Natural history of Niemann-Pick disease type C in a multicentre observational retrospective cohort study

Induction of cholesterol biosynthesis by archazolid B in T24 bladder cancer cells

BACKGROUND

Resistance of cancer cells towards chemotherapeutics represents a major cause of therapy failure. The objective of our study was to evaluate cellular defense strategies in response to the novel vacuolar H(+)-ATPase inhibitor, archazolid B.

EXPERIMENTAL APPROACH

The effects of archazolid B on T24 bladder carcinoma cells were investigated by combining "omics" technologies (transcriptomics (mRNA and miRNA) and proteomics). Free cholesterol distribution was determined by filipin staining using flow cytometry and fluorescence microscopy. Flow cytometry was performed for LDLR surface expression studies. Uptake of LDL cholesterol was visualized by confocal microscopy. SREBP activation was determined performing Western Blotting. The efficiency of archazolid B/fluvastatin combination was tested by cytotoxicity assays.

RESULTS

Archazolid B led to accumulation of free cholesterol within intracellular compartments and drastic disturbances in cholesterol homeostasis resulting in activation of SREBP-2 (sterol regulatory element-binding protein 2) and up-regulation of target genes including HMGCR (HMG-CoA reductase), the key enzyme of cholesterol biosynthesis. LDLR surface expression was reduced and LDL uptake was completely inhibited after 24h, indicating newly synthesized cholesterol to be the main source of cholesterol in archazolid B treated cells. By combining archazolid B with the HMGCR inhibitor fluvastatin, cholesterol was reduced and cell viability decreased by about 20% compared to archazolid B treatment alone.

CONCLUSIONS

Our study revealed cholesterol biosynthesis as an important resistance mechanism in T24 cells after archazolid B treatment. The combination of archazolid B with statins may be an attractive strategy to potentiate archazolid B induced cell killing by affecting cholesterol biosynthesis.

Diagnostic and treatment implications of psychosis secondary to treatable metabolic disorders in adults: a systematic review

Objective

It is important for psychiatrists to be aware of certain inborn errors of metabolism (IEMs) as these rare disorders can present as psychosis, and because definitive treatments may be available for treating the underlying metabolic cause. A systematic review was conducted to examine IEMs that often present with schizophrenia-like symptoms.

Data sources

Published literature on MEDLINE was assessed regarding diseases of homocysteine metabolism (DHM; cystathionine beta-synthase deficiency [CbS-D] and homocysteinemia due to methyltetrahydrofolate reductase deficiency [MTHFR-D]), urea cycle disorders (UCD), acute porphyria (POR), Wilson disease (WD), cerebrotendinous-xanthomatosis (CTX) and Niemann-Pick disease type C (NP-C).

Study selection

Case reports, case series or reviews with original data regarding psychiatric manifestations and cognitive impairment published between January 1967 and June 2012 were included based on a standardized four-step selection process.

Data extraction

All selected articles were evaluated for descriptions of psychiatric signs (type, severity, natural history and treatment) in addition to key disease features.

Results

A total of 611 records were identified. Information from CbS-D (n = 2), MTHFR-D (n = 3), UCD (n = 8), POR (n = 12), WD (n = 11), CTX (n = 14) and NP-C publications (n = 9) were evaluated. Six non-systematic literature review publications were also included. In general, published reports did not provide explicit descriptions of psychiatric symptoms. The literature search findings are presented with a didactic perspective, showing key features for each disease and psychiatric signs that should trigger psychiatrists to suspect that psychotic symptoms may be secondary to an IEM.

Conclusion

IEMs with a psychiatric presentation and a lack of, or sub-clinical, neurological signs are rare, but should be considered in patients with atypical psychiatric symptoms.

