years despite complete donor chimaerism and correction of leukocyte arylsulphatase A to wild type values; subtle motor deterioration was similarly noted and progressive cerebral volume loss was evident upon magnetic resonance imaging. Sensory nerve conduction deteriorated 17 months post-transplantation with apparent stabilisation at 11-year review. Haematopoietic stem-cell transplantation was ineffective for this rare attenuated variant of metachromatic leukodystrophy. In the few patients identified pre-symptomatically or with early-phase disease, clear recommendations are lacking; when transplantation is considered, umbilical cord blood grafts from enzyme-replete donors with adjunctive mesenchymal stem cell infusions from the same source may be preferable. Improved outcomes will depend on enhanced awareness and early diagnosis of the disease, so that promising interventions such as genetically modified, autologous stem cell transplantation have the best opportunity of success.

Sublingual atropine drops for the treatment of pediatric sialorrhea

Excess oral secretions or sialorrhea is a common problem affecting children and adults with neurological disorders, as well as those approaching the end of life because of a variety of underlying illnesses. Systemic anticholinergic medications are often prescribed in an attempt to improve quality of life and reduce complications; yet, response rates are variable, and a sizable proportion of patients discontinue these drugs as a result of intolerable side effects. This report describes the successful use of a local treatment, sublingually delivered ophthalmic atropine drops, to reduce sialorrhea in a child receiving palliative care. In addition, medical evidence for the safety and efficacy of traditionally prescribed systemic medications for the treatment of pediatric sialorrhea is reviewed.

Increasing sulfatide synthesis in myelin-forming cells of arylsulfatase A-deficient mice causes demyelination and neurological symptoms reminiscent of human metachromatic leukodystrophy

Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by the deficiency of arylsulfatase A (ASA). This results in accumulation of sulfated glycosphingolipids, mainly 3-O-sulfogalactosylceramide (sulfatide), in the nervous system and various other organs. In patients, lipid storage causes a progressive loss of myelin leading to various neurological symptoms. The sulfatide storage pattern in ASA-deficient [ASA(-/-)] mice is comparable to humans, but regrettably, the mice do not mimic the myelin pathology. We reasoned that increasing sulfatide storage in this animal model might provoke demyelination. Therefore, we generated transgenic ASA(-/-) [tg/ASA(-/-)] mice overexpressing the sulfatide-synthesizing enzyme galactose-3-O-sulfotransferase-1 in myelinating cells. Indeed, these tg/ASA(-/-) mice displayed a significant increase in sulfatide storage in brain and peripheral nerves. Mice older than 1 year developed severe neurological symptoms. Nerve conduction velocity was significantly reduced in tg/ASA(-/-) mice because of a peripheral neuropathy characterized by hypomyelinated and demyelinated axons. Inhomogeneous myelin thickness in the corpus callosum, increased frequency of hypomyelinated and demyelinated axons in corpus callosum and optic nerve, and substantially reduced myelin basic protein levels are in accordance with loss of myelin in the CNS. Thus, increasing sulfatide storage in ASA(-/-) mice leads to neurological symptoms and morphological alterations that are reminiscent of human MLD. The approach described here may also be applicable to improve other mouse models of lysosomal as well as nonlysosomal disorders.

Sulfatide storage in neurons causes hyperexcitability and axonal degeneration in a mouse model of metachromatic leukodystrophy

Metachromatic leukodystrophy is a lysosomal storage disorder caused by deficiency in the sulfolipid degrading enzyme arylsulfatase A (ASA). In the absence of a functional ASA gene, 3-O-sulfogalactosylceramide (sulfatide; SGalCer) and other sulfolipids accumulate. The storage is associated with progressive demyelination and various finally lethal neurological symptoms. Lipid storage, however, is not restricted to myelin-producing cells but also occurs in neurons. It is unclear whether neuronal storage contributes to symptoms of the patients. Therefore, we have generated transgenic ASA-deficient [ASA(-/-)] mice overexpressing the sulfatide synthesizing enzymes UDP-galactose:ceramide galactosyltransferase (CGT) and cerebroside sulfotransferase (CST) in neurons to provoke neuronal lipid storage. CGT-transgenic ASA(-/-) [CGT/ASA(-/-)] mice showed an accumulation of C18:0 fatty acid-containing SGalCer in the brain. Histochemically, an increase in sulfolipid storage could be detected in central and peripheral neurons of both CGT/ASA(-/-) and CST/ASA(-/-) mice compared with ASA(-/-) mice. CGT/ASA(-/-) mice developed severe neuromotor coordination deficits and weakness of hindlimbs and forelimbs. Light and electron microscopic analyses demonstrated nerve fiber degeneration in the spinal cord of CGT/ASA(-/-) mice. CGT/ASA(-/-) and, to a lesser extent, young ASA(-/-) mice exhibited cortical hyperexcitability, with recurrent spontaneous cortical EEG discharges lasting 5-15 s. These observations suggest that SGalCer accumulation in neurons contributes to disease phenotype.

