Cost of illness associated with Niemann-Pick disease type C in the UK

Overview of clinical, molecular, and therapeutic features of Niemann-Pick disease (types A, B, and C): Focus on therapeutic approaches

Niemann-Pick disease (NPD) is another type of metabolic disorder that is classified as lysosomal storage diseases (LSDs). The main cause of the disease is mutation in the SMPD1 (type A and B) or NPC1 or NPC2 (type C) genes, which lead to the accumulation of lipid substrates in the lysosomes of the liver, brain, spleen, lung, and bone marrow cells. This is followed by multiple cell damage, dysfunction of lysosomes, and finally dysfunction of body organs. So far, about 346, 575, and 30 mutations have been reported in SMPD1, NPC1, and NPC2 genes, respectively. Depending on the type of mutation and the clinical symptoms of the disease, the treatment will be different. The general aim of the current study is to review the clinical and molecular characteristics of patients with NPD and study various treatment methods for this disease with a focus on gene therapy approaches.

The collective burden of childhood dementia: a scoping review

Childhood dementia is a devastating and under-recognized group of disorders with a high level of unmet need. Typically monogenic in origin, this collective of individual neurodegenerative conditions are defined by a progressive impairment of neurocognitive function, presenting in childhood and adolescence. This scoping review aims to clarify definitions and conceptual boundaries of childhood dementia and quantify the collective disease burden. A literature review identified conditions that met the case definition. An expert clinical working group reviewed and ratified inclusion. Epidemiological data were extracted from published literature and collective burden modelled. One hundred and seventy genetic childhood dementia disorders were identified. Of these, 25 were analysed separately as treatable conditions. Collectively, currently untreatable childhood dementia was estimated to have an incidence of 34.5 per 100 000 (1 in 2900 births), median life expectancy of 9 years and prevalence of 5.3 per 100 000 persons. The estimated number of premature deaths per year is similar to childhood cancer (0-14 years) and approximately 70% of those deaths will be prior to adulthood. An additional 49.8 per 100 000 births are attributable to treatable conditions that would cause childhood dementia if not diagnosed early and stringently treated. A relational database of the childhood dementia disorders has been created and will be continually updated as new disorders are identified (https://knowledgebase.childhooddementia.org/). We present the first comprehensive overview of monogenic childhood dementia conditions and their collective epidemiology. Unifying these conditions, with consistent language and definitions, reinforces motivation to advance therapeutic development and health service supports for this significantly disadvantaged group of children and their families.

Cost-effectiveness of miglustat versus symptomatic therapy of Niemann-Pick disease type C

BACKGROUND

Niemann-Pick disease type C (NP-C) is a progressive neurodegenerative disorder with early infantile (< 2 years), late infantile (2-6 years), juvenile (7-15 years) and adolescent (> 15 years) onset. The mainstay of therapy for NP-C patients with neurological symptoms is miglustat, a drug that may modify the course of the disease.

AIM

Our aim was to evaluate the cost-effectiveness of miglustat in comparison to symptomatic therapy in patients with NP-C in the socio-economic settings of the Republic of Serbia, an upper-middle-income European economy.

METHOD

The perspective of the Serbian Republic Health Insurance Fund was chosen for this study, and the time horizon was eighty years. The main outcomes of the study were quality-adjusted life years gained with miglustat and comparator, and direct costs of treatment. The study was conducted through the generation and simulation of the Discrete-Event Simulation model. The model results were obtained after Monte Carlo microsimulation of a sample with 1000 virtual patients.

RESULTS

Treatment with miglustat was not cost-effective when compared with symptomatic therapy and was associated with negative values of net monetary benefit regardless of the onset of neurological manifestations (- 110,447,627.00 ± 701,614.00 RSD, - 343,871,695.00 ± 2,577,441.00 RSD, - 1,397,908,502.00 ± 23,084,235.00 RSD and - 2,953,680,879.00 ± 33,297,412.00 RSD) for early infantile, late infantile, juvenile and adolescent cohorts, respectively).

