Biochemical study of a 6 years old child with decreased visus and cherry red spot but without any somatic and mental abnormalities was carried out. Leukocyte lysosomal hydrolases exhibited a distinct deficiency of neuraminidase activity in the child and a decrease of the enzyme activity in the parents of the child. The neuraminidase activity in leukocytes of mother and father constituted 37% and 53% of the control values, respectively; these data enabled to consider the parents as heterozygotes. Excretion of total sialylolygosaccharides with urine was increased 4-5-fold in the patient as compared with suitable controls. It was concluded that the patient studied was affected by sialidosis of the type I.
Adult Child