Sialic acidstorage disease

babygirlwithcoarsefacial features, hepatosplenomegaly, and developmental delay hadraised freesialic acidconcentra- tions inherurine andcultured fibroblasts. Shediedaged13months. Sialic acidisan important constituent ofmanyglycoproteins andglycolipids; impaired release fromthe lysosome maybetheunderlying biochemical defect. Disorders ofsialic acid metabolism fall into four categories. Raisedconcentrations ofbound sialic acidarefoundinconditions associated withneuraminidase deficiency. 'No enzyme deficiency hasbeenshowninthree other cate- gories where raised concentrations offree sialic acidarefound: Salla disease, sialuria, and severe infantile sialic acid storage disease. Salla disease, namedafter anareainnorthern Fin- land, comprises progessive psychomotor retar- dation withlysosomal storage inpatients reaching adult life.2 Twocases ofsialuria have beendescribed whereonlysialic acidinthe urine wasraised. Thesepatients hadcoarse facies, hepatosplenomegaly, a mildclinical course, andnolysosomal storage.3 Thiscase report concerns thefourth category: severe infantile sialic acidstorage disease. t,~~~~~~~~~~~~~~~~~~~~~~~~~~.. eyebrows andtelang~~~~~~~~.iectasias weeks She was readmittd. at 11 1 and 16 's'-D,...~~~~~~~~~~~~~~~~~~~~~~~~..