CONCLUSION

When traditional pharmacoeconomic evaluation is employed, miglustat is not a cost-effective option in comparison to symptomatic therapy for the treatment of NP-C. However, given the proven efficacy of miglustat, there is a need to find ways to make this drug available to all patients with NP-C.

Health insurance literacy and health services access barriers in Niemann-Pick disease: the patient and caregiver voice

Background

Major challenges to health care access include low health insurance literacy, prohibitive costs, and insurance barriers. Niemann–Pick disease (NPD), comprising acid sphingomyelinase deficiency (ASMD) and Niemann–Pick type C (NPC), is a group of rare, autosomal recessive, highly heterogeneous, neurovisceral, life-threatening, relentlessly progressive lysosomal disorders. Patients experience debilitating systemic and neurological symptoms and substantial emotional and financial stress. Currently, these multifaceted disorders are managed symptomatically as there are no approved therapies. Given the considerable disease burden of NPD, timely access to quality health care is paramount for improving outcomes in these life-threatening disorders. Understanding health insurance literacy and access challenges among patients with NPD and their caregivers is a first step to overcoming treatment barriers.

Results

Patients from the Niemann–Pick community participated in a health insurance literacy survey and follow-up telephone interviews on perceived access challenges. Of the 79 respondents who completed the survey, 67 participated in interviews. All respondents had stable health insurance coverage. However, 61% of respondents were unaware of Medicaid waivers and did not avail of them. Overall, 50% of respondents with childhood onset NPC selected Medicaid/Medicare and private insurance; 35% utilized Medicaid waivers. Most respondents with ASMD had private insurance only. Although the Niemann–Pick community demonstrated greater health insurance literacy than the general population, knowledge gaps exist in calculating insurance coverage, out-of-pocket maximums, and defining a formulary. The most frequently cited access burden was the process of obtaining medical care and services. Among respondents with ASMD, the greatest access burden was fear of unavailability of or access to medications and treatment. Access challenges adversely impacted patients’ mental health and exacerbated physical symptoms. Delays and denials in obtaining essential medication, equipment, and services contributed to disease progression. Caregivers faced burnout and often questioned the utility of their advocacy.

Conclusions

This study identified knowledge gaps in health insurance literacy and challenges to access medication and health care services among individuals impacted by NPD. Patients and caregivers need the knowledge and skills to navigate a complicated health care system, understand their rights to medication and services and, ultimately, benefit from improved outcomes, especially in a post–drug approval era.

Healthcare resource utilisation and medical costs for children with interstitial lung diseases (chILD) in Europe

BACKGROUND

No data on healthcare utilisation and associated costs for the many rare entities of children's interstitial lung diseases (chILD) exist. This paper portrays healthcare utilisation structures among individuals with chILD, provides a pan-European estimate of a 3-month interval per-capita costs and delineates crucial cost drivers.

METHODS

Based on longitudinal healthcare resource utilisation pattern of 445 children included in the Kids Lung Register diagnosed with chILD across 10 European countries, we delineated direct medical and non-medical costs of care per 3-month interval. Country-specific utilisation patterns were assessed with a children-tailored modification of the validated FIMA questionnaire and valued by German unit costs. Costs of care and their drivers were subsequently identified via gamma-distributed generalised linear regression models.

RESULTS

During the 3 months prior to inclusion into the registry (baseline), the rate of hospital admissions and inpatient days was high. Unadjusted direct medical per capita costs (€19 818) exceeded indirect (€1 907) and direct non-medical costs (€1 125) by far. Country-specific total costs ranged from €8 713 in Italy to €28 788 in Poland. Highest expenses were caused by the disease categories 'diffuse parenchymal lung disease (DPLD)-diffuse developmental disorders' (€45 536) and 'DPLD-unclear in the non-neonate' (€47 011). During a follow-up time of up to 5 years, direct medical costs dropped, whereas indirect costs and non-medical costs remained stable.

CONCLUSIONS

This is the first prospective, longitudinal study analysing healthcare resource utilisation and costs for chILD across different European countries. Our results indicate that chILD is associated with high utilisation of healthcare services, placing a substantial economic burden on health systems.