Effects of miglustat on stabilization of neurological disorder in niemann-pick disease type C: Iranian pediatric case series

Niemann-Pick disease type C is a rare neurodegenerative disorder with autosomal recessive inheritance that can be broadly categorized into different forms dependent on age at disease onset: pre-/perinatal, early infantile, late infantile, juvenile, and adolescent/adult. This study was conducted to define the age at onset, clinical manifestations, neuroimaging findings and response to treatment in 21 patients diagnosed with Niemann-Pick disease type C and managed in the neurology departments of hospitals in Tehran, Iran. The effects of miglustat on patient ambulation, fine and gross motor function, swallowing, hearing, speech, seizures, psychomotor development, and ocular movements were evaluated for up to 26 months of treatment. Ambulation, fine and gross motor movements, swallowing, speech, and supranuclear gaze palsy were generally stabilized during therapy, and psychomotor delay appeared to be improved in early- and late-infantile onset patients. However, miglustat had no effect on organomegaly or other systemic manifestations of the disease. Miglustat was well tolerated.

Efficacy of miglustat in Niemann-Pick C disease: a single centre experience

Niemann-Pick disease type C (NPC) is a lysosomal storage disease characterized by progressive neurological degeneration. Miglustat is the first approved specific therapy and its efficacy in stabilizing or slowing disease progression has been demonstrated in previous studies. We evaluated data from 10 NPC patients treated with Miglustat in a single study centre. All disease manifestations were assessed and patients were stratified according to age at onset of neurological symptoms. Neurological data were recorded by using a modified version of the NP-C disability scale; a "composite score" and a "mean annual change" were calculated to evaluate disease progression. We observed a mean annual change of the composite score of 0.04 in our cohort, indicating slower progression of neurological symptoms if compared with the natural history of the disease. The evidence of slower disease evolution in patients treated with Miglustat suits with previous data and here it is also emphasized by the comparison between disease progression in two early-infantile onset patients receiving different Miglustat dosages. Evaluation of the mean annual change for individual subgroups of patients evidenced minor values in juvenile patients, highlighting better response in such class of patients. Among individual neurological parameters, swallowing showed the minor mean annual change (0.02), indicating better response to therapy. We underline the importance of using a standardized disability scale to quantify and compare neurological features and their evolution over time.

Psychiatric manifestations in cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare and severe, but treatable, inborn disorder of bile acid biosynthesis and sterol storage with autosomal recessive inheritance and variable clinical presentation. CTX treatment consists of chenodeoxycholic acid and must be started as early as possible to prevent permanent disability. Psychiatric manifestations are rare and non-specific, and often lead to significant diagnostic and treatment delay. Therefore, better recognition of the gamut of psychiatric manifestations in CTX can diminish the risk of misdiagnosis and irreversible neurological deterioration. We hereby describe the psychiatric features in CTX. A complete review of all published cases of CTX in the medical literature was undertaken and the case reports with psychiatric presentation were collected and analyzed. We also describe the psychiatric features in relation to the neurological semeiology in six patients with CTX diagnosed at the La Salpêtrière Hospital. We conclude that psychiatric manifestations in CTX follow a bimodal/bitemporal pattern, appearing early in the disease course in the form of a behavioral/personality disorder associated with learning difficulties or mental retardation, or manifesting in advanced disease in the setting of dementia as rich neuropsychiatric syndromes, such as frontal, orbitofrontal or frontotemporal syndromes of cortico-subcortical dementia encompassing behavioral/personality disturbance, affective/mood disorders or psychotic disorders. Behavioral/personality disturbance in childhood or adolescence, especially when accompanied by learning difficulties, should therefore lead to further investigation to exclude CTX, as early diagnosis and treatment is critical for prognosis.

Niemann-Pick disease type C clinical database: cognitive and coordination deficits are early disease indicators

Background

The neurodegenerative lysosomal storage disorder Niemann-Pick disease type C (NP-C) is characterized by a broad clinical variability involving neurological, psychiatric and systemic signs. Diverse patterns of disease manifestation and progression considerably delay its diagnosis. Here we introduce the NP-C clinical database (NPC-cdb) to systematically obtain, store and analyze diagnostic and clinical findings in patients with NP-C. We apply NPC-cdb to study NP-C temporal expression in a large German-Swiss patient cohort.

