NEURAMINIDASE DEFICIENCY PRESENTING AS A NEPHROSIALIDOSIS - THE FIRSTCASE DETECTED IN POLAND

A defect of lysosomal neuraminidase (sialidase N-acetyl-neuramine acid hydrolase EC 3.2.1.18) leads to a wide spectrum of phenotypes, the mo st severe of which is nephrosialidosis. A 4-year-old boy of related pa rents, born at term with hydrops fetalis, is reported. Hydrocephalus w as detected at 2 months of age. The child's course over 3 years was ch aracterized by slow growth and psychomotor development. He had mild he patosplenomegaly, joint restriction, gingival hypertrophy, lens opacit ies and cherry-red spot. Coarse facial features and depressed nasal br idge were discreet. At the age of 3.5 years, he developed gradual prog ressive edema, decreased activity and increased fatigue. A diagnosis o f nephrotic syndrome was made because of massive proteinuria. Thin-lay er chromatography of urinary oligosaccharides revealed the presence of several abnormal sialyloligosaccharides. The diagnosis was confirmed by measurement of neuraminidase activity in cultured skin fibroblasts.