Background: Gangliosidoses belong to the group of genetic lipid metabolism disorders, caused by defects of lisosome enzymes, inherited by an autosomal recessive trait. Gangliosidosis GM1 is caused by the
deficiency of the acid beta-galactosidase(GLB11) resulting in the storage of the substrate – GM1
ganglioside in brain and visceral organs. GM 1 gangliosidosis comprises of three phenotypes,
depending on the age of onset: an infantile, juvenile and an adult type. In the infantile type dismorphic features severe psychomotor retardation, hepatosplenomegaly, bone changes and a cherry-red spot in the macular region are seen. The juvenile GM1 gangliosidosis has no such external distinguishing features. In the adult type behavioral problems, dementia, extrapiramidal movements are especially prominent. The authors present symptoms, clinical course and laboratory findings at three children with
diagnosed GM1 gangliosidosis.
Case Report: The authors present three patients with the GM1 gangliosidosis – a 10-month-old boy with
the infantile type, a 5-month-old girl, with the enzyme activity at the level characteristic for the
juvenile type and a 16-year-old boy with the adult type.
Conclusions: Although the GM1 gangliosidosis is not exceedingly rare disorder and has been already relatively precisely described, the diagnosis can be sometimes very difficult. In spite of that the cases 1
and 3 represent typical clinical features of the disease, the diagnosis was established relatively
late. The case 2 is unusual because of its early beginning and the enzyme activity at the level
characteristic for the juvenile type. That is why we believe that such case reports are important
for improving our knowledge and understanding of the disease.

Keywords: GM1 gangliosidosis, Lysosomal enzymes, storage diseases