World Library  
Flag as Inappropriate
Email this Article

Lysosomal storage disease

Article Id: WHEBN0000580526
Reproduction Date:

Title: Lysosomal storage disease  
Author: World Heritage Encyclopedia
Language: English
Subject: Sialidosis, List of ICD-9 codes 240–279: endocrine, nutritional and metabolic diseases, and immunity disorders, Glycoproteinosis, Pseudo-Hurler polydystrophy, Salla disease
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Lysosomal storage disease

Lysosomal storage disease
Micrograph of Gaucher disease, with cells that have the characteristic crumpled tissue paper-like cytoplasm. H&E stain.
Classification and external resources
ICD-10 E75-E77
MeSH D016464

Lysosomal storage diseases (LSDs; ) are a group of approximately 50 rare inherited metabolic disorders that result from defects in lysosomal function.[1] Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other parts of the cell for recycling. This process requires several critical enzymes. If one of these enzymes is defective, because of a mutation, the large molecules accumulate within the cell, eventually killing it.[2]

Lysosomal storage disorders are caused by lysosomal dysfunction usually as a consequence of deficiency of a single enzyme required for the metabolism of lipids, glycoproteins (sugar containing proteins) or so-called mucopolysaccharides. Individually, LSDs occur with incidences of less than 1:100,000; however, as a group the incidence is about 1:5,000 - 1:10,000. Most of these disorders are autosomal recessively inherited such as Niemann-Pick disease, type C, however a few are X-linked recessively inherited, such as Fabry disease and Hunter syndrome (MPS II).

The lysosome is commonly referred to as the cell’s recycling center because it processes unwanted material into substances that the cell can utilize. Lysosomes break down this unwanted matter via enzymes, highly specialized proteins essential for survival. Lysosomal disorders are usually triggered when a particular enzyme exists in too small an amount or is missing altogether. When this happens, substances accumulate in the cell. In other words, when the lysosome does not function normally, excess products destined for breakdown and recycling are stored in the cell.

Like other genetic diseases, individuals inherit lysosomal storage diseases from their parents. Although each disorder results from different gene mutations that translate into a deficiency in enzyme activity, they all share a common biochemical characteristic – all lysosomal disorders originate from an abnormal accumulation of substances inside the lysosome.

Lysosomal storage diseases affect mostly children and they often die at a young and unpredictable age, many within a few months or years of birth. Many other children die of this disease following years of suffering from various symptoms of their particular disorder.

Contents

  • Symptoms 1
  • Diagnosis 2
  • Treatment 3
  • History 4
  • Classification 5
    • Standard classification 5.1
    • By type of defect protein 5.2
    • Lysosomal Storage Disorders 5.3
  • See also 6
  • References 7
  • External links 8

Symptoms

The symptoms of lysosomal storage disease vary, depending on the particular disorder and other variables like the age of onset, and can be mild to severe. They can include developmental delay, movement disorders, seizures, dementia, deafness and/or blindness. Some people with lysosomal storage disease have enlarged livers (hepatomegaly) and enlarged spleens (splenomegaly), pulmonary and cardiac problems, and bones that grow abnormally.

Diagnosis

The majority of patients are initially screened by enzyme assay, which is the most efficient method to arrive at a definitive diagnosis. In some families where the disease-causing mutation(s) is known and in certain genetic isolates, mutation analysis may be performed. In addition, after a diagnosis is made by biochemical means, mutation analysis may be performed for certain disorders.

Treatment

There are no cures for lysosomal storage diseases and treatment is mostly symptomatic, although bone marrow transplantation and enzyme replacement therapy (ERT) have been tried with some success.[3][4] In addition, umbilical cord blood transplantation is being performed at specialized centers for a number of these diseases. In addition, substrate reduction therapy, a method used to decrease the accumulation of storage material, is currently being evaluated for some of these diseases. Furthermore, chaperone therapy, a technique used to stabilize the defective enzymes produced by patients, is being examined for certain of these disorders. The experimental technique of gene therapy may offer cures in the future.[5]

History

intracellular digestion and recycling of macromolecules. This was the scientific breakthrough that would lead to the understanding of the physiological basis of the Lysosomal Storage Diseases. Pompe disease was the first disease to be identified as an LSD in 1963, with L. Hers reporting the cause as a deficiency of α-glucosidase. Hers also suggested that other diseases, such as the Mucopolysaccharidosis, might be due to enzyme deficiencies.

Classification

Standard classification

The lysosomal storage diseases are generally classified by the nature of the primary stored material involved, and can be broadly broken into the following: (ICD-10 codes are provided where available)

Also, glycogen storage disease type II (Pompe disease) is also a defect in lysosomal metabolism,[6] although it is otherwise classified into E74.0 in ICD-10. Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of the amino acid cystine.

By type of defect protein

Alternatively to the protein targets, lysosomal storage diseases may be classified by the type of protein that is deficient and is causing buildup.

Type of defect protein Disease examples Deficient protein
Lysosomal enzymes primarily Tay-Sachs disease, I-cell disease,[7] Sphingolipidoses
(e.g., gangliosidosis: Gaucher, Niemann-Pick disease and Glycolipids: Metachromatic Leukodystrophy)
Various
Posttranslational modification of enzymes Multiple sulfatase deficiency Multiple sulfatases
Membrane transport proteins Mucolipidosis type II and IIIA N-acetylglucosamine-1-phosphate transferase
Enzyme protecting proteins Galactosialidosis Cathepsin A
Soluble nonenzymatic proteins GM2-AP deficiency, variant AB, Niemann-Pick disease, type C2 GM2-AP, NPC2
Transmembrane proteins SAP deficiency Sphingolipid activator proteins
Niemann-Pick disease, type C1 NPC1
Salla disease Sialin
Unless else specified in boxes, then ref is:[8]

Lysosomal Storage Disorders

Following are lysosomal storage diseases:

Sphingolipidoses

Mucopolysaccharidoses

Mucolipidosis

Lipidoses

Oligosaccharide

Lysosomal Transport Diseases

Glycogen Storage Diseases

Other



See also

References

  1. ^ Winchester B, Vellodi A, Young E (2000). "The molecular basis of lysosomal storage diseases and their treatment". Biochem. Soc. Trans. 28 (2): 150–4.  
  2. ^ Reece, Jane; Campbell, Neil (2002). Biology. San Francisco: Benjamin Cummings. pp. 121–122.  
  3. ^ Clarke JT, Iwanochko RM (2005). "Enzyme replacement therapy of Fabry disease". Mol. Neurobiol. 32 (1): 043–050.  
  4. ^ Bruni S, Loschi L, Incerti C, Gabrielli O, Coppa GV (2007). "Update on treatment of lysosomal storage diseases". Acta Myol 26 (1): 87–92.  
  5. ^ Ponder KP, Haskins ME (2007). "Gene therapy for mucopolysaccharidosis". Expert Opin Biol Ther 7 (9): 1333–1345.  
  6. ^ eMedicine Specialties > Neurology > Pediatric Neurology > Lysosomal Storage Disease Author: Noah S Scheinfeld, MD, JD, FAAD. Coauthor(s): Rowena Emilia Tabamo, MD; Brian Klein, MD. Updated: Sep 25, 2008
  7. ^ Medical Physiology (2nd Edition) – W. Boron & E. Boulpaep, Saunders Press
  8. ^ Table 7-6 in:Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology. Philadelphia: Saunders.   8th edition.

External links

  • Hide & Seek Foundation For Lysosomal Disease Research
  • Global Genes Project, Rare Disease Support Organization
  • MLD Foundation
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.