Methods

Current and past medical history was systematically acquired from 42 patients using tailored questionnaires. Manifestation of 72 distinct neuropsychiatric signs was modeled over the course of disease. The sequence of disease progression was re-constructed by a novel clinical outcome scale (NPC-cdb score).

Results

The efficiency of current clinical diagnostic standards negatively correlates with duration of disease (p<3.9x10^-4), suggesting insufficient sensitivity in patients early in the disease process. Neurological signs considered as typical for NP-C were frequent (e.g., cognitive impairment 86%, ataxia 79%, vertical supranuclear gaze palsy 76%) and their presence co-occurred with accelerated diagnosis. However, less specific neuropsychiatric signs were reported to arise considerably more early in the disease process (e.g., clumsiness -4.9±1.1 y before diagnosis). Most patients showed a steady disease progression that correlated with age at neurological onset. However, a distinct subcohort (n=6) with initially steadily progressing disease later showed a 2.9-fold accelerated progression that was associated with the onset of seizures (p<7x10^-4), suggesting seizures as predictive for a poor prognosis.

Conclusions

Considering early, but less specific neuropsychiatric signs may accelerate the path to diagnosing NP-C in a patient.

Disease and patient characteristics in NP-C patients: findings from an international disease registry

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare neurovisceral disease characterized by progressive neurodegeneration and premature death. We report data recorded at enrolment in an ongoing international NP-C registry initiated in September 2009 to describe disease natural history, clinical course and treatment experience of NP-C patients in clinical practice settings.

METHODS

The NPC Registry is a prospective observational cohort study. Participating sites are encouraged to evaluate all consecutive patients with a confirmed diagnosis of NP-C, regardless of their treatment status. All patients undergo clinical assessments and medical care as determined by their physicians. Data are collected through a secure internet-based data collection system.

RESULTS

As of 19th March, 2012, 163 patients have been enrolled in centres across 14 European countries, Australia, Brazil and Canada. The mean (SD) age at enrolment was 19.6 (13.0) years. In general there was a long lag time between the mean (SD) age at neurological onset (10.9 (9.8) years) and age at diagnosis (15.0 (12.2) years). Among all enrolled patients, 107 were diagnosed based on combined genetic testing and filipin staining. Sixteen (11%) out of 145 patients with available age-at-neurological-onset data had early-infantile neurological onset, 45 (31%) had late-infantile onset; 45 (31%) had juvenile onset and 39 (27%) had adolescent/adult onset. The frequencies of neonatal jaundice, hepatomegaly and/or splenomegaly during infancy were greatest among early-infantile patients, and decreased with increasing age at neurological onset. The most frequent neurological manifestations were: ataxia (70%), vertical supranuclear gaze palsy (VSGP; 70%), dysarthria (66%), cognitive impairment (62%), dysphagia (52%). There were no notable differences in composite NP-C disability scores between age-at-neurological-onset groups. Miglustat therapy at enrolment was recorded in 117/163 (72%) patients.

CONCLUSIONS

Approximately two-thirds of this NP-C cohort had infantile or juvenile onset of neurological manifestations, while the remaining third presented in adolescence or adulthood. While systemic symptoms were most common among patients with early-childhood onset disease, they were also common among patients with adolescent/adult onset. The profiles of neurological manifestations in this Registry were in line with previous publications.

Long-term efficacy of miglustat in paediatric patients with Niemann-Pick disease type C

