NEONATAL ASCITES DUE TO INFANTILE SIALIC- ACID STORAGE DISEASE

Metabolic diseases occur in approximately 10% of neonates with non-imm unologic hydrops fetalis, We report on a preterm infant (29 wk GA, bir th weight 2200 g) with infantile sialic acid storage disease (ISSD) as the underlying cause of his neonatal ascites. Clinical features inclu ded a coarse facies, pale skin with fair wispy hair, hepatosplenomegal y and cardiomyopathy. The finding of vacuolated lymphocytes in both pe ripheral blood and ascites suggested a lysosomal storage disease. ISSD was confirmed following the demonstration of raised free sialic acid concentrations in both urine and cultured fibroblasts. The patient die d at 6 months of age due to progressive respiratory insufficiency. In ISSD, free sialic acid is accumulated intralysosomally, probably due t o an impaired transport of sialic acid across the lysosomal membranes. The prognosis is extremely poor, Diagnosis can only be made by direct analysis of free sialic acid in urine, ascites, or cultured fibroblas ts. ISSD is very rare; only 15 cases have yet been reported. However, because of the difficulties involved in diagnosing ISSD, its role in t he differential diagnosis of neonatal ascites may be underestimated.