Heterogeneity of carboxypeptidase activity in infantile-onset galactosialidosis.

The clinical presentation and laboratory findings in seven patients with neonatal/infantile-onset galactosialidosis are presented. We detected no carboxypeptidase activity in two of these patients, while an enzyme with different apparent Km, or both Km and Vm, were found in five others. We could not establish a correlation between the biochemical characteristics of carboxypeptidase and the age of onset, progression, or other clinical features of galactosialidosis.