Galactosialidosis is a lysosomal storage disease associated with a deficiency the lysosomal protective protein cathepsin A (PPCA), which aggregates with beta-galactosidase and sialidase enzymes to protect them from degradation. Therefore a deficiency of PCCA results in a secondary deficiency of these enzymes. There are 3 distinct subtypes, early infantile, late infantile, and juvenile/adult.
Clinical features common to late infantile and juvenile/adult subtypes include psychomotor delay and deterioration, hepatosplenomegaly, dysostosis multiplex, cherry-red macular spots and corneal clouding, heart defects, and renal involvement. Neurological symptoms are common to the juvenile/adult form, but rare in the late infantile form. The early infantile form is associated with hydrops fetalis, visceromegaly, skeletal dysplasia, and early death.