[Frontotemporal dementia in metachromatic leukodystrophy]

The case of a 39-year old woman with metachromatic leukodystrophy (MLD) is presented. In the clinical examination she revealed symptoms of a frontotemporal dementia without any signs of polyneuropathy. If frontotemporal dementia is diagnosed MLD should be excluded.

Sedation for children with metachromatic leukodystrophy undergoing MRI

BACKGROUND

Metachromatic leukodystrophy (MLD) is a lysosomal storage disease with infantile and juvenile onset with a poor prognosis and magnetic resonance imaging (MRI) plays a fundamental role in its diagnosis. Procedural sedation is needed to carry out MRI on children. Very few case reports have been published on anesthesia or sedation for MLD patients.

METHODS

We prospectively studied 18 MLD patients undergoing sedation for brain MRI. Twenty consecutive similar-aged ASA I children undergoing MRI during the same time span for suspected seizures and exhibiting no MRI brain alteration healthy (HLT) patients were also studied for comparison. In patients up to 3 years of age (T_MLD and T_HLT groups), sedation was induced with thiopental 5 mg x kg(-1) i.v. and further 2.5 mg x kg(-1) i.v. rescue boluses were given if the sedation level was inadequate. In patients over 3 years of age (P_MLD and P_HLT groups), sedation was induced with propofol 1-1.5 mg x kg(-1) i.v. and maintained with 0.1-0.15 mg x kg(-1) x min(-1) continuous i.v. infusion, which was increased if the sedation level was inadequate. We recorded complications, if any, caused by sedation (hypoxia, vomiting, bradycardia, other major arrhythmias, convulsions, MRI artifact movements with increasing sedation, prolonged recovery).

RESULTS

No sedation complications occurred. The mean dose of thiopental required to warrant patient immobility was 0.227 +/- 0.053 mg x kg(-1) x min(-1) of procedure in T_MLD patients and 0.119 +/- 0.061 mg x kg(-1) x min(-1) of procedure in T_HLT patients (difference not significant). The mean dose of propofol required for immobility was 0.119 +/- 0.054 mg x kg(-1) x min(-1) of procedure in T_MLD patients and 0.115 +/- 0.043 mg x kg(-1) x min(-1) of procedure in T_HLT patients (difference not significant).

CONCLUSIONS

Our protocol for sedation in the MRI setting proved safe and effective in children with MLD, who do not require different doses of sedatives compared with healthy children.

Peripheral neuropathy in metachromatic leucodystrophy. A study of 40 cases from south India

BACKGROUND

There is a paucity of literature from India on metachromatic leucodystrophy (MLD), a rare metabolic disorder of childhood resulting from aryl sulfatase A (ASA) deficiency.Patients/

METHODS

Case records of histopathologically verified cases of MLD, evaluated over a period of 12 years at the National Institute of Mental Health and Neurosciences, Bangalore, India, were reviewed.

