GM1-gangliosidosis type II is an autosomal recessive lysosomal storage disease characterized by slowly progressive generalized neurodegeneration and mild skeletal changes, with onset between 7 months and 3 years of age. Unlike the severe infantile type I, type II is usually not associated with macular cherry-red spots or organomegaly. Within type II, those with somewhat earlier onset and earlier death are considered to have the 'late-infantile' form, whereas those with slightly later onset and survival into late childhood are referred to as having the 'juvenile' form
psychomotor regression and loss of developmental skills. By age 2 years, they had spastic quadriplegia with extensor plantar responses and tonic neck reflex. Optic discs were pale, but cherry-red spots were not observed. Visceromegaly, facial dysmorphism, and skeletal changes were not present.
A number sign (*) is used with this entry because GM1-gangliosidosis type II is caused by mutation in the gene encoding beta-galactosidase-1