TABLE 41.1

Defects in glycoprotein degradation

Effects on degradation of
DisorderDefectGlycoproteinGlycolipidClinical symptoms
α-Mannosidosis (types I and II)α-mannosidasemajornonetype I: infantile onset, progressive mental retardation, hepatomegaly, death between 3 and 12 years
type II: juvenile/adult onset, milder, slowly progressive
β-Mannosidosisβ-mannosidasemajornonesevere quadriplegia, death by 15 months in most severe cases; mild cases have mental retardation, angiokeratoma, facial dysmorphism
Aspartylglucosaminuriaaspartyl-glucosaminidasemajornoneprogressive, coarse facies, mental retardation
Sialidosis (mucolipidosis I)sialidasemajorminorprogressive, severe mucopolysaccharidosis-like features, mental retardation
Schindler (types I and II)α-N-acetyl-galactosaminidaseyes?type I: infantile onset, neuroaxonal dystrophy. severe psychomotor and mental retardation, cortical blindness, neurodegeneration
type II: mild intellectual impairment, angiokeratoma, corpus diffusum
Galactosialidosisprotective protein/cathepsin Amajorminorcoarse facies, skeletal dysplasia, early death
Fucosidosisα-fucosidasemajorminorspectrum of severities includes psychomotor retardation, coarse facies, growth retardation
GM1 gangliosidosisβ-galactosidaseminormajorprogressive neurological disease and skeletal dysplasia in severe infantile form
GM2 gangliosidosisβ-hexosaminidaseminormajorsevere form: neurodegeneration with death by 4 years less severe form: slower onset of symptoms and variable symptoms, all relating to various parts of the central nervous system

From: Chapter 41, Genetic Disorders of Glycan Degradation

Cover of Essentials of Glycobiology
Essentials of Glycobiology. 2nd edition.
Varki A, Cummings RD, Esko JD, et al., editors.
Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 2009.
Copyright © 2009, The Consortium of Glycobiology Editors, La Jolla, California.

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