Niemann-Pick disease type C (NP-C) is a rare inherited neurovisceral disease characterized by progressive neurological manifestations. Oral miglustat was first approved for the treatment of children and adults with NP-C in Europe in 2009. There are still relatively few published data on the long-term efficacy and safety of miglustat in patients with NP-C in clinical practice. We report the effects of up to 6 years of treatment with miglustat 100 mg t.i.d. in five children. Overall, 3/5 patients displayed progressive dysphagia before starting miglustat, and 4/5 showed marked cognitive and/or motor impairment. The mean age at treatment start was 11.6 years, and the median (range) duration of therapy so far is 4 (4.1 to 6.1) years. No treatment dose alterations were required, but therapy was interrupted for 1-3 months at least once in all patients due to supply issues. Swallowing function was stabilised during miglustat therapy, with no significant increase in Han dysphagia scale or aspiration-penetration index scores among four evaluable patients (p > 0.05). Scores on the mini-mental state examination indicated an improvement in cognitive function during the first 3-6 months of miglustat therapy, followed by stabilisation up to 5 years. Ambulatory function remained stable for at least the first 2 years of treatment in most patients, but there was a trend towards deterioration thereafter, possibly related to treatment interruptions. The safety/tolerability profile of miglustat was similar to previous clinical studies, although reports of gastrointestinal disturbances were rare. Overall, miglustat appeared to stabilise key parameters of neurological disease progression.

Niemann-pick disease type C: implications for sedation and anesthesia for diagnostic procedures

Niemann-Pick disease type C, an autosomal recessive lysosomal storage disorder, can present with severe visceral and neurologic involvement and is associated with a significant decrease in life expectancy. As little is known about anesthetic considerations of this disease, we examined the perianesthetic course of patients with Niemann-Pick disease type C. Thirty-two patients with Niemann-Pick disease type C, median age 6.9 years (1.8-33 years), underwent 64 general anesthetics for diagnostic procedures. Perianesthetic morbidity included need for tracheal reintubation, pneumonitis, hypothermia, and seizure. Therefore, Niemann-Pick disease type C-associated neurologic and visceral involvement might have anesthetic implications that neurologists and pediatricians should be aware of and consider discussing with parents, guardians, and the patient's care team when procedures requiring anesthesia are planned. Furthermore, it is important for delivery of safe anesthesia that there is communication among care team members so that all involved understand the disease manifestation spectrum.

Use of miglustat in a child with late-infantile-onset Niemann-Pick disease type C and frequent seizures: a case report

Introduction

Niemann-Pick disease type C is a rare genetic lysosomal storage disease associated with impaired intracellular lipid trafficking and a range of progressive neurological manifestations. The influence of seizure activity on disease course and response to miglustat therapy is not currently clear.

Case presentation

Niemann-Pick disease type C homozygous for NPC1 mutation p.S940L [c. 2819 C>T] was diagnosed in a four-and-a-half-year-old Norwegian Caucasian girl. The patient, who died at eight years and seven months of age, had a history of prolonged neonatal jaundice and subsequently displayed progressive neurological manifestations that started with delayed speech, ataxia, and gelastic cataplexy. A regimen of 100mg of miglustat three times a day was initiated when she was four years and 11 months old. She showed decreased neurological deterioration during about three and a half years of treatment. However, she displayed periods of distinct worsening that coincided with frequent epileptic seizures. Anti-epileptic therapy reduced seizure frequency and severity and allowed re-stabilization of her neurological function. Prior to her death, which was possibly due to acute cardiac arrest, seizure activity was well controlled.

Conclusions

Miglustat delayed the expected deterioration of neurological function in this patient with p.S940L-homozygous late-infantile-onset Niemann-Pick disease type C and provided important quality-of-life benefits. This case demonstrates the importance of effective seizure control therapy in achieving and maintaining neurological stabilization in Niemann-Pick disease type C.

Dysphagia as a risk factor for mortality in Niemann-Pick disease type C: systematic literature review and evidence from studies with miglustat