RESULTS

The late infantile group (36) manifested with regression of milestones (all), delayed mile stones (14), gait abnormalities (14), and seizures (11). Despite spasticity (29), there was hypo/areflexia in 25 patients. Optic atrophy (six) was rare. Consanguinity was noted in 25 children and four had a history of similar illness in siblings. Behavioural problems dominated in the juvenile group (four), but associated cognitive decline and hyporeflexia provided a clue to the diagnosis. Low serum ASA (seven of 20), raised cerebrospinal fluid protein (five of 12), and urinary metachromatic granules (two of 32) were infrequent. Electrophysiological evidence of severe demyelinating and length dependent sensory motor neuropathy was observed in all, even in the presence of hyper-reflexia. In addition to metachromatic dysmyelinating neuropathy in all patients, sural nerve biopsy in 20 patients revealed orthochromatic deposits within perivascular macrophages, particularly among those patients with normal ASA values (11 of 14), suggesting the accumulation of other glycosphingolipids.

CONCLUSIONS

This study produced some noteworthy observations: the high degree of consanguinity associated with MLD in India, the existence of MLD with normal serum concentrations of ASA, the deposition of orthochromatic lipids, and electrophysiological evidence of a partial conduction block.

[Disorders of concentration and memory in young adults and middle-aged persons]

Four patients, two women aged 29 and 52 and two men aged 46 and 25, respectively, consulted a neurologist for attention and memory disorders. Further investigation revealed that the symptoms were caused by metachromatic leucodystrophy, Graves' disease, Huntington's disease, and a psychological background, respectively. The first patient became dependent in 1.5 years, the second recovered after treatment, the third was independent with slowly progressive symptoms after 1 year, and the fourth was advised to consult a psychologist. Disorders of attention and memory in relatively young people deserve a detailed evaluation at the very first visit, involving the elaboration of an initially extensive differential diagnosis. Too early a separation between a psychic and an organic pathogenesis should be avoided. Indications for the presence of a neurological condition include: consultation at the initiative of others, a relatively brief duration of symptoms without a clear provoking factor, the absence of a psychiatric history or life event, cognitive dysfunction in several areas, abnormal behaviour and an incriminating family history.

Adult metachromatic leukodystrophy: disorganized schizophrenia-like symptoms and postpartum depression in 2 sisters

We describe the cases of 2 sisters with adult metachromatic leukodystrophy (MLD). Whereas one sister presented with disorganized schizophrenia-like symptoms as the initial manifestation of MLD, the other remained symptom free except for a 4-week period of postpartum depression. In both patients, there was some residual activity of leukocyte arylsulfatase A (1.7% and 5.5% of normal), and a marked increase in urinary sulfatides was present, as measured by tandem mass spectrometry. An arylsulfatase A pseudodeficiency was therefore excluded. The most common mutations of the adult phenotype, Ile-179-Ser and Pro-426-Leu, were not found. In the literature, only 1 case of adult MLD manifesting as disorganized schizophrenia-like symptoms has been described, whereas postpartum depression has been so far unknown as a presenting symptom of MLD.

[Early onset dementias: three cases]

INTRODUCTION

Dementia is a decline of intellectual abilities. The etiology of dementia syndrome is diverse. The authors describe three patients with early-onset dementia.

CASE REPORTS

The first patient was a 44 years old male with mild gait, body ataxia, memory loss, slowness and apathy Investigations proved AIDS dementia syndrome. In the second case of a 37 years old female patient, herpes simplex encephalitis was suspected due to sudden onset of speech arrest and to brain MRI and CSF findings. Her symptoms improved during antiviral treatment but later progressive dementia developed. CSF serological tests proved the presence of neurolues-dementia paralytica. The third patient was a 38-years-old female. Neurological examination was performed because of progressive memory loss, changed behaviour and impaired attention. Neuropsychological test showed severe dementia. Metachromatic leukodystrophy was proven by decreased arylsulfatase activity.

CONCLUSIONS

It is not easy to recognize the early symptoms of dementia. In these cases, besides detailed history, neurological examination and neuropsychological tests, brain MRI and cerebral spinal fluid serological tests were indispensable for a correct diagnosis, especially in the young patients.

Anaesthetic management in children with metachromatic leukodystrophy

We present a case of metachromatic leukodystrophy in a child who required surgery for gastro-oesophageal reflux. In spite of his demyelinating disease, we used a lumbar epidural technique with general anaesthesia; the epidural catheter allowed us to continue the analgesia postoperatively and to avoid opioids in this high risk patient.

