These infants are often born with coarse facial features, such as a flat nasal bridge, puffy eyelids, enlargement of the gums, and excessive tongue size (macroglossia).

[citation needed] The role of sialidase is to remove a particular form of sialic acid (a sugar molecule) from sugar-protein complexes (referred to as glycoproteins), which allows the cell to function properly.

Because the enzyme is deficient, small chains containing the sugar-like material accumulate in neurons, bone marrow, and various cells that defend the body against infection.

[citation needed] The detection of high urinary sialyl oligosaccharides and the confirmation of lysosomal enzyme deficiency in leukocytes or cultured fibroblasts make the diagnosis.

[2] Treatment of sialidosis is similar to the other progressive myoclonic epilepsy disorders, which consists of managing seizures and myoclonus along with palliative, supportive, and rehabilitative care.