Nephrosialidosis

Maroteaux et al. (1978) proposed this term for a type of oligosaccharidosis in which a glomerular nephropathy develops early and causes death at a young age. The clinical and radiologic features are dysmorphic facies, visceral storage disease, early and severe mental retardation, and skeletal abnormalities of a type often seen in this group of diseases. Foam cells are found in the bone marrow and, late in the illness, a cherry red spot is present on funduscopy. The condition is inherited as an autosomal recessive. The leukocytes are deficient in alpha-(2-6) neuraminidase, a defect found also in the sialidoses (256550) and in galactosialidosis (256540), which have clinical differences. Aylsworth et al. (1979) observed a case of nephrosialidosis. Congenital ascites, early-onset pericardial effusion, nephrosis, and greater overall severity of clinical features distinguished the disorder from other forms of neuraminidase deficiency. Roth et al. (1988) gave follow-up on a patient reported by Kelly and Graetz (1977) to have isolated acid neuraminidase deficiency with the phenotype of type 2 infantile sialidosis. An unusual feature was the abrupt onset and fulminant course of the nephrotic syndrome from which she died at the age of 9 years and 8 months. The kidneys showed epithelial cell damage most marked in the glomeruli and proximal tubules, with stored material in the form of polar sialyloligosaccharides of high molecular weight. Nephrosis was reported by Sperl et al. (1990) in a brother and sister with infantile sialic acid storage disease (269920). Nephrosis has also been described in the Hurler syndrome (607014) (Taylor et al., 1986) but this must be a rare complication of that particular lysosomal storage disease.

It is by no means clear that nephrosialidosis is due to a mutation at a different locus from that represented by entry 256550.