Metachromatic leukodystrophy: diffusion MR imaging findings

Herein the case of a 10-month-old boy with metachromatic leukodystrophy is reported. Diffusion MR imaging performed with an echo-planar trace sequence revealed a cytotoxic edema-like pattern (high signal intensity on b = 1000 s/mm(2) images and low apparent diffusion coefficient values) in the affected white matter in the absence of an ischemic condition. This finding was unchanged at a 6-month follow-up, as revealed by diffusion MR imaging. A gradient-echo diffusion sequence, reverse fast imaging in steady-state precession, revealed hyperintense changes at the corresponding regions. It is likely that the cytotoxic edematous pattern (restricted diffusion pattern) reflected restriction of mobility of the water molecules within abnormal portions of the myelin sheath, because impaired myelin breakdown and reutilization are known features of metachromatic leukodystrophy.

Investigations of micro-organic brain damage (MOBD) in heterozygotes of metachromatic leukodystrophy

Potential damage of central and peripheral nervous system expressed as micro-organic brain damage (MOBD) was investigated in 27 unrelated heterozygotes with metachromatic leukodystrophy (MLD). Arylsulfatase A (ARSA) was determined in peripheral blood leukocytes and sulfatide excretion was estimated in 24-hour urine collections. Genomic DNA was analyzed for the ARSA pseudodeficiency (PD) allele by a PCR method. Clinical investigations included examination of hyper-reflexia, Babinski reflex, Wechsler Adult Intelligence Scale, Benton test, evoked potentials, and nerve conduction velocity (NCV). In our study, a higher incidence of evident or possible micro-organic brain damage was observed in true MLD/PD and MLD heterozygotes (NO/MLD, where NO means the wild allele) than in controls. On the basis of the Benton test, MOBD was suggested or indicated in 67% of MLD heterozygotes, 50% of MLD/PD heterozygotes, and 26% of controls. In our small group of carriers with MLD and PD mutations, persons NO/MLD(PD) with one wild-type allele did not show MOBD and displayed higher ARSA/beta-galactosidase ratios, unlike true MLD/PD compound heterozygotes who carry MLD-causing mutation in one allele and the ARSA-PD polymorphism in the second. Theoretically, this is a shift from autosomal recessive to autosomal dominant-like inheritance, especially when one cannot exclude the influence of polymorphisms (like ARSA-PD) in the wild allele. Since all psychological tests were age-matched, it can be assumed that the MOBD observed in MLD carriers does not have a progressive character unlike in MLD patients. However, it should be mentioned that MOBD appears to have no overt clinical consequences.

[Metachromatic leukodystrophy symptoms in an adult. Case report]

Metachromatic leukodystrophy is a genetic metabolic disease which generally occurs in childhood, surprisingly it can also occur during adulthood. Adult forms have very often characteristic presentations with progressive dementia. The authors presented a case of metachromatic leukodystrophy in an adult, differential diagnosis and examinations which possible made diagnosis.

Hemorrhagic cholecystitis as a likely cause of nontraumatic hemobilia in metachromatic leukodystrophy: report of a case

A 17-years-old man with the juvenile form of MLD developed massive hemobilia. CT and US scans showed blood and clots filling the gallbladder and the biliary ways, with no bleeding source seen at selective angiography. Explorative laparotomy evidenced bleeding from a papillomatous gallbladder mucosa, resolved with cholecystectomy. Histologic examination with specific colorations diagnosed hemorrhagic cholecystitis from metachromatic leukodystrophy of the gallbladder. This is, to our knowing, the third case reported in Literature, and thus hemorrhagic cholecystitis may be considered a life-threatening complication of MLD to be prevented with cholecystectomy as soon as signs of gallbladder pathology (papillomatosis/polyposis, jaundice, abdominal pain) are suspected.

