Abstract
Two distinct metabolic derangements are encompassed under the eponym Niemann-Pick disease (NPD). The first is due to the deficient activity of the lysosomal enzyme acid sphingomyelinase (ASM). Patients with this enzyme deficiency are classified as having types A and B NPD. Type A NPD patients exhibit hepatosplenomegaly in infancy and profound central nervous system involvement. They rarely survive beyond 2 years of age. Type B patients also have hepatosplenomegaly and pathologic alterations of their lungs, but there are usually no central nervous system signs. The age of onset and rate of disease progression varies greatly among type B patients, and they frequently live into their fourth decade. Patients with phenotypes intermediate between types A and B NPD also have been identified. These individuals represent the expected continuum caused by inheriting different mutations in the ASM gene (SMPD1).Patients in the second NPD category are designated as having types C and D NPD. These individuals may have mild hepatosplenomegaly, but the central nervous system is profoundly affected. Impaired intracellular trafficking of cholesterol causes types C and D NPD, and two distinct gene defects have been found. All type D patients originate from a common Nova Scotian ancestry.
Original language | English |
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Title of host publication | Rosenberg's Molecular and Genetic Basis of Neurological and Psychiatric Disease |
Subtitle of host publication | Fifth Edition |
Publisher | Elsevier Inc. |
Pages | 313-320 |
Number of pages | 8 |
ISBN (Electronic) | 9780124105294 |
ISBN (Print) | 9780124105492 |
DOIs | |
State | Published - 13 Nov 2014 |
Keywords
- Acid Sphingomyelinase
- Enzyme replacement therapy
- Phenotypic spectrum
- Sphingomyelin