GNPTG and mucolipidosis: 2011). In addition, the mutations in GNPTAB and GNPTG found in stuttering have been almost all missense mutations, unlike complete loss‐of‐function mutations frequently seen in mucolipidosis, and there is very little overlap in the location of mutations in these genes found in stuttering and those found in mucolipidosis (Raza et al. 2015a). The differences between mutations in these genes found in mucolipidosis and those found in stuttering are summarized in Table 3.