Unusual clinical presentation in two cases of multiple sulfatase deficiency

Multiple sulfatase deficiency (MSD) is an inborn error of metabolism that combines the clinical features of late infantile metachromatic leukodystrophy and mucopolysaccharidosis. The characteristic biochemical abnormality is a reduction in the activities of several sulfatases, with consequent tissue accumulation of sulfatides, sulfated glycosaminoglycans, sphingolipids, and steroid sulfates. In this study we present two unusual cases of MSD with variable enzymatic deficiency of arylsulfatases A, B, and C. Both patients had ichthyosis, broad thumbs and index fingers, an unusually slow progression of the neurologic symptoms, and lacked the hepatosplenomegaly that is typical of MSD. Olivopontocerebellar atrophy was present and one patient had a large retrocerebellar cyst. Mucopolysaccharides were not detected in the urine from either subject. Leukocyte arylsulfatase A activity in patient 1 was 0.46 nmol/mg protein/hr and in patient 2 was 0.0 nmol/mg protein/hr (normal 0.7-5.0 nmol/mg protein/hr). Leukocyte arylsulfatase B activity in patient 1 was 24 nmol/mg protein/hr and in patient 2 was 22 nmol/mg protein/hr (normal 115-226 nmol/mg protein/hr). Leukocyte arylsulfatase C in patient 1 was 0.30 pmol/mg protein/hr and in patient 2 was 0.28 pmol/mg protein/hr (normal 0.84 pmol/mg protein/hr). In conclusion, these two patients with MSD had mild clinical presentations not previously reported and variable enzymatic deficiency of arylsulfatases A, B, and C.

In vivo gene therapy of metachromatic leukodystrophy by lentiviral vectors: correction of neuropathology and protection against learning impairments in affected mice

Metachromatic leukodystrophy (MLD) is a lipidosis caused by deficiency of arylsulfatase A (ARSA). Although the genetics of MLD are known, its pathophysiology is not understood. The disease leads to progressive demyelination and early death and no effective treatment is available. We used lentiviral vectors to deliver a functional ARSA gene (human ARSA) into the brain of adult mice with germ-line inactivation of the mouse gene encoding ARSA, As2. We report sustained expression of active enzyme throughout a large portion of the brain, with long-term protection from development of neuropathology and hippocampal-related learning impairments. We show that selective degeneration of hippocampal neurons is a central step in disease pathogenesis, and provide evidence that in vivo transfer of ARSA by lentiviral vectors reverts the disease phenotype in all investigated areas. Therefore, in vivo gene therapy offers a unique option for MLD and other storage diseases affecting the central nervous system.

Dementia with impaired temporal glucose metabolism in late-onset metachromatic leukodystrophy

An unusual case of very-late-onset metachromatic leukodystrophy (MLD) with dementia was studied. The patient was a 41-year-old male who presented with mild dementia and a single generalized tonic clonic seizure. Neuropsychological assessment demonstrated mild amnesia, visuospatial dysfunction and attention deficits with a slow psychomotor speed. MR brain imaging displayed confluent hyperintensities of periventricular and subcortical white matter. Low levels of arylsulfatase A confirmed the diagnosis. Impaired cortical glucose metabolism especially of the medial temporal and frontal cortices was observed using positron emission tomography and fluor-18-labeled fluorodesoxyglucose. The neuropsychological deficits are related to the location of deficits in glucose metabolism.

Seizures as a presenting feature of late onset metachromatic leukodystrophy

OBJECTIVES

We describe 2 patients with epilepsy as an early manifestation of late onset metachromatic leukodystrophy (MLD).

METHODS AND RESULTS

The first patient presented with epileptic seizures at the age of 34 years while neurological and cognitive abnormalities appeared later. MRI findings were compatible with leukodystrophy and low levels of arylsulphatase-A activity confirmed MLD. The second patient developed epileptic seizures and behavioral disturbances at the age of 19 years. She remained stable and seizure free for 8 years. Afterwards she developed uncontrolled epileptic seizures and status epilepticus as well as neurological and cognitive impairment. Leukodystrophy was diagnosed by MRI findings and low levels of arylsulphatase-A activity were compatible with MLD.

CONCLUSION

Our 2 cases postulate that epileptic seizures may be an early and prominent manifestation of late onset MLD.

Spontaneous rupture of the diaphragm

A 2.5 year old girl with metachromatic leukodystrophy presented with acute respiratory distress and was initially wrongly diagnosed with pneumothorax. Barium meal showed bowel loops in the left hemithorax, which prompted surgical intervention; spontaneous rupture of the diaphragm was diagnosed at surgery.

