Sialidosis presenting as severe nonimmune fetal hydrops is associated with two novel mutations in lysosomal α-neuraminidase

Sialidosis is a lysosomal storage disease characterized by accumulation of sialylated oligosaccharides in tissues, blood and urine and is caused by mutations in the gene for lysosomal α-neuraminidase (NEU1). There is wide variability in the age of onset and severity of symptoms in sialidosis. We report here a case of sialidosis due to novel mutations in NEU1 presenting as severe nonimmune hydrops fetalis.