Cost-of-illness studies in rare diseases: a scoping review

Objective

The aim of this scoping review was to overview the cost-of-illness studies conducted in rare diseases.

Methods

We searched papers published in English in PubMed from January 2007 to December 2018. We selected cost-of-illness studies on rare diseases defined as those with prevalence lower than 5 per 10,000 cases. Studies were selected by one researcher and verified by a second researcher. Methodological characteristics were extracted to develop a narrative synthesis.

Results

We included 63 cost-of-illness studies on 42 rare diseases conducted in 25 countries, and 9 systematic reviews. Most studies (94%) adopted a prevalence-based estimation, where the predominant design was cross-sectional with a bottom-up approach. Only four studies adopted an incidence-based estimation. Most studies used questionnaires to patients or caregivers to collect resource utilisation data (67%) although an important number of studies used databases or registries as a source of data (48%). Costs of lost productivity, non-medical costs and informal care costs were included in 68%, 60% and 43% of studies, respectively.

Conclusion

This review found a paucity of cost-of-illness studies in rare diseases. However, the analysis shows that the cost-of-illness studies of rare diseases are feasible, although the main issue is the lack of primary and/or aggregated data that often prevents a reliable estimation of the economic burden.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01815-3.

Cost-of-illness studies in rare diseases: a scoping review

OBJECTIVE

The aim of this scoping review was to overview the cost-of-illness studies conducted in rare diseases.

METHODS

We searched papers published in English in PubMed from January 2007 to December 2018. We selected cost-of-illness studies on rare diseases defined as those with prevalence lower than 5 per 10,000 cases. Studies were selected by one researcher and verified by a second researcher. Methodological characteristics were extracted to develop a narrative synthesis.

RESULTS

We included 63 cost-of-illness studies on 42 rare diseases conducted in 25 countries, and 9 systematic reviews. Most studies (94%) adopted a prevalence-based estimation, where the predominant design was cross-sectional with a bottom-up approach. Only four studies adopted an incidence-based estimation. Most studies used questionnaires to patients or caregivers to collect resource utilisation data (67%) although an important number of studies used databases or registries as a source of data (48%). Costs of lost productivity, non-medical costs and informal care costs were included in 68%, 60% and 43% of studies, respectively.

CONCLUSION

This review found a paucity of cost-of-illness studies in rare diseases. However, the analysis shows that the cost-of-illness studies of rare diseases are feasible, although the main issue is the lack of primary and/or aggregated data that often prevents a reliable estimation of the economic burden.

Social Economic Costs, Health-Related Quality of Life and Disability in Patients with Cri Du Chat Syndrome

Background: Cri du Chat syndrome (CdC) is a rare disease caused by the deletion on the short arm of the chromosome 5, with an incidence of 1:15,000 to 1:50,000 live-born infants. No study at international level has assessed the costs, Quality of Life (QoL) and Disability through standardized quantitative tools. The aim is to estimate economic costs related to CdC from a societal perspective, to assess the QoL and Disability in patients with CdC along with their caregivers in Italy. Methods: A cross-sectional study of patients with Cri du Chat in Italy was carried out. A cost of illness approach from a societal perspective was used to estimate cost, and a micro-costing method was adopted. The QoL was measured with EuroQol 5-domain (EQ-5D) questionnaire and Disability by using World Health Organization Disability Assessment Schedule 36 item (WHODAS 2.0). Results: A total of 76 questionnaires were collected from caregivers taking care of 40 adult patients and 36 minor patients. All patients need a carer and the principal caregiver is commonly informal carer or a family member (93%). The EQ-5D VAS score for patients is 65.5 (SD = 22.4) out of 100; while the most important compromised areas of QoL are usual activities and self-care. The overall WHODAS 2.0 score is 65% (0 = no disability; 100 = full disability). The average annual cost of a patient with Cri du Chat in our population is €87,856.24; the main cost item of patients with Cri du Chat syndrome is informal care (i.e., €76,981.69 yearly) since it constitutes the 87% of total costs. Results highlight the burden of CdC in terms of its impact on QoL and Disability for patients and caregivers in Italy, with a score much lower than that of general population. The disease is associated with considerable costs of informal care. Conclusions: Cri du Chat syndrome was found to be linked with a significant socioeconomic impact which is dominated by direct non-healthcare informal costs.