Early thalamic and cortical hypometabolism in adult-onset dementia due to metachromatic leukodystrophy

A case of early-onset adult dementia with family history of dementia is reported, characterised by neuropsychological deficits, suggesting frontal involvement, with mild non specific white matter abnormalities on CT scan. Familial Alzheimer's disease was suspected but the neuropathological diagnosis on brain biopsy was metachromatic leukodystrophy. 18FDG-PET revealed a very peculiar pattern of metabolic impairment in thalamic areas, in medial and frontopolar regions, and in occipital lobes. Neuropsychological follow-up showed relatively stable difficulties of long-term memory and signs of frontal lobe dysfunction, similar to those observed in subcortical dementias. MRI subsequently showed periventricular leukoencephalopathy. The brain metabolic pattern observed in that case of metachromatic leukodystrophy was quite different from that reported in other types of dementia.

Unusual gallbladder findings in two brothers with metachromatic leukodystrophy

Characteristic biliary tree abnormalities in metachromatic leukodystrophy (MLD) include gallbladder polyposis and haemobilia. We report two brothers with MLD, who presented with uncommon biliary complications. One presented with gastric outlet obstruction secondary to gallbladder enlargement, which was treated by percutaneous aspiration. He later developed gallbladder carcinoma with liver metastases. His brother demonstrated US findings consistent with gallstones.

Ichthyosis: the skin manifestation of multiple sulfatase deficiency

Juvenile sulfatidosis (Austin type) or multiple sulfatase deficiency is an extremely rare autosomal recessive disorder affecting the activity of many sulfatases: arylsulfatase A, several mucopolysaccharide sulfatases, and steroid sulfatase. Certain aspects of the clinical phenotype can be attributed mainly to a deficiency of one specific sulfatase. Most patients develop metachromatic leukodystrophy caused by arylsulfatase A deficiency, dysostosis multiplex by mucopolysaccharide sulfatase deficiency, and ichthyotic skin by steroid sulfatase deficiency. We describe a 7-year-old boy with developmental delay from 7 months of age, progressive spastic quadriparesis, and coarse facial features. By 27 months of age, an ichthyotic rash had developed on the limbs, trunk, and scalp. A skin biopsy specimen revealed hyperkeratosis with a normal granular layer. The diagnosis of multiple sulfatase deficiency was demonstrated by measuring sulfatase activities in fresh leukocytes: there were large deficiencies of arylsulfatase A and B plus reduced arylsulfatase C. The ichthyosis associated with multiple sulfatase deficiency has an autosomal recessive inheritance, is caused by steroid sulfatase deficiency, and the scaling is sometimes milder than in X-linked recessive ichthyosis. This could reflect the residual activity of steroid sulfatase in some cases.

An unusual presentation in a patient with metachromatic leukodystrophy

A 2-year-old child was admitted with bilateral bronchopneumonia. During convalescence he sustained sudden respiratory arrest for which he required ventilatory support. He had undergone cholecystectomy 1 month prior to the above episode. The pathological examination of the gall bladder mass had revealed the features of metachromatic leukodystrophy. Gastro-oesophageal reflux, which is associated with this neurological disorder, was suspected to be the cause of this sudden respiratory arrest and its presence was confirmed by barium swallow examination.

Papillomatosis of the gallbladder in metachromatic leukodystrophy

A 2-year-old boy who presented with a cystic gallbladder mass was found histologically to have metachromatic leukodystrophy. Diffuse hyperplasia of the gallbladder mucosa, multiple tendrillar fronds extending into the lumen, extensive papillomatosis, and the presence of large numbers of macrophages bearing metachromatic material confirmed the diagnosis. The child developed progressive degeneration of the central nervous system, refractory bronchopneumonia, and generalized muscular atrophy. A computed tomographic scan of the brain demonstrated hypodense areas of white matter suggestive of demyelination. This report describes the rare association of gallbladder papillomatosis with a storage disorder and reviews the relevant literature.

Metachromatic leukodystrophy: a case report of a child with an equinus deformity

The authors discuss an unusual disorder of myelin metabolism. Initial presentation was due to an unstable gait pattern. Characteristics of the disease and a representative case are evaluated.

