Lysosomal Storage Disorders

Introduction

During general construction work, the engineers use a lot of materials to accomplish their tasks. After the work, damaged materials are packed to be trash or recycled. Have you asked yourself what happens after metabolism? Our body cells digest damaged macromolecules and recycled them, they also digest pathogens invading our body, and all of these are done by the lysosomes. This article focuses on the major classes we can find all the lysosomal storage disorders.

Here's everything you will learn in the article:

• What are lysosomes?
• Functions of lysosomes
• What are lysosomal storage disorders?
• Causes of lysosomal storage disorders
• 9 classes of lysosomal storage disorders

What are Lysosomes?

Lysosomes are cell organelles found in cells that contain packet hydrolytic enzymes. These organelles are found in all animal cells, except Erythrocytes.

Functions of Lysosomes

The lysosomes have three unique functions:

1. Degradation/digestion of macromolecules (proteins, carbohydrates, lipids, nucleotides).

2. Response to pathogens or foreign substances (bacteria, viruses, and other antigens).

3. Cell membranes repair.

What are lysosomal storage disorders?

Lysosomal storage diseases (LSDs) are genetic errors of metabolism distinguished by the accumulation of substrates in excess in various organs' cells due to the defective functioning of lysosomes.

 

Causes of Lysosomal storage disorders

The lysosomal storage disorders are caused by mutations in a gene of a cell that will code for defective enzymes or proteins. 

These disorders are autosomal recessive, which means the offspring inherited the defective enzyme gene from each parent.

9 Classes Of Lysosomal Storage Disorders.

There are about 40 to 50 lysosomal storage disorders and they are classified based on their causes. we will look at 9 classes of lysosomal storage disorders in this article.

1. Sphingolipidoses = are a group of human lysosomal lipid storage disorders or degenerative storage disorders caused by deficiency of a catabolism enzyme.

Examples of Sphingoilipidoses are Gaucher disease(GBA), Fabry disease, etc...

2. Lipid storage diseases = also known as lipidoses, are groups of metabolic disorders that result in the accumulation of harmful lipids materials in human tissues and cells.

Acid lipase deficiency: Wolman disease and cholesterol ester storage disease(LIPA) are examples of LSD.

3. Mucopolysaccharidoses (MPS) = are a group of lysosomal storage disorders that occur when the body lacks the enzymes needed to break down and store complex sugar molecules called glycosaminoglycans.

MPS I or Hurler Syndrome (IDUA).

4. Post-translational modification defects = are a defect that occurs due to PTM processing. Post-translational modification defects can result in various human diseases like cancer, heart disease, Huntington's disease, etc.

Mucolipidosis II a/b, and I-cell disease (GNPTAB).

5. Glycoproteinoses = are diseases affecting glycoprotein as a result of a lysosomal storage disorder. Alpha-Mannosidosis (MAN2B1). 

6. Integral membrane protein disorders = are group diseases that can occur due to mutations in membrane protein assembling.

An example is Niemann-pick disease types C1 and C2 (NPC1 and NPC2).

7. LRO disorders = Lysosomes Related Disorders are genetic abnormalities of organelles that share features with the lysosomes but are different in morphology, composition, and function. An example of LRO disorders is Hermansky-pudlak disease type-1 (HPS1).

8. Glycogen storage disease (GSD) = is a rare inherited metabolic disorder as a result of an enzyme deficiency affecting the glycogen synthesis and glycogen breakdown. An example of GSD is Pompe disease (GGA).

9. Neuronal Ceroid Lipofuscinoses = are lysosomal storage disorders of nerves cell that cause them to degenerate and accumulate autofluorescent ceroid lipopigments in most cells. An example is ceroid lipofuscinosis neuronal,

CLN1 (PPT1). 

Several lysosomal storage disorders have been affecting the world population ranging from infants to adults most especially infants.

Understanding LSDs properly for diagnosis means you should have a clear knowledge about the group each of them is placed in.  The classes give a clear view of their origin and how to better treat each LSDs.

l hope this was helpful.