“…Recently, we identified a novel gene, GNPTA, encoding a protein of 1,256 amino acids with two putative transmembrane domains and a complex module structure which is required for proper phosphotransferase activity [Tiede et al, 2005a]. Defects in GNPTA result in mucolipidosis type II (ML II, I-cell disease; MIM# 252500) [Paik et al, 2005;Tiede et al, 2005a;Kudo et al, 2006] whereas mutations in GNPTG were found in ML III patients (pseudo Hurler-polydystrophy; MIM# 252600) [Raas-Rothschild et al, 2000Tiede et al, 2004]. ML II patients are characterized by dwarfism, skeletal abnormalities, developmental delay and cardiomegaly leading to death between 5 and 8 years of age [Kornfeld and Sly, 2001;Spranger et al, 2002].…”