Niemann-Pick disease type C (NP-C) is a rare neurovisceral disease characterised by progressive neurological deterioration and premature death, and has an estimated birth incidence of 1:120,000. Mutations in the NPC1 gene (in 95% of cases) and the NPC2 gene (in approximately 4% of cases) give rise to impaired intracellular lipid metabolism in a number of tissues, including the brain. Typical neurological manifestations include vertical supranuclear gaze palsy, saccadic eye movement abnormalities, cerebellar ataxia, dystonia, dysmetria, dysphagia and dysarthria. Oropharyngeal dysphagia can be particularly problematic as it can often lead to food or fluid aspiration and subsequent pneumonia. Epidemiological data suggest that bronchopneumonia subsequent to food or fluid aspiration is a major cause of mortality in NP-C and other neurodegenerative disorders. These findings indicate that a therapy capable of improving or stabilising swallowing function might reduce the risk of aspiration pneumonia, and could have a positive impact on patient survival. Miglustat, currently the only approved disease-specific therapy for NP-C in children and adults, has been shown to stabilise key neurological manifestations in NP-C, including dysphagia. In this article we present findings from a systematic literature review of published data on bronchopneumonia/aspiration pneumonia as a cause of death, and on the occurrence of dysphagia in NP-C and other neurodegenerative diseases. We then examine the potential links between dysphagia, aspiration, pneumonia and mortality with a view to assessing the possible effect of miglustat on patient lifespan.

Early miglustat therapy in infantile Niemann-Pick disease type C

Niemann-Pick disease type C is a rare inherited cholesterol trafficking disorder, where impaired intracellular lipid transport leads to storage of unesterified cholesterol and glycosphingolipids in many tissues, including the brain. Substrate reduction therapy with miglustat, an iminosugar that inhibits glycosphingolipid synthesis, was proposed to treat Niemann-Pick disease type C, based on evidence of slower disease progression and prolonged survival in animal models. Miglustat was subsequently approved in Europe to treat progressive neurologic manifestations in both children and adults in early 2009, based on clinical study data. We report on the early treatment of two pediatric Niemann-Pick type C patients with miglustat. Patient 1, a 7.5-year-old girl with early-infantile onset, began receiving miglustat at age 7 months. Patient 2, the brother of a girl diagnosed with late-infantile onset Niemann-Pick type C, began receiving miglustat at age 19 months, when he was asymptomatic for neurologic disease. After 7 and 5 years of miglustat therapy, respectively, both patients remain free of neurologic manifestations. These findings suggest that miglustat may be more effective if used to prevent, rather than treat, neurologic manifestations in infantile-onset Niemann-Pick type C.

Recommendations for the diagnosis and management of Niemann-Pick disease type C: an update

Niemann-Pick disease type C (NP-C) is a rare inherited neurovisceral disease caused by mutations in either the NPC1 (in 95% of cases) or the NPC2 gene (in around 5% of cases), which lead to impaired intracellular lipid trafficking and accumulation of cholesterol and glycosphingolipids in the brain and other tissues. Characteristic neurological manifestations of NP-C include saccadic eye movement (SEM) abnormalities or vertical supranuclear gaze palsy (VSGP), cerebellar signs (ataxia, dystonia/dysmetria, dysarthria and dysphagia) and gelastic cataplexy. Epileptic seizures are also common in affected patients. Typically, neurological disease onset occurs during childhood, although an increasing number of cases are being detected and diagnosed during adulthood based on late-onset neurological signs and psychiatric manifestations. Categorization of patients according to age at onset of neurological manifestations (i.e. early-infantile, late-infantile, juvenile and adolescent/adult-onset) can be useful for the evaluation of disease course and treatment responses. The first international guidelines for the clinical management of NP-C in children and adults were published in 2009. Since that time a significant amount of data regarding the epidemiology, detection/diagnosis, and treatment of NP-C has been published. Here, we report points of consensus among experts in the diagnosis and treatment of NP-C based on a follow-up meeting in Paris, France in September 2011. This article serves as an update to the original guidelines providing, among other things, further information on detection/diagnostic methods, potential new methods of monitoring disease progression, and therapy. Treatment goals and the application of disease-specific therapy with miglustat are also re-evaluated.

Miglustat therapy in the French cohort of paediatric patients with Niemann-Pick disease type C

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare neurovisceral lysosomal lipid storage disease characterized by progressive neurological deterioration. Published data on the use of miglustat in paediatric patients in clinical practice settings are limited. We report findings from a prospective open-label study in the French paediatric NP-C cohort.

