Eliglustat (Cerdelga®, Sanofi Genzyme, Cambridge, MA, USA) is an oral substrate reduction therapy (SRT) approved in more than 55 countries worldwide, including the United States [4] and the European Union [5], as a first-line treatment for adults with Gaucher disease type 1 who have a CYP2D6 extensive, intermediate, or poor metabolizer phenotype, which encompasses more than 90% of patients [6, 7]. Here, CYP2D6 is linked to Gaucher disease type 1.