Metachromatic leukodystrophy and coincidental finding of papillomatosis of the gallbladder. A case report

In this case report we describe the coincidental finding of polyps in the gallbladder by ultrasound investigation in a six-year-old girl, known to have metachromatic leukodystrophy. The investigation was carried out because of suspicion of abdominal trauma after falling down the stairs and finding elevated serum amylase.

Massive hemobilia and acalculous cholecystitis due to benign gallbladder polyp

A 37-year-old male with metachromatic leukodystrophy, a congenital cerebroside storage disease strongly associated with benign gallbladder polyps, presented with hemobilia and acalculous cholecystitis due to a long, slender, benign gallbladder polyp. This case report extends the clinical spectrum of gallbladder polyps and demonstrates a novel cause of hemobilia. The unusually long, slender polyp shape may have promoted hemorrhage due to the potential for torsion around a slender stalk. The mechanism of cholecystitis may have been cystic duct obstruction from blood clots or possibly from prolapse by the long, slender polyp into the cystic duct.

Polyposis of the gallbladder associated with metachromatic leukodystrophy

We report on two children with metachromatic leukodystrophy and polyposis of the gallbladder. In both patients ultrasound examination revealed a small gallbladder with a thickened echogenic wall and multiple polypoid masses. In one patient diagnosis of gallbladder polyposis was made 6 months before the first neurological symptoms occurred. As gallbladder polyposis is a rare phenomenon in childhood, metachromatic leukodystrophy should be excluded.

Partial seizures in two cases of metachromatic leukodystrophy: electrophysiologic and neuroradiologic findings

This report concerns two cases of metachromatic leukodystrophy presenting partial seizures. One was a 2-year-old boy with a late infantile type and the other a 17-year-old girl with a juvenile type. The former had tonic-clonic seizures on the left with concomitant twitching of the left side of the face and adversive conjugate deviation of the eyes. After a while, his interictal sleep electroencephalogram (EEG) showed spikes in the right central area. The second case had hemiconvulsions on the right side, consisting mainly of tonic flexion of the upper limb followed by clonic flexions, and accompanied by adversive conjugate deviation of the head and eyes. Her ictal EEG showed rhythmic 6- to 7-Hz wave bursts in the left frontal area. To this date, no report has given a detailed discussion of the type of seizures and ictal EEG in metachromatic leukodystrophy. In addition, there have been few detailed reports of magnetic resonance imaging (MRI) in the juvenile type. It is interesting that typical partial seizures were observed in a hereditary metabolic disorder characterized by diffuse demyelination of the white matter, and the pathophysiology is discussed here mainly in relation to MRI findings of the case with the juvenile type.

Adult-onset metachromatic leukodystrophy presenting as isolated peripheral neuropathy

A 38-year-old man presented with weakness of the lower limbs. Electrophysiology revealed a pronounced demyelinating neuropathy. Nerve biopsy disclosed de- and remyelinating lesions and characteristic lamellar inclusions in Schwann cells and macrophages. There was no familial history of neurologic disorder, and impairment of motor evoked potentials was the only sign of CNS involvement. Arylsulfatase A and cerebroside sulfate sulfatase activities in leukocytes and cultures of the patient's fibroblasts were low. The sulfatide loading test also revealed abnormal sulfatide accumulation. This may be the first reported case of adult metachromatic leukodystrophy presenting as peripheral neuropathy.

[Metachromatic leukodystrophy: an exceptional cause of dementia in the adult]

Hereditary metabolic diseases are an exceptional cause of neurological disorders in adults. Metachromatic leukodystrophy is a hereditary alteration of the metabolism of myelin which may be manifested in adults as intellectual deterioration. A case of metachromatic leukodystrophy presented in adulthood is presented with cognitive deterioration and behavioral alterations as the only clinical manifestation. The patient was a 28 year old male studied for dementia of one year of evolution. Computerized tomography and cranial magnetic resonance demonstrated diffuse and symmetric involvement of the periventricular white matter. The visual evoked potentials were involved while the brain stem auditory potentials were normal. Study of the speed of nerve conductions was compatible with demyelinating neuropathy. The diagnosis of metachromatic leukodystrophy was confirmed by enzyme study revealing very diminished levels of aryl-sulfatase A. Although it is exceptional the adult form of metachromatic leukodystrophy should be included in the differential diagnosis of dementia. Computerized tomography and cranial magnetic resonance together with neurophysiologic studies are the principle procedures orienting diagnosis to this disease.

