In Gaucher disease (GD), biallelic mutations in GBA1 result in defective lysosomal glucocerebrosidase and the cellular accumulation of glucosylceramide (GlcCer) and its downstream metabolite, glucosylsphingosine (GlcSph) (Mistry et al., 2015; van Dussen et al., 2014). The gene discussed is GBA1; the disease is Gaucher disease.