Mucolipidosis type II, also known as I-cell disease, is an autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylglucosamine-1-phosphate transferase which is multimeric enzyme involved in phosphotransfer of UDP-N-acetylglucosamine to lysosomal enzymes (glycoproteins). It is the necessary process for the transport of newly synthesized lysosomal proteins to the lysosomes.
Mucolipidosis II (I-cell disease) and mucolipidosis IIIA (classical pseudo-hurler polydystrophy) are caused by mutations in the GlcNAc-phosphotransferase alpha / beta -subunits precursor gene.
