Biochemical study of sialidosis type I in a Russian family.
A 7-year-old boy from a Russian family with decreased vision and a cherry-red spot but without any somatic and mental abnormalities is described in this paper. The decreased neuraminidase activity in the child's leukocytes and cultured skin fibroblasts and his 10-fold increase in urinary sialyloligosaccharides allowed us to conclude that he was affected by type I sialidosis. Some other results of the biochemical study of this child and his parents are presented. It is the first case of sialidosis in the Russian population.