A cost of illness study evaluating the burden of Wolfram syndrome in the United Kingdom

Background

Wolfram syndrome is a rare genetic, progressive, neurodegenerative disorder characterised by childhood-onset diabetes mellitus, diabetes insipidus, optic atrophy and deafness. To date, the economic burden of Wolfram syndrome has not been well-studied or reported. The aim of this study was to evaluate the cost of illness (COI) of all people with Wolfram syndrome in the UK and to identify major determinants of cost from a service provider perspective (National Health Service, NHS).

Methods

A prevalence-based approach was used to model the UK Wolfram syndrome specialist service. Model inputs were informed by a pragmatic literature review and UK reference costs, in conjunction with patient interviews and expert opinion. A deterministic sensitivity analysis (DSA) was run at 10% to identify major cost drivers.

Results

The total COI of all people with Wolfram syndrome to the NHS was £1,055,899 per year, with an average annual cost per person with Wolfram syndrome of £16,498. Costs associated with diabetes mellitus care, late-stage diabetes mellitus complications and hearing impairment contributed most to the COI (18.9, 21.4 and 15.8% of the COI, respectively). The DSA identified costs associated with hearing impairment, diabetes mellitus care and end-stage renal disease (a diabetes mellitus complication) as major model drivers.

Conclusions

The annual cost of Wolfram syndrome to the NHS was found to be substantial, with areas of potential cost savings identified, such as diabetes mellitus management. This model provides crucial information to facilitate economic evaluation of prospective therapies for this disease.

Ebola in the Netherlands, 2014-2015: costs of preparedness and response

The recent epidemic of Ebola virus disease (EVD) resulted in countries worldwide to prepare for the possibility of having an EVD patient. In this study, we estimate the costs of Ebola preparedness and response borne by the Dutch health system. An activity-based costing method was used, in which the cost of staff time spent in preparedness and response activities was calculated based on a time-recording system and interviews with key professionals at the healthcare organizations involved. In addition, the organizations provided cost information on patient days of hospitalization, laboratory tests, personal protective equipment (PPE), as well as the additional cleaning and disinfection required. The estimated total costs averaged €12.6 million, ranging from €6.7 to €22.5 million. The main cost drivers were PPE expenditures and preparedness activities of personnel, especially those associated with ambulance services and hospitals. There were 13 possible cases clinically evaluated and one confirmed case admitted to hospital. The estimated total cost of EVD preparedness and response in the Netherlands was substantial. Future costs might be reduced and efficiency increased by designating one ambulance service for transportation and fewer hospitals for the assessment of possible patients with a highly infectious disease of high consequences.

Social/economic costs and health-related quality of life in patients with histiocytosis in Europe

OBJECTIVE

The aim of this study was to determine the economic burden from a societal perspective and the health-related quality of life (HRQOL) of patients with histiocytosis in Europe.

METHODS

We conducted a cross-sectional study of patients with histiocytosis from France, Germany, Italy, Spain, Bulgaria, the UK, and Sweden. Data on demographic characteristics, health resource utilisation, informal care, loss of labour productivity and HRQOL were collected from the questionnaires completed by patients or their caregivers. HRQOL was measured with the EuroQol 5-domain (EQ-5D) questionnaire.

RESULTS

A total of 134 patients (35 France, 32 Germany, 30 Italy, 24 Spain, 7 Bulgaria, 4 UK and 2 Sweden) completed the questionnaire. The average annual costs ranged from € 6832 to € 33,283 between countries, the year of reference being 2012. Estimated direct healthcare costs ranged from € 1698 to € 18,213; direct nonhealthcare costs ranged from € 2936 to € 17,622 and labour productivity losses ranged from € 1 to € 8855. The mean EQ-5D score for adult histiocytosis patients was estimated at between 0.32 and 0.85, and the mean EQ-5D visual analogue scale score was estimated at between 50.00 and 66.50.

