I-cell disease is characterized by a deficiency in the enzyme ( ), which functions in protein tagging at the ( ).

N-acetylglucosaminyl-1-phosphotransferase
Golgi apparatus

I-cell disease presents with failure to thrive, coarse facial features, hepatomegaly, limited mobility, elevated plasma lysosomal enzymes, and vacuolization of cultured fibroblasts.

Rx Biochemistry