METHODS

Data on all paediatric NP-C patients treated with miglustat in France between October 2006 and December 2010 were compiled. All patients had a confirmed diagnosis of NP-C, and received miglustat therapy according to manufacturer's recommendations. Pre-treatment and follow-up assessments were conducted according to a standardized protocol.

RESULTS

Twenty children were enrolled; 19 had NPC1 gene mutations and 1 had NPC2 gene mutations. The median age at diagnosis was 1.5 years, and the median age at miglustat initiation was 6.0 years. Eight NPC1 patients had the early-infantile, eight had the late-infantile, and three had the juvenile-onset forms of NP-C. A history of hepatosplenomegaly and/or other cholestatic symptoms was recorded in all 8 early-infantile onset patients, 3/8 late-infantile patients, and 1/3 juvenile onset patients. Brain imaging indicated white matter abnormalities in most patients. The median (range) duration of miglustat therapy was 1.3 (0.6-2.3) years in early-infantile, 1.0 (0.8-5.0) year in late-infantile, and 1.0 (0.6-2.5) year in juvenile onset patients. NP-C disability scale scores indicated either stabilization or improvement of neurological manifestations in 1/8, 6/8, and 1/3 NPC1 patients in these subgroups, respectively. There were no correlations between brain imaging findings and disease course. Mild-to-moderate gastrointestinal disturbances were frequent during the first 3 months of miglustat therapy, but were easily managed with dietary modifications and/or anti-propulsive medication.

CONCLUSIONS

Miglustat can improve or stabilize neurological manifestations in paediatric patients with the late-infantile and juvenile-onset forms of NP-C. Among early-infantile onset patients, a shorter delay between neurological disease onset and miglustat initiation was associated with an initial better therapeutic outcome in one patient, but miglustat did not seem to modify overall disease course in this subgroup. More experience is required with long-term miglustat therapy in early-infantile onset patients treated from the very beginning of neurological manifestations.

Altered vitamin E status in Niemann-Pick type C disease

Vitamin E (α-tocopherol) is the major lipid-soluble antioxidant in many species. Niemann-Pick type C (NPC) disease is a lysosomal storage disorder caused by mutations in the NPC1 or NPC2 gene, which regulates lipid transport through the endocytic pathway. NPC disease is characterized by massive intracellular accumulation of unesterified cholesterol and other lipids in lysosomal vesicles. We examined the roles that NPC1/2 proteins play in the intracellular trafficking of tocopherol. Reduction of NPC1 or NPC2 expression or function in cultured cells caused a marked lysosomal accumulation of vitamin E in cultured cells. In vivo, tocopherol significantly accumulated in murine Npc1-null and Npc2-null livers, Npc2-null cerebella, and Npc1-null cerebral cortices. Plasma tocopherol levels were within the normal range in Npc1-null and Npc2-null mice, and in plasma samples from human NPC patients. The binding affinity of tocopherol to the purified sterol-binding domain of NPC1 and to purified NPC2 was significantly weaker than that of cholesterol (measurements kindly performed by R. Infante, University of Texas Southwestern Medical Center, Dallas, TX). Taken together, our observations indicate that functionality of NPC1/2 proteins is necessary for proper bioavailability of vitamin E and that the NPC pathology might involve tissue-specific perturbations of vitamin E status.

[Niemann-Pick type C disease: clinical presentations in pediatric patients]

Niemann-Pick type C disease (NPC) is a rare, neurovisceral, autosomic recessive, lysosomal lipid storage disorder associated with impaired intracellular lipid trafficking leading to accumulation of cholesterol and glycosphingolipids in the brain, the liver, the spleen and also the lung. NPC has a very heterogenous clinical presentation from perinatal period to adulthood. The perinatal presentation is visceral. In the early-infantile, late-infantile and juvenile period, a wide range of aspecific and progressive neurologic symptoms varies according to the age at onset, but four signs have a great diagnostic value : prolonged neonatal cholestasis, splenomegaly, cataplexy and vertical supranuclear gaze palsy. The diagnosis confirmation requires a fibroblast culture and molecular genetic testing of NPC1 and NPC2 genes. The recent approval of a specific treatment, reducing neurological disease progression, makes essential an early diagnosis of NPC.