CONCLUSION

The main strengths of this study lie in our bottom-up approach to costing and in the evaluation of histiocytosis patients from a broad perspective (societal costs). This type of analysis is very scarce in international literature for rare diseases in comparison with other illnesses. We conclude that histiocytosis patients incur considerable societal costs and experience substantial deterioration in HRQOL.

High level of oxysterols in neonatal cholestasis: a pitfall in analysis of biochemical markers for Niemann-Pick type C disease

Niemann-Pick disease type C (NPC) is a rare lipid storage disorder characterized by progressive neurological deterioration. Diagnosing NPC is challenging as clinical signs and symptoms are variable and non-specific. Two oxysterols, cholestane-3β,5α,6β-triol (triol) and 7-ketocholesterol (7KC), have been proposed as biomarkers for aiding diagnosis of NPC. This study evaluated the use of triol and 7KC as biomarkers in cholestatic neonates with suspected NPC.

Plasma triol and 7KC were analysed as dimethylglycine esters using an liquid chromatography – tandem mass spectrometry (LC-MS/MS) assay in selected neonates with severe cholestasis and suspected NPC (n=7), adults with cholestasis (n=15), patients with confirmed NPC (positive controls; n=11 [one child and 10 adults]), healthy subjects (negative controls; n=40 [20 children and 20 adults]), and cholestatic adults (comparative reference; n=15). The LC-MS/MS method was subjected to a number of tests for accuracy and consistency.

Triol and 7KC levels were substantially and significantly increased in NPC positive patients compared with healthy controls (p<0.001). However, positive results (markedly increased levels of both oxysterols) were identified in 6/7 (86%) neonates with cholestasis. Genetic testing confirmed NPC only in one neonate who had increased triol and 7KC, and increased oxysterol levels among neonates with no identified NPC gene mutations were considered likely due to biliary atresia (BA).

While the potential of oxysterols as NPC biomarkers has been well evaluated in older patient populations (without cholestasis), our data suggest that cholestasis might represent a pitfall in oxysterol measurements intended to aid diagnosis of NPC in affected patients.

Observational cohort study of the natural history of Niemann-Pick disease type C in the UK: a 5-year update from the UK clinical database

BACKGROUND

Niemann-Pick disease type C (NP-C) is a rare neurovisceral lipid storage disorder characterised by progressive, disabling neurological symptoms and premature death in most patients. During the last decade, national cohort studies have accrued a great deal of data on the symptomatology and natural history of NP-C.

METHODS

In an observational cohort study, we present a substantial update based on the clinical presentation and follow-up of all known UK-based patients with a confirmed diagnosis of NP-C who have been tracked on an electronic database at the Department of Genetic Medicine, University of Manchester, UK. Patients were stratified according to accepted age-at-neurological-onset categories. Data on patients' clinical signs and symptoms, medical history and genetic studies are summarised using descriptive methods.

RESULTS

A total of 146 patients with NP-C were included, representing the full known UK NP-C cohort, as observed from database information between 1999 and the end of 2011: 72 patients (49 %) were alive at the end of the observation period. Among a total of 116 patients (79 %) who possessed at least one identified, disease-causing NP-C gene mutation, 114 (98 %) had NPC1 and two (2 %) had NPC2 mutations. Overall, 53/194 (27 %) identified mutations were novel. Six patients (4 %) had an early, non-neurological neonatal onset form of NP-C. The numbers (%) of patients with accepted age-at-neurological onset forms were: 8 (5 %) early-infantile onset, 51 (35 %) late-infantile onset, 42 (29 %) juvenile onset, and 25 (17 %) adolescent/adult onset. Fourteen patients diagnosed based on visceral symptoms and/or sibling history, confirmed in most cases by genetic analysis, did not have any neurological manifestations at last follow up (11 patients with mean [SD] age at last follow up 2.5 [1.8] years: 3 with mean [SD] age at death 20.8 [15.9] years). A total of 51 patients (35 %) received miglustat therapy. The mean (SD) overall treatment duration up to the end of the observation period was 2.6 (2.3) years.

