Clinical spectrum of infantile free sialic acid storage disease

Infantile free sialic acid storage disease (ISSD) is a rare autosomal reces sive metabolic disorder caused by a lysosomal membrane transport defect, re sulting in accumulation of free sialic acid within lysosomes, Only a few ca ses have been described. We report on three new cases of ISSD with differen t modes of presentation: an infant with nephrotic syndrome, a case of fetal and neonatal ascites with heart failure, and a case of fetal ascites with esophageal atresia type III. From these patients and a review of the litera ture (27 cases total) we draw the following conclusions. 1) "Coarse facies, " fair complexion, hepatosplenomegaly, and severe psychomotor retardation a re constant findings in this disorder. 2) Nephrotic syndrome occurred in mo st cases (four in seven) in which renal evaluation was performed. Therefore , ISSD is an important cause of nephrosis in infants with a storage disorde r phenotype, 3) Fetal/neonatal ascites or hydrops was the mode of presentat ion in 13 (60%) of 21 cases, Thus, ISSD enters in the differential diagnosi s of hydrops fetalis with a storage disease phenotype, 4) Cardiomegaly was evident in nine cases. 5) Corneae were always clear, and albinoid fundi wer e reported in five cases, 6) Dysostosis multiplex was not prominent, 7) Bon e marrow aspiration could be negative, 8) Death ensued in early infancy wit h a mean age of 13.1 months. All reported deaths were caused by respiratory infections. (C) 1999 Wiley-Liss, Inc.