Niemann-Pick disease type C

Niemann-Pick C disease (NP-C) is a neurovisceral atypical lysosomal lipid storage disorder with an estimated minimal incidence of 1/120 000 live births. The broad clinical spectrum ranges from a neonatal rapidly fatal disorder to an adult-onset chronic neurodegenerative disease. The neurological involvement defines the disease severity in most patients but is typically preceded by systemic signs (cholestatic jaundice in the neonatal period or isolated spleno- or hepatosplenomegaly in infancy or childhood). The first neurological symptoms vary with age of onset: delay in developmental motor milestones (early infantile period), gait problems, falls, clumsiness, cataplexy, school problems (late infantile and juvenile period), and ataxia not unfrequently following initial psychiatric disturbances (adult form). The most characteristic sign is vertical supranuclear gaze palsy. The neurological disorder consists mainly of cerebellar ataxia, dysarthria, dysphagia, and progressive dementia. Cataplexy, seizures and dystonia are other common features. NP-C is transmitted in an autosomal recessive manner and is caused by mutations of either the NPC1 (95% of families) or the NPC2 genes. The exact functions of the NPC1 and NPC2 proteins are still unclear. NP-C is currently described as a cellular cholesterol trafficking defect but in the brain, the prominently stored lipids are gangliosides. Clinical examination should include comprehensive neurological and ophthalmological evaluations. The primary laboratory diagnosis requires living skin fibroblasts to demonstrate accumulation of unesterified cholesterol in perinuclear vesicles (lysosomes) after staining with filipin. Pronounced abnormalities are observed in about 80% of the cases, mild to moderate alterations in the remainder ("variant" biochemical phenotype). Genotyping of patients is useful to confirm the diagnosis in the latter patients and essential for future prenatal diagnosis. The differential diagnosis may include other lipidoses; idiopathic neonatal hepatitis and other causes of cholestatic icterus should be considered in neonates, and conditions with cerebellar ataxia, dystonia, cataplexy and supranuclear gaze palsy in older children and adults. Symptomatic management of patients is crucial. A first product, miglustat, has been granted marketing authorization in Europe and several other countries for specific treatment of the neurological manifestations. The prognosis largely correlates with the age at onset of the neurological manifestations.

Defective cholesterol trafficking in Niemann-Pick C-deficient cells

Pathways of intracellular cholesterol trafficking are poorly understood at the molecular level. Mutations in Niemann-Pick C (NPC) proteins, NPC1 and NPC2, however, have led to insights into the mechanism by which endocytosed cholesterol is exported from late endosomes/lysosomes (LE/L). Mutations in NPC1, a multi-spanning membrane protein of LE/L, or mutations in NPC2, a soluble luminal protein of LE/L, cause the neurodegenerative disorder NPC disease. This review focuses on data supporting a model in which movement of cholesterol out of LE/L is mediated by the sequential action of the two NPC proteins. We also discuss potential therapies for NPC disease, including evidence that treatment of NPC-deficient mice with the cholesterol-binding compound, cyclodextrin, markedly attenuates neurodegeneration, and increases life-span, of NPC1-deficient mice.

Clinical experience with miglustat therapy in pediatric patients with Niemann-Pick disease type C: a case series

