We report a unique case of an infant with a severe dilated cardiomyopathy as the clinical presentation of sialidosis type II (OMIM 256550), a rare autosomal recessive inherited lysosomal storage disease that is characterized by partial or complete deficiency of α-neuraminidase, following mutations in the gene neuraminidase 1 (<i>NEU1</i>), located on the short arm of chromosome 6 (6p21.3). Here, NEU1 is linked to sialidosis type II.