Degenerative disorders with visceral storage include GM1 gangliosidosis (lysosomal deficiency of beta galactosidase), Sandhoff disease (lysosomal deficiency of hexosaminidase A and B), Farber disease (lysosomal deficiency of ceramidase), sialidosis (lysosomal deficiency of alpha neuroaminidase without the presence of alpha neuroaminidase in the cytosol), infantile sialic acid storage disease (lysosomal deficiency of alpha neuroaminidase with excessive cytosol alpha neuroaminidase due to the production of alpha neuroaminidase without the marker that guides it to the lysosomes), Zellweger syndrome or cerebrohepatorenal syndrome (peroxisomal disease characterized by peroxisomal organelles without enzymes), and neonatal adrenoleukodystrophy (peroxisomal disease characterized by peroxisomal organelles with a decreased amount of enzymes).
The diagnosis of these disorders is established by enzymatic studies in fibroblasts or leukocytes, except for sialidosis, infantile sialic acid storage disease, Zellweger syndrome, and neonatal adrenoleukodystrophy. The diagnosis of sialidosis requires fibroblast studies for the deficient enzyme. Studies of leukocytes are not revealing. Neonates with sialidosis may have hydrops fetalis. In infantile sialic acid storage disease, no enzyme deficiency has been found. Infantile sialic acid storage disease is diagnosed by the presence of excessive sialic acid in plasma and urine in the presence of normal alpha-neuroaminidase activity in fibroblasts. Neonates with infantile sialic acid storage disease usually have thin white hair. Zellweger syndrome and neonatal adrenoleukodystrophy are diagnosed by liver biopsy or microscopic evaluation of cultured fibroblasts. Electron microscopy of liver tissue or fibroblasts reveals the presence of peroxisomes that are empty of enzymes in Zellweger syndrome and have very little enzymes in neonatal adrenoleukodystrophy.