Niemann-Pick disease type C (NP-C) is an inherited neurovisceral lysosomal lipid storage disease characterized by progressive neurological deterioration. Different clinical forms have been defined based on patient age at onset: perinatal, early-infantile (EI), late-infantile (Li), juvenile and adult. We evaluated the efficacy and tolerability of miglustat in 16 symptomatic NP-C patients, with comparative reference to one neurologically asymptomatic, untreated patient. All patients were categorized according to age at neurological disease onset, and were assessed using a standardized clinical assessment protocol: disability and cognitive function scales, positron emission tomography (PET), and biochemical markers. PET and disability scale evaluations indicated that cerebral hypometabolism and neurological symptoms were stabilized during treatment in juvenile-onset NP-C patients. EI and Li NP-C patients, who had higher disease severity at baseline (treatment start), showed increased disability scores and progressive cerebral hypometabolism during follow up. Similarly, while cognitive scale scores remained relatively stable in patients with juvenile NP-C, cognition deteriorated in EI and Li patients. Plasma chitotriosidase (ChT) activity was lower in the juvenile NP-C subgroup than in EI and Li patients, and generally increased in patients who discontinued treatment. Plasma CCL18/PARC and ChT activities indicated greater macrophagic activity in EI and Li patients versus juveniles. Miglustat was generally well tolerated; frequent adverse events included diarrhea and flatulence, which were managed effectively by dietary modification and loperamide. Overall, miglustat appeared to stabilize neurological status in juvenile-onset NP-C patients, but therapeutic benefits appeared smaller among younger patients who were at a more advanced stage of disease at baseline.

Miglustat in adult and juvenile patients with Niemann-Pick disease type C: long-term data from a clinical trial

A randomized, controlled trial of miglustat indicated that miglustat (Zavesca) stabilized neurological disease over 12 months in adult and juvenile patients with Niemann-Pick disease type C (NP-C). We report data from a non-controlled, open-label extension to this initial randomized trial. All patients completing the randomized trial were allowed to continue treatment in a 12-month, non-controlled open-label extension. Those completing 12 months of extension therapy could continue further on miglustat in a 'continued extension' phase. From a total of 29 patients in the randomized phase (mean [+/-SD] age 24.6+/-9.1 ears; 52% female), 21 completed 12 months of therapy with miglustat (17 of whom received miglustat in the initial randomized phase, and four in the extension phase), and 15 patients (all from the miglustat-randomized group) completed 24 months on miglustat. Mean horizontal saccadic eye movement velocity (HSEM-alpha) indicated improvement in the 12-month miglustat group, and stabilization in the 24-month group; swallowing was improved or stable in 86% and in up to 93%, respectively. Ambulation was stabilized in both the 12- and 24-month groups. In an exploratory disease stability analysis of prospective data on key parameters of disease progression (HSEM-alpha, swallowing, ambulation and cognition), 13/19 (68%) patients receiving >or= 12 months' miglustat therapy had stable disease. Among all patients receiving >or= 1 dose of miglustat (n=28), the most frequent adverse events were diarrhoea, weight decrease, flatulence and tremor. Overall, these data suggest that long-term miglustat therapy stabilizes neurological disease and is well tolerated in adult and juvenile patients with NP-C.

New therapies in the management of Niemann-Pick type C disease: clinical utility of miglustat

Niemann-Pick disease type C (NP-C) is an autosomal recessive disorder characterized by progressive neurological deterioration leading to premature death. The disease is caused by mutations in one of two genes, NPC1 or NPC2, leading to impaired intracellular lipid transport and build-up of lipids in various tissues, particularly the brain. Miglustat (Zavesca(R)), a reversible inhibitor of glycosphingolipid synthesis, has recently been authorized in the European Union, Brazil and South Korea for the treatment of progressive neurological symptoms in adult and pediatric patients, and represents the first specific treatment for NP-C. Here we review current data on the pharmacology, efficacy, safety and tolerability of miglustat in patients with NP-C, based on findings from a prospective clinical trial, preclinical and retrospective studies, and case reports. Findings demonstrated clinically relevant beneficial effects of miglustat on neurological disease progression in adult, juvenile and pediatric patients with NP-C, particularly those diagnosed in late childhood (6-11 years) and in juveniles and adults (12 years and older), compared with those diagnosed in early childhood (younger than 6 years). Miglustat therapy was well-tolerated in all age groups. With the approval of miglustat, treatment of patients with NP-C can now be aimed toward stabilizing neurological disease, which is likely the best attainable therapeutic goal for this disorder.