Six juvenile and adult patients with progressive neurological diseases and beta-galactosidase deficiency were reported. Any diseases known to date were denied. These cases together with ten case reports in the literature were reviewed and were classified into three groups from clinical and biochemical points. Group 1 patients were characterized by progressive ataxia and myoclonus with gargoyl changes and macular cherry-red spots. In this syndrome beta-galactosidase activity seems to be secondarily affected by other biochemical defects. A group 2 patient showed similar neurological manifestations without gargoyle changes or macular cherry-red spots. Patients with these clinical features not associated with beta-galactosidase deficiency have also been described in the literature. Group 3 patients had progressive pyramidal and extrapyramidal disease without gargoyl changes or macular cherry-red spots. These cases may represent juvenile and adult type GM1-gangliosidosis. Accumulation of GM1 has not yet been demonstrated.