Psychiatric disturbances in metachromatic leukodystrophy. Insights into the neurobiology of psychosis

Metachromatic leukodystrophy is a rare inherited disorder of the nervous system. Symptoms initially can present during childhood, adolescence, or adulthood. Psychiatric symptoms, including complex auditory hallucinations and bizarre delusions, are a prominent feature of metachromatic leukodystrophy presenting when the patient is between 12 and 30 years. One hundred twenty-nine published case reports were reviewed, focusing on the presence of psychosis. Psychosis was present in 53% of the published case reports of adolescent and early adult-onset metachromatic leukodystrophy, a much higher prevalence than that seen with other primary neurological disorders. The pathological lesion of metachromatic leukodystrophy is demyelination of the central and peripheral nervous systems, particularly the subfrontal white matter, suggesting that psychosis may result from the disruption of corticocortical and corticosubcortical connections, especially involving the frontal lobes. While similar lesions appear in the infantile, juvenile, and late adult forms of metachromatic leukodystrophy, psychotic symptoms were reported only in those cases presenting in adolescence and young adulthood, suggesting that age is another important neurobiological factor in the development of psychosis.

Adult metachromatic leukodystrophy with an unusual relapsing-remitting course

A 46 year old woman had a relapsing-remitting course of hemiparesis, disorientation, paraparesis and seizures, followed by progressive dementia, spasticity and ataxia. Computed tomography at onset showed a parietotemporal hypodense area with diffuse mottled enhancement obliterating the lateral ventricle. Subsequent scans demonstrated symmetric periventricular non-enhancing hypodensities, progressive ventricular enlargement and atrophy. Adult metachromatic leukodystrophy was diagnosed on the basis of low leukocyte arylsulphatase A level and metachromatic material accumulation at neural nerve biopsy.

Repeated upper gastrointestinal hemorrhage caused by metachromatic leukodystrophy of the gall bladder

A 27-year-old man with metachromatic leukodystrophy (MLD) of the adult type had developed repeated severe gastrointestinal (GI) bleeding. During endoscopic retrograde cholangiography (ERC), hemobilia was observed on two occasions. The definite diagnosis was obtained by a biopsy specimen taken from the lumen of the gall bladder during ERC, demonstrating large masses of metachromatic material inside the gall bladder. Upon cholecystectomy, papillomatosis of the gall bladder was found virtually obliterating the lumen of the gall bladder. A blood clot was observed at the angle of the cystic duct; histologic examination revealed diffuse hemorrhage into the stroma of the gall bladder. The patient is without upper GI hemorrhage since 3 years. In patients with MLD and upper GI bleeding, one should, therefore, be aware of the gall bladder as a possible source of hemorrhage.

Adult forms of metachromatic leukodystrophy: clinical and biochemical approach

The clinical and biochemical characteristics of metachromatic leukodystrophy (MLD), true adult forms and late juvenile forms which are still living at adulthood, are reviewed as they both are observed in adult Neurology and Psychiatry departments. Mental deterioration is often the first symptom, evolving progressively; and dementia finally occurs. The latency before the appearance of neurological objective symptoms may be long and extend for several years. In many cases, the behavioral abnormalities are the first symptoms. Some of these forms have been diagnosed as schizophrenia. Very seldom, neurological symptoms, especially ataxia, occur without cognitive or psychiatric disturbances. Most of these cases have pyramidal and cerebellar symptoms, at diverse degrees. Seizures can also occur which is some cases can be early symptoms associated to mental deterioration. The association of central and peripheral neurological symptoms is very characteristic of MLD. The peripheral neuropathy is not generally clinically evidenced, but is rarely missing electrophysiologically. Arylsulfatase A determination should be performed for diagnosis as a first step, and confirmed by the accumulation of sulfatide, either by quantitative determinations in urine or by the sulfatide loading test. It is as yet not clear why certain forms have a rather rapid evolution in 5 years, and others have a very protracted course during decades.