Some diseases not included in the table, such as in Fabry disease, present high prevalence of symptomatic heterozygous females, but it is due to the accumulation of neutral glycosphingolipids caused by a deficient alpha-galactosidase A; in fact, X-inactivation is random in heterozygous females of Fabry disease (Maier et al., 2006). Here, GLA is linked to Fabry disease.