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GM1 Gangliosidosis

  • Author: David H Tegay, DO, FACMG; Chief Editor: Luis O Rohena, MD  more...
Updated: Dec 11, 2014


GM1 gangliosidosis is an autosomal recessive lysosomal storage disorder characterized by the generalized accumulation of GM1 ganglioside, oligosaccharides, and the mucopolysaccharide keratan sulfate (and their derivatives). Deficiency of the lysosomal hydrolase, acid β -galactosidase, causes GM1 gangliosidosis and Morquio disease type B (ie, mucopolysaccharidosis type IVB).[1] Three clinical subtypes of GM1 gangliosidosis are recognized, classified by age of onset, as follows:

  • Infantile (type 1): The classic infantile subtype combines the features of a neurolipidosis (ie, neurodegeneration, macular cherry-red spots) with those of a mucopolysaccharidosis (ie, visceromegaly, dysostosis multiplex, coarsened facial features). This form of G M1 gangliosidosis most frequently presents in early infancy and may be evident at birth. [2]
  • Juvenile (type 2): The juvenile subtype is marked by a slightly later age of onset and clinical variability in the classic physical features.
  • Adult (type 3): The adult subtype is marked by normal early neurologic development with no physical stigmata and subsequent development of a slowly progressive dementia with parkinsonian features, extrapyramidal disease, and dystonia. [3, 4, 5]


Acid β -galactosidase is a lysosomal hydrolase that catalyzes the removal of the terminal β -linked galactose from glycoconjugates (eg, GM1 ganglioside), generating GM2 ganglioside. It also functions to degrade other β -galactose–containing glycoconjugates, such as keratan sulfate.

Enzyme activity is markedly reduced in patients with GM1 gangliosidosis. Deficiency of acid β -galactosidase results in the accumulation of glycoconjugates in body tissues and their excretion in urine. GM1 ganglioside and its derivative asialo-GM1 ganglioside (GA1), glycoprotein-derived oligosaccharides, and keratan sulfate are found at elevated intracellular concentrations.[1, 6, 7, 8, 9]

Gangliosides are normal components of cell membranes, particularly neurons, and GM1 is the major ganglioside in the vertebrate brain. Accumulation of toxic asialo-compound and lyso-compound GM1 ganglioside derivatives is believed to be neuropathic.[1]




United States

GM1 gangliosidosis is a rare disorder, and data concerning incidence are not widely available. The estimated incidence is 1:100,000-200,000 live births.[2]


An unusually high incidence of 1 case per 3700 live births has been reported in the population of Malta.[10]


The infantile form (type 1) typically presents between birth and age 6 months with progressive organomegaly, dysostosis multiplex, facial coarsening, and rapid neurologic deterioration within the first year of life. Death usually occurs during the second year of life because of infection (usually due to pneumonia that results from recurrent aspiration) and cardiopulmonary failure.

The juvenile form (type 2) typically presents at age 1-2 years with progressive psychomotor retardation. Little visceromegaly and milder skeletal disease are present compared to the infantile form. Death usually occurs before the second decade of life.

The adult form (type 3) typically presents during childhood or adolescence as a slowly progressive dementia with prominent parkinsonian features and extrapyramidal disease, particularly dystonia. Marked phenotypic variability may occur. Age at death may widely vary.


GM1 gangliosidosis is found in all races, although specific alleles can be identified in certain ethnic groups. A high frequency of GM1 gangliosidosis has been reported from Southern Brazil, and a large number of Japanese patients with the adult form have been reported.[11, 1]


All 3 types of GM1 gangliosidosis are inherited as autosomal recessive traits and have equal sex distributions.


The infantile form (type 1) typically presents from birth to age 6 months, the juvenile form (type 2) typically presents in children aged 1-3 years, and the adult form (type 3) typically presents during childhood or adolescence.

Contributor Information and Disclosures

David H Tegay, DO, FACMG Associate Professor and Chair, Department of Medicine, NYIT College of Osteopathic Medicine; Director, Genetics Division, Department of Pediatrics, Nassau University Medical Center

David H Tegay, DO, FACMG is a member of the following medical societies: American College of Medical Genetics and Genomics, American College of Osteopathic Internists, American Osteopathic Association, Federation of American Societies for Experimental Biology, American Society of Human Genetics

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

David Flannery, MD, FAAP, FACMG Vice Chair of Education, Chief, Section of Medical Genetics, Professor, Department of Pediatrics, Medical College of Georgia

David Flannery, MD, FAAP, FACMG is a member of the following medical societies: American Academy of Pediatrics, American College of Medical Genetics and Genomics

Disclosure: Nothing to disclose.

Chief Editor

Luis O Rohena, MD Chief, Medical Genetics, San Antonio Military Medical Center; Assistant Professor of Pediatrics, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Assistant Professor of Pediatrics, University of Texas Health Science Center at San Antonio

Luis O Rohena, MD is a member of the following medical societies: American Academy of Pediatrics, American Chemical Society, American College of Medical Genetics and Genomics, American Society of Human Genetics

Disclosure: Nothing to disclose.


The authors and editors of eMedicine gratefully acknowledge the contributions of previous author Shari Fallet, DO, to the original writing and development of this article.

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