The majority of these severely affected MLII patients have nonsense, frameshift or splice site alterations in GNPTAB. In addition, there are patients carrying missense mutations in GNPTAB (MLIII alpha/beta; pseudo-Hurler polydystrophy) resulting in residual GlcNAc-1-phosphotransferase activity and a milder course of disease with a later onset of clinical signs and symptoms, permitting survival into adulthood (Bargal et al, 2006; Braulke et al, 2013; Cathey et al, 2008; Cathey et al, 2010). This evidence concerns the gene GNPTAB and mucolipidosis type III, alpha/beta.