Classification of Lysomal Storage Disorders 

NeuroLearn NeuroHelp Metabolic @

Functions of lysosomes: The lysosome is the organalle that hydrolyses a large number of complex molecules. Most but not all lysosomal diseases are due to a genetic defect of one of the lysomal enzymes involved in the degradation of a specific substance. Such defect will lead to abnormal accumulation of the non-degraded substance. All known lysosomal diseases are inherited as recessive traits, mostly autosomal recessive. Lysosomal diseases affecting the CNS can basically divided into spingolipidoses and mucosaccharidoses.  

Classification of lysomal storage diseases:  

Sphingolipidoses Head

Gangliosidoses

GM2 gangliosidosis (autosomal recessive)

• Infantile form (Tay-Sachs disease)

• Type B: Hexosaminidase A deficiency

• Type O (Sandhoff): Hexosaminidase A and B deficiency

• Type AB: Activator protein deficiency

• Infantile, late infantile, juvenile and adult form

• Type B: Hexosaminidase A deficiency (different mutation from that of the infantile Type B form)

• Type B1: Low hexosaminidase A activity

GM1 gangliosidosis

• Type I (pseudo-Hurler disease, Landing disease): infantile onset

• Type II: late-infantile/juvenile onset

• Type III: adult onset

GM3 gangliosidosis

Gaucher disease

• Type I (adult onset, most common)

• Type II (acute infantile Gaucher disease or neuronopathic type)

• Type III (juvenile Gaucher disease)

Niemann-Pick disease

Group I: Sphingomyelinase deficiency

• Type A: Neurovisceral (infantile, juvenile and adult)

• Type B: Visceral only (infantile, juvenile and adult)

Group II: Not sphingomyelinase deficient

• Type C: Neurovisceral

• Type D: Possible pure visceral form (?)

Fabry’s disease

Ceramidosis (Lipogranulomatosis, Farber disease)

Sulfatidoses (metachromatic leukodystrophy)

Mucosulfatidosis (multiple sulfatase deficiency, Austin disease)

Globoid cell leukodystrophy (Krabbe disease)

Mucopolysaccharidoses (MPS) Head

• Hurler (MPS IH)

• Scheie disease (MPS IS or V)

• Hunter (MPS II)

• Sanfilippo (MPS III)

• Morquio (MPS IV)

• Maroteaux-Lamy (MPS VI)

• Sly (MPS VII)

Glycogenoses Head

• Glycogenosis type II and Pompe's disease

NeuroLearn NeuroHelp Metabolic  For Comment: KarMing-Fung@ouhsc.edu