CONCLUSIONS

This UK cohort is the largest national NP-C cohort reported to date, and confirms the wide phenotypic variability of the disease, as reported in other countries. Further analyses are required to assess the impact of miglustat therapy on neurological disease progression.

Health economic evaluation of plasma oxysterol screening in the diagnosis of Niemann-Pick Type C disease among intellectually disabled using discrete event simulation

BACKGROUND

Recently a less invasive method of screening and diagnosing Niemann-Pick C (NP-C) disease has emerged. This approach involves the use of a metabolic screening test (oxysterol assay) instead of the current practice of clinical assessment of patients suspected of NP-C (review of medical history, family history and clinical examination for the signs and symptoms). Our objective is to compare costs and outcomes of plasma oxysterol screening versus current practice in diagnosis of NP-C disease among intellectually disabled (ID) patients using decision-analytic methods.

METHODS

A discrete event simulation model was conducted to follow ID patients through the diagnosis and treatment of NP-C, forecast the costs and effectiveness for a cohort of ID patients and compare the outcomes and costs in two different arms of the model: plasma oxysterol screening and routine diagnosis procedure (anno 2013) over 5 years of follow up. Data from published sources and clinical trials were used in simulation model. Unit costs and quality-adjusted life-years (QALYs) were discounted at a 3% annual rate in the base case analysis. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

The outcomes of the base case model showed that using plasma oxysterol screening for diagnosis of NP-C disease among ID patients is a dominant strategy. It would result in lower total cost and would slightly improve patients' quality of life. The average amount of cost saving was $3642 CAD and the incremental QALYs per each individual ID patient in oxysterol screening arm versus current practice of diagnosis NP-C was 0.0022 QALYs. Results of sensitivity analysis demonstrated robustness of the outcomes over the wide range of changes in model inputs.

CONCLUSION

Whilst acknowledging the limitations of this study, we conclude that screening ID children and adolescents with oxysterol tests compared to current practice for the diagnosis of NP-C is a dominant strategy with clinical and economic benefits. The less costly, more sensitive and specific oxysterol test has potential to save costs to the healthcare system while improving patients' quality of life and may be considered as a routine tool in the NP-C diagnosis armamentarium for ID. Further research is needed to elucidate its effectiveness in patients presenting characteristics other than ID in childhood and adolescence.

Socio-economic burden of rare diseases: A systematic review of cost of illness evidence

Cost-of-illness studies, the systematic quantification of the economic burden of diseases on the individual and on society, help illustrate direct budgetary consequences of diseases in the health system and indirect costs associated with patient or carer productivity losses. In the context of the BURQOL-RD project ("Social Economic Burden and Health-Related Quality of Life in patients with Rare Diseases in Europe") we studied the evidence on direct and indirect costs for 10 rare diseases (Cystic Fibrosis [CF], Duchenne Muscular Dystrophy [DMD], Fragile X Syndrome [FXS], Haemophilia, Juvenile Idiopathic Arthritis [JIA], Mucopolysaccharidosis [MPS], Scleroderma [SCL], Prader-Willi Syndrome [PWS], Histiocytosis [HIS] and Epidermolysis Bullosa [EB]). A systematic literature review of cost of illness studies was conducted using a keyword strategy in combination with the names of the 10 selected rare diseases. Available disease prevalence in Europe was found to range between 1 and 2 per 100,000 population (PWS, a sub-type of Histiocytosis, and EB) up to 42 per 100,000 population (Scleroderma). Overall, cost evidence on rare diseases appears to be very scarce (a total of 77 studies were identified across all diseases), with CF (n=29) and Haemophilia (n=22) being relatively well studied, compared to the other conditions, where very limited cost of illness information was available. In terms of data availability, total lifetime cost figures were found only across four diseases, and total annual costs (including indirect costs) across five diseases. Overall, data availability was found to correlate with the existence of a pharmaceutical treatment and indirect costs tended to account for a significant proportion of total costs. Although methodological variations prevent any detailed comparison between conditions and based on the evidence available, most of the rare diseases examined are associated with significant economic burden, both direct and indirect.

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.