Lysomal Storage Disorder

The Tarantula

Sialidosis & Galactosialidosis

Due to clinical features, these two clinical pictures are hardly distinguishable. Sialidosis is caused by a lysosomal neuramidase deficiency. Galactosialidosis is characterized by a deficiency of lysosomal neuraminidase and b-galactosidase. This is caused by a lack of an activator and transport protein for these two enzymes. Initially, this enzyme was called protective protein. Later, the protective protein was also characterized as Cathepsin A. Initially the children with sialidosis type II or galactosialidosis resemble children with MPS 1 (Hurler phenotype). The course especially in late infantile and juvenile forms can be complicated by renal failure with proteinuria. Probably the Hydrops fetalis is the most frequent and most severe manifestation of the disease.  Sialidosis type I - also called Cherry Red Spot Myoclonus Syndrome - is associated without the changes observed in MPS. In late childhood or adolescence, there is loss of visual acuity, polymyoclonus and seizures.

Sialidosis & Galactosialidosis | SphinCS - Clinical Science for LSD


Synonym: Mucolipidosis Type I
Etiology: Deficiency of alpha-N-acetyl-neuraminidase
Gene: Neu1 Gene
Mode of inheritance: Autosomal recessive

  • Sialidosis Type I
  • Sialidosis Type II 

Leading symptoms:
Sialidosis Type I
(Age of onset: childhood, adulthood)

  • Progressive Ataxia
  • Myoklonus
  • Epilepsy
  • Skeletal abnormalities
  • Psychomotor retardation/regression
  • Cherry red spot

Sialidosis Type II
(Age of onset: infancy, early childhood)

  • Congenital hydrops
  • Hepatosplenomegaly
  • Facial dysmorphia
  • Skeletal abnormalities
  • Psychomotor retardation
  • Cherry red spot


  • Measurement of the activity of alpha-N-acetyl-neuraminidase in fibroblasts
  • Molecular genetic analysis of Neu1 Gene

Only symptomatic


Synonym: Goldberg Syndrome
Etiology: Deficiency of alpha-N-acetyl -neuraminidase and ß-Galactosidase
Gene: Protective protein/cathepsin A(PPCA) Gene
Mode of inheritance: Autosomal recessive

  • Congenital/ early-infantile form
  • Late-infantile form
  • Juvenile/adult form

Leading symptoms
Congenital/ early-infantile form
(Age of onset: ≤ 3 months)

  • Hydrops fetalis
  • Hepatosplenomegaly
  • Facial dysmorphia
  • Dysostosis multiplex
  • Cherry red spot
  • Early blindness
  • Renal insufficiency
  • Cardiomegaly
  • Variable neurological symptoms

Late-infantile form
(Age of onset: > 3 months- 2 years)

  • Hepatosplenomegy
  • Facial dysmorphia
  • Dysostosis multiplex
  • Heart valve thickening
  • Hearing impairment
  • Cherry red spot, corneal clouding

Juvenile/adult form
(Age of onset: childhood, adolescence)

  • Facial dysmorphia
  • Myoklonus
  • Ataxia
  • Epilepsy
  • Cognitive decline
  • Spinal column abnormalities
  • Angiokeratoma

Current Studies

The "U.S. National Library of Medicine" provides a complete list of all international studies at The comparable EU website is less comprehensive:

Self-help groups

At the moment we are not aware of any self-help groups.


At present we have no literature available.