Niemann-Pick Disease, Type C1

Alternative Names

  • NPC1
  • Niemann-Pick Disease, Type C
  • NPC
  • Niemann-Pick Disease with Cholesterol Esterification Block
  • Niemann-Pick Disease, Subacute Juvenile Form
  • Niemann-Pick Disease, Chronic Neuronopathic Form
  • Niemann-Pick Disease without Sphingomyelinase Deficiency
  • Neurovisceral Storage Disease with Vertical Supranuclear Ophthalmoplegia
  • Niemann-Pick Disease, Type D
  • Niemann-Pick Disease, Nova Scotian Type
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WHO-ICD-10 version:2010

Endocrine, nutritional and metabolic diseases

Metabolic disorders

OMIM Number

257220

Mode of Inheritance

Autosomal recessive

Gene Map Locus

18q11-q12

Description

Niemann-Pick disease type C (NPC) is a complex lysosomal lipidosis (lipid storage disease) that results in hepatosplenomegaly and progressive neurological involvement. NPC is the chronic neuronopathic form of Niemann-Pick diseases. NPC can be subdivided into two types: NPC1 which has the frequency of 95% and NPC2. In both types, intracellular transport of LDL-derived exogenous cholesterol is impaired and that will result in accumulation of non-esterified cholesterol in lysosomes causing delayed homeostatic reactions of cholesterol. Cultured fibroblasts showed a partial deficiency of sphingomyelinase activity. Sphingomyelinase is the enzyme that targets a distinctive lipid (sphingomyelin) in the cells. NPC can affect infants, children, or adults. Infants may have ascites and severe liver and respiratory diseases due to infiltration of the liver and the lungs. In 50% of the cases, the neonatal period is marked by prolonged cholestatic jaundice that may regress spontaneously, but sometimes it may progresses to rapidly fatal liver failure. Infants without liver or respiratory diseases will have hypotonia and developmental delay. Classically, the disease occurs in the middle to late childhood and characterized by the insidious onset of ataxia, vertical supranuclear gaze palsy (VSGP), and dementia. Dementia and psychiatric symptoms are more likely to present in affected adults. Dystonia and seizures are also common in NPC. Death usually occurs in the second or third decade due to aspiration pneumonia. Males and females are equally affected.

Molecular Genetics

Niemann-Pick disease type C (NPC) is inherited as an autosomal recessive trait. Mutations in two genes are recognized to be the cause of NPC. These genes are NPC1 and NPC2. Alterations in NPC1 are responsible for the majority of NPC cases. To date, more than 100 mutations have been detected in NPC1 gene with the predominance of missense mutations; however, there are no apparent hot spots. The product of NPC-1 gene is a membrane-bound protein that is involved in vesicular trafficking of sterols. This sterol trafficking protein is responsible for exchanging the cholesterol amongst the various subcellular compartments.

Most patients with NPC1 mutations have compound heterozygosity with unique mutations according to their race. A common I1061T mutation is found in the United Kingdom, in France, and in the Hispanic population. The G992W mutation is found in the Acadian population of Nova Scotia.

Epidemiology in the Arab World

View Map
Subject IDCountrySexFamily HistoryParental ConsanguinityHPO TermsVariantZygosityMode of InheritanceReferenceRemarks
257220.G.1PalestineNM_000271.5:c.2974G>THomozygousAutosomal, RecessiveAl-Jasmi et al. 2013 2 Palestinian patien...

Other Reports

Egypt

Bukhari (2005) reported an 8-month-old Egyptian girl with Niemann-Pick disease.  She was hospitalized due to an idiopathic nodular panniculitis infection in Saudi Arabia.  She developed high fever reaching 41C, and erythematous yellowish popular skin lesions in her whole body, sparing the face.  She was treated with topical fusidic acid with betamethasone valerate cream; her skin resolved completely after four weeks.

Iraq

Fensom et al. (1990) (Emirates Med J. 1990; 8:215-9) reported two Iraqi cousins living in the UAE with Niemann-Pick disease Type C (NPC). The first patient was one of female twins. Her parents were first cousins once removed and her twin sister was clinically normal. At five months of age, she had delayed motor development and speech. Hepatosplenomegaly was observed at seven months of age. Liver function tests were within the normal range in the 13 months and the bone marrow showed foamy histiocytes with staining properties not to support NPC. However, the diagnosis of NPC was established by cultured fibroblasts studies. Psychomotor regression was evident by three years leading to death in the sixth year. Cultured fibroblast of the normal twin showed a reduced rate of intracellular esterification of exogenously derived cholesterol. Thus, Fensom et al. (1990) concluded, for the first time, that heterozygous carriers of NPC might be identified by demonstrating a partial defect in their cholesterol metabolism which would be important for consanguineous marriages. Also, it was found that sphingomyelinase assay would not detect heterozygotes. The second patient was a boy and his parents were first cousins. He presented hepatosplenomegaly at two days of age followed by prolonged jaundice for most of the first year. Then, the jaundice disappeared and subsequently he was noticed to have mental handicap. His alkaline phosphate activity was elevated. The diagnosis of NPC was established by cultured skin fibroblast assay.

Jordan

Fensom et al. (1990) (Emirates Med J. 1990; 8:215-9)  described a Jordanian girl living in the UAE who was diagnosed to have NPC. Her parents were first cousins. She developed severe prolonged jaundice that was considered to be due to biliary atresia and it extended for 11 months. Her three previous brothers had similar jaundice and all brothers died with identical illness between four and 16 weeks of age. Also, she was noted to have hepatosplenomegaly since she was born. Serum activities of transaminases and alkaline phosphatase were elevated. At 11 months, she had delay motor development. When she was three years old, she had ataxic gait, weakness, hypotonia of the lower limbs, and a small hernia of the linea alba. A bone marrow aspirate revealed abnormal vacuolated macrophages. Liver biopsy showed fibrosis, moderate giant cell transformation, and large deposits of abnormal storage material in Kupffer cells and hepatocytes. Skin fibroblast studies were the reliable diagnostic method of NPC.

Saudi Arabia

[See: Egypt > Bukhari, 2005].

Moammar et al. (2010) reviewed all patients diagnosed with inborn errors of metabolism (IEM) from1983 to 2008 at Saudi Aramco medical facilities in the Eastern province of Saudi Arabia. During the study period, 165530 Saudi infants were born, of whom a total of 248 newborns were diagnosed with 55 IEM. Affected patients were evaluated based on clinical manifestations or family history of similar illness and/or unexplained neonatal deaths. Almost all patients were born to consanguineous parents. Lysosomal storage disorders were the most diagnosed category of IEM in this cohort (74 out of 248 cases, 30%). Among them, 2 cases from 2 families were found to have Neimann-Pick type C, with an estimated incidence of 1 per 100,000 live births. All cases of Neimann-pick were diagnosed by conventional filipin staining and the lack of cholesterol esterification in skin fibroblasts of the patients. The authors concluded that data obtained from this study underestimate the true figures of various IEM in the region. Therefore, there is an urgent need for centralized newborn screening program that utilizes tandem mass spectrometry, and offers genetic counseling for these families.

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