Inclusion cell disease/mucolipidosis type II

Inherited lysosomal storage disorder; defect in N-acetylglucosaminyl-1-phosphotransferase → failure of the Golgi to phosphorylate mannose residues (ie, ↓ mannose-6-phosphate) on glycoproteins → proteins are secreted extracellularly rather than delivered to lysosomes.

Presentation: - Coarse facial features- Gingival hyperplasia- Clouded corneas- Restricted joint movement, kyphoscoliosis- Claw hand deformities- High levels of lysosomal enzymes

Often fatal in childhood.