Oligosaccharide and Ganglioside Neuraminidase Activities of Mucolipidosis I (Sialidosis) and Mucolipidosis II (I-Cell Disease) Fibroblasts

Fibroblasts cultured from the skin of patients with the genetic diseases mucolipidosis I and mucolipidosis II were found deficient in a neuraminidase specific for both an α23 and and α2 6 type of neuraminosyl linkage of sialyl oligosaccharides. Obligate heterozygotes (parents) showed an intermediate activity in mucolipidosis I, but a normal one in mucolipidosis II. The neuraminidase activity of mucolipidosis I fibroblasts towards gangliosides, measured at pH 4.5 in the presence of Triton X-100, was within the range of normal controls with gangliosides Gm3 and GD3, but somewhat diminished with a bovine brain ganglioside preparation. In mucolipidosis II, neuraminidase activity was markedly de…